en/docs3-v2/java-sdk/reference-manual/protocol/triple/index.xml

<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>Apache Dubbo – Triple Protocol</title><link>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/</link><description>Recent content in Triple Protocol on Apache Dubbo</description><generator>Hugo -- gohugo.io</generator><language>en</language><atom:link href="https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/index.xml" rel="self" type="application/rss+xml"/><item><title>Docs3-V2: Protocol Overview</title><link>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/overview/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/overview/</guid><description>
&lt;h2 id="triple-overview">Triple overview&lt;/h2>
&lt;p>For the format and principle of the &lt;code>Triple&lt;/code> protocol, please refer to &lt;a href="https://dubbo.apache.org/zh-cn/docs/concepts/rpc-protocol/">RPC Communication Protocol&lt;/a>&lt;/p>
&lt;p>According to the goal of Triple design, the &lt;code>Triple&lt;/code> protocol has the following advantages&lt;/p>
&lt;ul>
&lt;li>Capable of cross-language interaction. Both the traditional multi-language and multi-SDK mode and the Mesh cross-language mode require a more general and scalable data transmission protocol.&lt;/li>
&lt;li>Provide a more complete request model. In addition to supporting the traditional Request/Response model (Unary one-way communication), it also supports Stream (streaming communication) and Bidirectional (two-way communication).&lt;/li>
&lt;li>Easy to expand, high penetration, including but not limited to Tracing / Monitoring and other support, should also be recognized by devices at all levels, gateway facilities, etc. can identify data packets, friendly to Service Mesh deployment, and reduce the difficulty of understanding for users.&lt;/li>
&lt;li>Fully compatible with grpc, the client/server can communicate with the native grpc client.&lt;/li>
&lt;li>Components in the existing grpc ecosystem can be reused to meet cross-language, cross-environment, and cross-platform intercommunication requirements in cloud-native scenarios.&lt;/li>
&lt;/ul>
&lt;p>For Dubbo users currently using other protocols, the framework provides migration capabilities compatible with existing serialization methods. Without affecting existing online businesses, the cost of migrating protocols is almost zero.&lt;/p>
&lt;h3 id="grpc-docking">grpc docking&lt;/h3>
&lt;p>Dubbo users who need to add grpc services can directly use the Triple protocol to get through, without the need to introduce grpc client separately to complete, not only can retain the existing ease of use of Dubbo, but also reduce the complexity of the program and development and maintenance Cost, it can be connected to the existing ecology without additional adaptation and development.&lt;/p>
&lt;h3 id="gateway-access">Gateway Access&lt;/h3>
&lt;p>For Dubbo users who need gateway access, the Triple protocol provides a more native way to make gateway development or use open source grpc gateway components easier. The gateway can choose not to parse the payload, which greatly improves the performance. When using the Dubbo protocol, the language-related serialization method is a big pain point for the gateway, and the traditional HTTP-to-Dubbo method is almost powerless for cross-language serialization. At the same time, since Triple&amp;rsquo;s protocol metadata is stored in the request header, the gateway can easily implement customized requirements, such as routing and current limiting.&lt;/p>
&lt;h2 id="common-problem">common problem&lt;/h2>
&lt;h3 id="protobuf-class-not-found">protobuf class not found&lt;/h3>
&lt;p>Since the bottom layer of the Triple protocol needs to rely on the protobuf protocol for transmission, even if the defined service interface does not use protobuf, it is necessary to introduce protobuf dependencies into the environment.&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-xml" data-lang="xml">&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>com.google.protobuf&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>protobuf-java&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>3.19.4&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div></description></item><item><title>Docs3-V2: Instructions for Use</title><link>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/guide/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/guide/</guid><description>
&lt;p>The Triple protocol is the main protocol of Dubbo3, fully compatible with gRPC over HTTP/2, and has expanded load balancing and flow control related mechanisms at the protocol level. This document is intended to guide users to use the Triple protocol correctly.&lt;/p>
&lt;p>Before starting, you need to decide the serialization method used by the service. If it is a new service, it is recommended to use protobuf as the default serialization, which will have better performance and cross-language effects. If the original service wants to upgrade the protocol, the Triple protocol already supports other serialization methods, such as Hessian / JSON, etc.&lt;/p>
&lt;h3 id="protobuf">Protobuf&lt;/h3>
&lt;ol>
&lt;li>
&lt;p>Write the IDL file&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-protobuf" data-lang="protobuf">&lt;span style="display:flex;">&lt;span>syntax &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">&amp;#34;proto3&amp;#34;&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">option&lt;/span> java_multiple_files &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#cb4b16">true&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">option&lt;/span> java_package &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.hello&amp;#34;&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">option&lt;/span> java_outer_classname &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">&amp;#34;HelloWorldProto&amp;#34;&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">option&lt;/span> objc_class_prefix &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">&amp;#34;HLW&amp;#34;&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">package&lt;/span> helloworld;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75">// The request message containing the user&amp;#39;s name.
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75">&lt;/span>&lt;span style="color:#268bd2">message&lt;/span> &lt;span style="color:#268bd2">HelloRequest&lt;/span> {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#dc322f">string&lt;/span> name &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">1&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>}
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75">// The response message containing the greetings
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75">&lt;/span>&lt;span style="color:#268bd2">message&lt;/span> &lt;span style="color:#268bd2">HelloReply&lt;/span> {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#dc322f">string&lt;/span> &lt;span style="color:#268bd2">message&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">1&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>}
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Add the extension and plugin for compiling protobuf (take maven as an example)&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-xml" data-lang="xml">&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;extensions&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;extension&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>kr.motd.maven&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>os-maven-plugin&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>1.6.1&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/extension&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/extensions&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;plugins&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;plugin&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>org.xolstice.maven.plugins&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>protobuf-maven-plugin&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>0.6.1&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;configuration&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;protocArtifact&amp;gt;&lt;/span>com.google.protobuf:protoc:3.7.1:exe:${os.detected.classifier}&lt;span style="color:#268bd2">&amp;lt;/protocArtifact&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;pluginId&amp;gt;&lt;/span>triple-java&lt;span style="color:#268bd2">&amp;lt;/pluginId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;outputDirectory&amp;gt;&lt;/span>build/generated/source/proto/main/java&lt;span style="color:#268bd2">&amp;lt;/outputDirectory&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/configuration&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;executions&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;execution&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;goals&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;goal&amp;gt;&lt;/span>compile&lt;span style="color:#268bd2">&amp;lt;/goal&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;goal&amp;gt;&lt;/span>test-compile&lt;span style="color:#268bd2">&amp;lt;/goal&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/goals&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/execution&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/executions&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/plugin&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/plugins&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Build/compile to generate protobuf Message class&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-shell" data-lang="shell">&lt;span style="display:flex;">&lt;span>$ mvn clean install
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;/ol>
&lt;h3 id="unary-way">Unary way&lt;/h3>
&lt;ol start="4">
&lt;li>
&lt;p>Writing the Java interface&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.hello.HelloReply&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.hello.HelloRequest&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">interface&lt;/span> &lt;span style="color:#268bd2">IGreeter&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#586e75">/**
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75"> * &amp;lt;pre&amp;gt;
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75"> * Sends a greeting
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75"> * &amp;lt;/pre&amp;gt;
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75"> */&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> HelloReply &lt;span style="color:#268bd2">sayHello&lt;/span>&lt;span style="color:#719e07">(&lt;/span>HelloRequest request&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Create a Provider&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">static&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">main&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String&lt;span style="color:#719e07">[]&lt;/span> args&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#268bd2">throws&lt;/span> InterruptedException &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ServiceConfig&lt;span style="color:#719e07">&amp;lt;&lt;/span>IGreeter&lt;span style="color:#719e07">&amp;gt;&lt;/span> service &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#719e07">new&lt;/span> ServiceConfig&lt;span style="color:#719e07">&amp;lt;&amp;gt;();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> service&lt;span style="color:#719e07">.&lt;/span>setInterface&lt;span style="color:#719e07">(&lt;/span>IGreeter&lt;span style="color:#719e07">.&lt;/span>class&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> service&lt;span style="color:#719e07">.&lt;/span>setRef&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> IGreeter1Impl&lt;span style="color:#719e07">());&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#586e75">// Here you need to show that the protocol used by the declaration is triple
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75">&lt;/span> service&lt;span style="color:#719e07">.&lt;/span>setProtocol&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> ProtocolConfig&lt;span style="color:#719e07">(&lt;/span>CommonConstants&lt;span style="color:#719e07">.&lt;/span>TRIPLE&lt;span style="color:#719e07">,&lt;/span> 50051&lt;span style="color:#719e07">));&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> service&lt;span style="color:#719e07">.&lt;/span>setApplication&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> ApplicationConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;demo-provider&amp;#34;&lt;/span>&lt;span style="color:#719e07">));&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> service&lt;span style="color:#719e07">.&lt;/span>setRegistry&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> RegistryConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;zookeeper://127.0.0.1:2181&amp;#34;&lt;/span>&lt;span style="color:#719e07">));&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> service&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">export&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;dubbo service started&amp;#34;&lt;/span>&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">new&lt;/span> CountDownLatch&lt;span style="color:#719e07">(&lt;/span>1&lt;span style="color:#719e07">).&lt;/span> await&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Create Consumer&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">static&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">main&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String&lt;span style="color:#719e07">[]&lt;/span> args&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#268bd2">throws&lt;/span> IOException &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ReferenceConfig&lt;span style="color:#719e07">&amp;lt;&lt;/span>IGreeter&lt;span style="color:#719e07">&amp;gt;&lt;/span> ref &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#719e07">new&lt;/span> ReferenceConfig&lt;span style="color:#719e07">&amp;lt;&amp;gt;();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">setInterface&lt;/span>&lt;span style="color:#719e07">(&lt;/span>IGreeter&lt;span style="color:#719e07">.&lt;/span> class&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">setCheck&lt;/span>&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#cb4b16">false&lt;/span>&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span>setProtocol&lt;span style="color:#719e07">(&lt;/span>CommonConstants&lt;span style="color:#719e07">.&lt;/span>TRIPLE&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">setLazy&lt;/span>&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#cb4b16">true&lt;/span>&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">setTimeout&lt;/span>&lt;span style="color:#719e07">(&lt;/span>100000&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">setApplication&lt;/span>&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> ApplicationConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;demo-consumer&amp;#34;&lt;/span>&lt;span style="color:#719e07">));&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span>setRegistry&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> RegistryConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;zookeeper://127.0.0.1:2181&amp;#34;&lt;/span>&lt;span style="color:#719e07">));&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">final&lt;/span> IGreeter iGreeter &lt;span style="color:#719e07">=&lt;/span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">get&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;dubbo ref started&amp;#34;&lt;/span>&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">try&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">final&lt;/span> HelloReply reply &lt;span style="color:#719e07">=&lt;/span> iGreeter&lt;span style="color:#719e07">.&lt;/span>sayHello&lt;span style="color:#719e07">(&lt;/span>HelloRequest&lt;span style="color:#719e07">.&lt;/span>newBuilder&lt;span style="color:#719e07">()&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>setName&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;name&amp;#34;&lt;/span>&lt;span style="color:#719e07">)&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>build&lt;span style="color:#719e07">());&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> TimeUnit&lt;span style="color:#719e07">.&lt;/span> SECONDS&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">sleep&lt;/span>&lt;span style="color:#719e07">(&lt;/span>1&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;Reply:&amp;#34;&lt;/span> &lt;span style="color:#719e07">+&lt;/span> reply&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span> &lt;span style="color:#719e07">catch&lt;/span> &lt;span style="color:#719e07">(&lt;/span>Throwable t&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> t&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">printStackTrace&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>in&lt;span style="color:#719e07">.&lt;/span>read&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Run Provider and Consumer, you can see that the request returns normally&lt;/p>
&lt;blockquote>
&lt;p>Reply: message: &amp;ldquo;name&amp;rdquo;&lt;/p>
&lt;/blockquote>
&lt;/li>
&lt;/ol>
&lt;h3 id="stream-mode">stream mode&lt;/h3>
&lt;ol start="8">
&lt;li>Writing Java Interfaces
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.hello.HelloReply&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.hello.HelloRequest&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">interface&lt;/span> &lt;span style="color:#268bd2">IGreeter&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#586e75">/**
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75"> * &amp;lt;pre&amp;gt;
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75"> * Sends greeting by stream
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75"> * &amp;lt;/pre&amp;gt;
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75">*/&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;/ol>
&lt;p>StreamObserver&lt;HelloRequest> sayHello(StreamObserver&lt;HelloReply> replyObserver);&lt;/p>
&lt;pre>&lt;code>}
```
&lt;/code>&lt;/pre>
&lt;ol start="9">
&lt;li>Write the implementation class
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;/ol>
&lt;p>public class IStreamGreeterImpl implements IStreamGreeter {&lt;/p>
&lt;p>@Override
public StreamObserver&lt;HelloRequest> sayHello(StreamObserver&lt;HelloReply> replyObserver) {&lt;/p>
&lt;p>return new StreamObserver&lt;HelloRequest>() {
private List&lt;HelloReply> replyList = new ArrayList&amp;lt;&amp;gt;();&lt;/p>
&lt;p>@Override
public void onNext(HelloRequest helloRequest) {
System.out.println(&amp;ldquo;onNext receive request name:&amp;rdquo; + helloRequest.getName());
replyList.add(HelloReply.newBuilder()
.setMessage(&amp;ldquo;receive name:&amp;rdquo; + helloRequest.getName())
.build());
}&lt;/p>
&lt;p>@Override
public void onError(Throwable cause) {
System.out.println(&amp;ldquo;onError&amp;rdquo;);
replyObserver.onError(cause);
}&lt;/p>
&lt;p>@Override
public void onCompleted() {
System.out.println(&amp;ldquo;onComplete receive request size:&amp;rdquo; + replyList.size());
for (HelloReply reply : replyList) {
replyObserver.onNext(reply);
}
replyObserver.onCompleted();
}
};
}
}&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>10. Create a Provider
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ```java
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>public class StreamProvider {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>public static void main(String[] args) throws InterruptedException {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>ServiceConfig&amp;lt;IStreamGreeter&amp;gt; service = new ServiceConfig&amp;lt;&amp;gt;();
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>service.setInterface(IStreamGreeter.class);
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>service.setRef(new IStreamGreeterImpl());
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>service.setProtocol(new ProtocolConfig(CommonConstants.TRIPLE, 50051));
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>service.setApplication(new ApplicationConfig(&amp;#34;stream-provider&amp;#34;));
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>service.setRegistry(new RegistryConfig(&amp;#34;zookeeper://127.0.0.1:2181&amp;#34;));
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>service. export();
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>System.out.println(&amp;#34;dubbo service started&amp;#34;);
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>new CountDownLatch(1). await();
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>}
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>}
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;ol start="11">
&lt;li>
&lt;p>Create Consumer&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;/ol>
&lt;p>public class StreamConsumer {
public static void main(String[] args) throws InterruptedException, IOException {
ReferenceConfig&lt;IStreamGreeter> ref = new ReferenceConfig&amp;lt;&amp;gt;();
ref. setInterface(IStreamGreeter. class);
ref. setCheck(false);
ref.setProtocol(CommonConstants.TRIPLE);
ref. setLazy(true);
ref. setTimeout(100000);
ref. setApplication(new ApplicationConfig(&amp;ldquo;stream-consumer&amp;rdquo;));
ref.setRegistry(new RegistryConfig(&amp;ldquo;zookeeper://mse-6e9fda00-p.zk.mse.aliyuncs.com:2181&amp;rdquo;));
final IStreamGreeter iStreamGreeter = ref. get();&lt;/p>
&lt;p>System.out.println(&amp;ldquo;dubbo ref started&amp;rdquo;);
try {&lt;/p>
&lt;p>StreamObserver&lt;HelloRequest> streamObserver = iStreamGreeter.sayHello(new StreamObserver&lt;HelloReply>() {
@Override
public void onNext(HelloReply reply) {
System.out.println(&amp;ldquo;onNext&amp;rdquo;);
System.out.println(reply.getMessage());
}&lt;/p>
&lt;p>@Override
public void onError(Throwable throwable) {
System.out.println(&amp;ldquo;onError:&amp;rdquo; + throwable.getMessage());
}&lt;/p>
&lt;p>@Override
public void onCompleted() {
System.out.println(&amp;ldquo;onCompleted&amp;rdquo;);
}
});&lt;/p>
&lt;p>streamObserver.onNext(HelloRequest.newBuilder()
.setName(&amp;ldquo;tony&amp;rdquo;)
.build());&lt;/p>
&lt;p>streamObserver.onNext(HelloRequest.newBuilder()
.setName(&amp;ldquo;nick&amp;rdquo;)
.build());&lt;/p>
&lt;p>streamObserver.onCompleted();
} catch (Throwable t) {
t. printStackTrace();
}
System.in.read();
}
}&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>12. Run Provider and Consumer, you can see that the request returns normally
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &amp;gt; onNext\
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &amp;gt; receive name:tony\
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &amp;gt; onNext\
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &amp;gt; receive name:nick\
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &amp;gt; onCompleted
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>### Other serialization methods
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>Omit steps 1-3 above, and specify the protocol used by Provider and Consumer to complete the protocol upgrade.
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>### Example program
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>The sample program of this article can be found in [triple-samples](https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple)
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div></description></item><item><title>Docs3-V2: POJO way to use Triple</title><link>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/pojo/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/pojo/</guid><description>
&lt;p>This tutorial will demonstrate how to use Dubbo Triple based on POJO by building a simple project from scratch, and upgrade to the Triple protocol while the application does not change the existing interface definition.&lt;/p>
&lt;h3 id="implementation-principle">Implementation principle&lt;/h3>
&lt;p>Through the upgrade process described above, we can easily complete the upgrade by modifying the protocol type. How does the framework help us do this?&lt;/p>
&lt;p>Through the introduction of the &lt;code>Triple&lt;/code> protocol, we know that the data type of &lt;code>Triple&lt;/code> in Dubbo3 is a &lt;code>protobuf&lt;/code> object, so why non-&lt;code>protobuf&lt;/code> java objects can also be transmitted normally.&lt;/p>
&lt;p>Here Dubbo3 uses an ingenious design, first judge whether the parameter type is a &lt;code>protobuf&lt;/code> object, if not. Use a &lt;code>protobuf&lt;/code> object to wrap &lt;code>request&lt;/code> and &lt;code>response&lt;/code>, which shields the complexity brought by other serialization. Declare the serialization type inside the &lt;code>wrapper&lt;/code> object to support serialization extensions.&lt;/p>
&lt;p>The IDL of &lt;code>protobuf&lt;/code> of wrapper is as follows:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-proto" data-lang="proto">&lt;span style="display:flex;">&lt;span>syntax &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">&amp;#34;proto3&amp;#34;&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">package&lt;/span> org&lt;span style="color:#719e07">.&lt;/span>apache.dubbo.triple;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">message&lt;/span> &lt;span style="color:#268bd2">TripleRequestWrapper&lt;/span> {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#586e75">//hessian4
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75">&lt;/span> &lt;span style="color:#586e75">// json
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75">&lt;/span> &lt;span style="color:#dc322f">string&lt;/span> serializeType &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">1&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">repeated&lt;/span> &lt;span style="color:#dc322f">bytes&lt;/span> args &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">2&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">repeated&lt;/span> &lt;span style="color:#dc322f">string&lt;/span> argTypes &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">3&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>}
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">message&lt;/span> &lt;span style="color:#268bd2">TripleResponseWrapper&lt;/span> {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#dc322f">string&lt;/span> serializeType &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">1&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#dc322f">bytes&lt;/span> data &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">2&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#dc322f">string&lt;/span> type &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">3&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>}
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>For requests, use &lt;code>TripleRequestWrapper&lt;/code> for wrapping, and for responses, use &lt;code>TripleResponseWrapper&lt;/code> for wrapping.&lt;/p>
&lt;blockquote>
&lt;p>For request parameters, you can see that args is modified by &lt;code>repeated&lt;/code>, this is because multiple parameters of the java method need to be supported. Of course, serialization can only be one. The implementation of serialization follows the spi implemented by Dubbo2&lt;/p>
&lt;/blockquote>
&lt;h3 id="precondition">precondition&lt;/h3>
&lt;ul>
&lt;li>&lt;a href="https://jdk.java.net/">JDK&lt;/a> version &amp;gt;= 8&lt;/li>
&lt;li>Installed &lt;a href="https://maven.apache.org/">Maven&lt;/a>&lt;/li>
&lt;li>Installed and started &lt;a href="https://zookeeper.apache.org/">Zookeeper&lt;/a>&lt;/li>
&lt;/ul>
&lt;h3 id="create-project">Create project&lt;/h3>
&lt;ol>
&lt;li>
&lt;p>First create an empty maven project&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span>$ mvn archetype:generate \
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -DgroupId=org.apache.dubbo\
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -DartifactId=tri-pojo-demo\
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -DarchetypeArtifactId=maven-archetype-quickstart \
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -DarchetypeVersion=1.4 \
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -DarchetypeGroupId=org.apache.maven.archetypes \
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -Dversion=1.0-SNAPSHOT
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Switch to the project directory&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span>$ cd tri-pojo-demo
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Set JDK version in &lt;code>pom.xml&lt;/code>, add Dubbo dependencies and plugins&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-xml" data-lang="xml">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;properties&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;project.build.sourceEncoding&amp;gt;&lt;/span>UTF-8&lt;span style="color:#268bd2">&amp;lt;/project.build.sourceEncoding&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;maven.compiler.source&amp;gt;&lt;/span>1.8&lt;span style="color:#268bd2">&amp;lt;/maven.compiler.source&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;maven.compiler.target&amp;gt;&lt;/span>1.8&lt;span style="color:#268bd2">&amp;lt;/maven.compiler.target&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;/properties&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;dependencies&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>junit&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>junit&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>4.13&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;scope&amp;gt;&lt;/span>test&lt;span style="color:#268bd2">&amp;lt;/scope&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>org.apache.dubbo&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>dubbo&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>3.0.8&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>org.apache.dubbo&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>dubbo-dependencies-zookeeper-curator5&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;type&amp;gt;&lt;/span>pom&lt;span style="color:#268bd2">&amp;lt;/type&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>3.0.8&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>com.google.protobuf&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>protobuf-java&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>3.19.4&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">&amp;lt;/dependencies&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Add interface definition &lt;code>src/main/java/org/apache/dubbo/Greeter.java&lt;/code>&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">package&lt;/span> org.apache.dubbo&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">interface&lt;/span> &lt;span style="color:#268bd2">Greeter&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> String &lt;span style="color:#268bd2">sayHello&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String name&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Add server-side interface implementation &lt;code>src/main/java/org/apache/dubbo/GreeterImpl.java&lt;/code>&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">package&lt;/span> org.apache.dubbo&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">class&lt;/span> &lt;span style="color:#268bd2">GreeterImpl&lt;/span> &lt;span style="color:#268bd2">implements&lt;/span> Greeter &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> String &lt;span style="color:#268bd2">sayHello&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String name&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">return&lt;/span> &lt;span style="color:#2aa198">&amp;#34;Hello,&amp;#34;&lt;/span> &lt;span style="color:#719e07">+&lt;/span> name &lt;span style="color:#719e07">+&lt;/span> &lt;span style="color:#2aa198">&amp;#34;!&amp;#34;&lt;/span>&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Add server startup class &lt;code>src/main/java/org/apache/dubbo/MyDubboServer.java&lt;/code>&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">package&lt;/span> org.apache.dubbo&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.common.constants.CommonConstants&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.ApplicationConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.ProtocolConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.RegistryConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.ServiceConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.bootstrap.DubboBootstrap&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> java.io.IOException&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">class&lt;/span> &lt;span style="color:#268bd2">MyDubboServer&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">static&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">main&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String&lt;span style="color:#719e07">[]&lt;/span> args&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#268bd2">throws&lt;/span> IOException &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ServiceConfig&lt;span style="color:#719e07">&amp;lt;&lt;/span>Greeter&lt;span style="color:#719e07">&amp;gt;&lt;/span> service &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#719e07">new&lt;/span> ServiceConfig&lt;span style="color:#719e07">&amp;lt;&amp;gt;();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> service&lt;span style="color:#719e07">.&lt;/span>setInterface&lt;span style="color:#719e07">(&lt;/span>Greeter&lt;span style="color:#719e07">.&lt;/span>class&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> service&lt;span style="color:#719e07">.&lt;/span>setRef&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> GreeterImpl&lt;span style="color:#719e07">());&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> DubboBootstrap bootstrap &lt;span style="color:#719e07">=&lt;/span> DubboBootstrap&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">getInstance&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> bootstrap&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">application&lt;/span>&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> ApplicationConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;tri-pojo-server&amp;#34;&lt;/span>&lt;span style="color:#719e07">))&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>registry&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> RegistryConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;zookeeper://127.0.0.1:2181&amp;#34;&lt;/span>&lt;span style="color:#719e07">))&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>protocol&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> ProtocolConfig&lt;span style="color:#719e07">(&lt;/span>CommonConstants&lt;span style="color:#719e07">.&lt;/span>TRIPLE&lt;span style="color:#719e07">,&lt;/span> 50051&lt;span style="color:#719e07">))&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>service&lt;span style="color:#719e07">(&lt;/span>service&lt;span style="color:#719e07">)&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>start&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;Dubbo triple pojo server started&amp;#34;&lt;/span>&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>in&lt;span style="color:#719e07">.&lt;/span>read&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Add the client startup class &lt;code>src/main/java/org/apache/dubbo/MyDubboClient.java&lt;/code>&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">package&lt;/span> org.apache.dubbo&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.common.constants.CommonConstants&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.ApplicationConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.ReferenceConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.RegistryConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.bootstrap.DubboBootstrap&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">class&lt;/span> &lt;span style="color:#268bd2">MyDubboClient&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">static&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">main&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String&lt;span style="color:#719e07">[]&lt;/span> args&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> DubboBootstrap bootstrap &lt;span style="color:#719e07">=&lt;/span> DubboBootstrap&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">getInstance&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ReferenceConfig&lt;span style="color:#719e07">&amp;lt;&lt;/span>Greeter&lt;span style="color:#719e07">&amp;gt;&lt;/span> ref &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#719e07">new&lt;/span> ReferenceConfig&lt;span style="color:#719e07">&amp;lt;&amp;gt;();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">setInterface&lt;/span>&lt;span style="color:#719e07">(&lt;/span>Greeter&lt;span style="color:#719e07">.&lt;/span> class&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span>setProtocol&lt;span style="color:#719e07">(&lt;/span>CommonConstants&lt;span style="color:#719e07">.&lt;/span>TRIPLE&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">setTimeout&lt;/span>&lt;span style="color:#719e07">(&lt;/span>3000&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> bootstrap&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">application&lt;/span>&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> ApplicationConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;tri-pojo-client&amp;#34;&lt;/span>&lt;span style="color:#719e07">))&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>registry&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> RegistryConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;zookeeper://127.0.0.1:2181&amp;#34;&lt;/span>&lt;span style="color:#719e07">))&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>reference&lt;span style="color:#719e07">(&lt;/span>ref&lt;span style="color:#719e07">)&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>start&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> Greeter greeter &lt;span style="color:#719e07">=&lt;/span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">get&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> String reply &lt;span style="color:#719e07">=&lt;/span> greeter&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">sayHello&lt;/span>&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;pojo&amp;#34;&lt;/span>&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;Received reply:&amp;#34;&lt;/span> &lt;span style="color:#719e07">+&lt;/span> reply&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Compile the code&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span>$ mvn clean install
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Start the server&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span>$ mvn org.codehaus.mojo:exec-maven-plugin:3.0.0:java -Dexec.mainClass=&amp;#34;org.apache.dubbo.MyDubboServer&amp;#34;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>Dubbo triple pojo server started
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;/li>
&lt;li>
&lt;p>Open a new terminal and start the client&lt;/p>
&lt;/li>
&lt;/ol>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span>$ mvn org.codehaus.mojo:exec-maven-plugin:3.0.0:java -Dexec.mainClass=&amp;#34;org.apache.dubbo.MyDubboClient&amp;#34;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>Received reply: message: &amp;#34;Hello, Demo!&amp;#34;
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div></description></item><item><title>Docs3-V2: Using Triple in IDL</title><link>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/idl/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/idl/</guid><description>
&lt;p>This tutorial will demonstrate how to use Dubbo Triple based on IDL by building a simple project from scratch&lt;/p>
&lt;h2 id="precondition">precondition&lt;/h2>
&lt;ul>
&lt;li>&lt;a href="https://jdk.java.net/">JDK&lt;/a> version &amp;gt;= 8&lt;/li>
&lt;li>Installed &lt;a href="https://maven.apache.org/">Maven&lt;/a>&lt;/li>
&lt;li>Installed and started &lt;a href="https://zookeeper.apache.org/">Zookeeper&lt;/a>&lt;/li>
&lt;/ul>
&lt;h2 id="create-project">Create project&lt;/h2>
&lt;h3 id="1-create-an-empty-maven-project">1. Create an empty maven project&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span>$ mvn archetype:generate \
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -DgroupId=org.apache.dubbo\
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -DartifactId=tri-stub-demo \
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -DarchetypeArtifactId=maven-archetype-quickstart \
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -DarchetypeVersion=1.4 \
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -DarchetypeGroupId=org.apache.maven.archetypes \
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> -Dversion=1.0-SNAPSHOT
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="2-switch-to-the-project-directory">2. Switch to the project directory&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span> $ cd tri-stub-demo
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="3-add-dubbo-dependencies-and-plugins">3. Add Dubbo dependencies and plugins&lt;/h3>
&lt;p>Set JDK version in &lt;code>pom.xml&lt;/code>&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-xml" data-lang="xml">&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;properties&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;project.build.sourceEncoding&amp;gt;&lt;/span>UTF-8&lt;span style="color:#268bd2">&amp;lt;/project.build.sourceEncoding&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;maven.compiler.source&amp;gt;&lt;/span>1.8&lt;span style="color:#268bd2">&amp;lt;/maven.compiler.source&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;maven.compiler.target&amp;gt;&lt;/span>1.8&lt;span style="color:#268bd2">&amp;lt;/maven.compiler.target&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dubbo.version&amp;gt;&lt;/span>3.1.7&lt;span style="color:#268bd2">&amp;lt;/dubbo.version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/properties&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dependencies&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>junit&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>junit&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>4.13&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;scope&amp;gt;&lt;/span>test&lt;span style="color:#268bd2">&amp;lt;/scope&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>org.apache.dubbo&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>dubbo&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>${dubbo.version}&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>org.apache.dubbo&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>dubbo-dependencies-zookeeper-curator5&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;type&amp;gt;&lt;/span>pom&lt;span style="color:#268bd2">&amp;lt;/type&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>${dubbo.version}&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>com.google.protobuf&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>protobuf-java&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>3.19.4&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/dependency&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/dependencies&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;build&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;extensions&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;extension&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>kr.motd.maven&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>os-maven-plugin&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>1.6.1&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/extension&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/extensions&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;plugins&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;plugin&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>org.xolstice.maven.plugins&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>protobuf-maven-plugin&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>0.6.1&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;configuration&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;protocArtifact&amp;gt;&lt;/span>com.google.protobuf:protoc:3.19.4:exe:${os.detected.classifier}&lt;span style="color:#268bd2">&amp;lt;/protocArtifact&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;protocPlugins&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;protocPlugin&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;id&amp;gt;&lt;/span>dubbo&lt;span style="color:#268bd2">&amp;lt;/id&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;groupId&amp;gt;&lt;/span>org.apache.dubbo&lt;span style="color:#268bd2">&amp;lt;/groupId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;artifactId&amp;gt;&lt;/span>dubbo-compiler&lt;span style="color:#268bd2">&amp;lt;/artifactId&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;version&amp;gt;&lt;/span>${dubbo.version}&lt;span style="color:#268bd2">&amp;lt;/version&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;mainClass&amp;gt;&lt;/span>org.apache.dubbo.gen.tri.Dubbo3TripleGenerator&lt;span style="color:#268bd2">&amp;lt;/mainClass&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/protocPlugin&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/protocPlugins&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/configuration&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;executions&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;execution&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;goals&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;goal&amp;gt;&lt;/span>compile&lt;span style="color:#268bd2">&amp;lt;/goal&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/goals&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/execution&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/executions&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/plugin&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/plugins&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">&amp;lt;/build&amp;gt;&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="4-add-interface-definition-file">4. Add interface definition file&lt;/h3>
&lt;p>&lt;code>src/main/proto/hello.proto&lt;/code>, Dubbo uses &lt;a href="https://developers.google.com/protocol-buffers">Protobuf&lt;/a> as IDL&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-protobuf" data-lang="protobuf">&lt;span style="display:flex;">&lt;span> syntax &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">&amp;#34;proto3&amp;#34;&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">option&lt;/span> java_multiple_files &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#cb4b16">true&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">option&lt;/span> java_package &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.hello&amp;#34;&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">option&lt;/span> java_outer_classname &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">&amp;#34;HelloWorldProto&amp;#34;&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">option&lt;/span> objc_class_prefix &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">&amp;#34;HLW&amp;#34;&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">package&lt;/span> helloworld;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">message&lt;/span> &lt;span style="color:#268bd2">HelloRequest&lt;/span> {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#dc322f">string&lt;/span> name &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">1&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">message&lt;/span> &lt;span style="color:#268bd2">HelloReply&lt;/span> {
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#dc322f">string&lt;/span> &lt;span style="color:#268bd2">message&lt;/span> &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">1&lt;/span>;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">service&lt;/span> Greeter{
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">rpc&lt;/span> greet(HelloRequest) &lt;span style="color:#719e07">returns&lt;/span> (HelloReply);
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> }
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="5-compile-idl">5. Compile IDL&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span> $ mvn clean install
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;p>After the compilation is successful, you can see that the code file is generated in the &lt;code>target/generated-sources/protobuf/java&lt;/code> directory&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span> $ ls org/apache/dubbo/hello/
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> DubboGreeterTriple.java HelloReply.java HelloRequest.java HelloWorldProto.java
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> Greeter.java HelloReplyOrBuilder.java HelloRequestOrBuilder.java
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="6-add-server-interface-implementation">6. Add server interface implementation&lt;/h3>
&lt;p>&lt;code>src/main/java/org/apache/dubbo/GreeterImpl.java&lt;/code>&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">package&lt;/span> org.apache.dubbo&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.hello.DubboGreeterTriple&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.hello.HelloReply&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.hello.HelloRequest&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">class&lt;/span> &lt;span style="color:#268bd2">GreeterImpl&lt;/span> &lt;span style="color:#268bd2">extends&lt;/span> DubboGreeterTriple&lt;span style="color:#719e07">.&lt;/span> GreeterImplBase &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> HelloReply &lt;span style="color:#268bd2">greet&lt;/span>&lt;span style="color:#719e07">(&lt;/span>HelloRequest request&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">return&lt;/span> HelloReply&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">newBuilder&lt;/span>&lt;span style="color:#719e07">()&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>setMessage&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;Hello,&amp;#34;&lt;/span> &lt;span style="color:#719e07">+&lt;/span> request&lt;span style="color:#719e07">.&lt;/span>getName&lt;span style="color:#719e07">()&lt;/span> &lt;span style="color:#719e07">+&lt;/span> &lt;span style="color:#2aa198">&amp;#34;!&amp;#34;&lt;/span>&lt;span style="color:#719e07">)&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>build&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="7-add-server-startup-class">7. Add server startup class&lt;/h3>
&lt;p>&lt;code>src/main/java/org/apache/dubbo/MyDubboServer.java&lt;/code>&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">package&lt;/span> org.apache.dubbo&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.common.constants.CommonConstants&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.ApplicationConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.ProtocolConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.RegistryConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.ServiceConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.bootstrap.DubboBootstrap&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.hello.Greeter&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> java.io.IOException&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">class&lt;/span> &lt;span style="color:#268bd2">MyDubboServer&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">static&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">main&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String&lt;span style="color:#719e07">[]&lt;/span> args&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#268bd2">throws&lt;/span> IOException &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ServiceConfig&lt;span style="color:#719e07">&amp;lt;&lt;/span>Greeter&lt;span style="color:#719e07">&amp;gt;&lt;/span> service &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#719e07">new&lt;/span> ServiceConfig&lt;span style="color:#719e07">&amp;lt;&amp;gt;();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> service&lt;span style="color:#719e07">.&lt;/span>setInterface&lt;span style="color:#719e07">(&lt;/span>Greeter&lt;span style="color:#719e07">.&lt;/span>class&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> service&lt;span style="color:#719e07">.&lt;/span>setRef&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> GreeterImpl&lt;span style="color:#719e07">());&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> DubboBootstrap bootstrap &lt;span style="color:#719e07">=&lt;/span> DubboBootstrap&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">getInstance&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> bootstrap&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">application&lt;/span>&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> ApplicationConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;tri-stub-server&amp;#34;&lt;/span>&lt;span style="color:#719e07">))&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>registry&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> RegistryConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;zookeeper://127.0.0.1:2181&amp;#34;&lt;/span>&lt;span style="color:#719e07">))&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>protocol&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> ProtocolConfig&lt;span style="color:#719e07">(&lt;/span>CommonConstants&lt;span style="color:#719e07">.&lt;/span>TRIPLE&lt;span style="color:#719e07">,&lt;/span> 50051&lt;span style="color:#719e07">))&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>service&lt;span style="color:#719e07">(&lt;/span>service&lt;span style="color:#719e07">)&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>start&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;Dubbo triple stub server started&amp;#34;&lt;/span>&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>in&lt;span style="color:#719e07">.&lt;/span>read&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="8-add-client-startup-class">8. Add client startup class&lt;/h3>
&lt;p>&lt;code>src/main/java/org/apache/dubbo/MyDubboClient.java&lt;/code>&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">package&lt;/span> org.apache.dubbo&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.common.constants.CommonConstants&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.ApplicationConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.ReferenceConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.RegistryConfig&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.config.bootstrap.DubboBootstrap&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.hello.Greeter&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.hello.HelloReply&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">import&lt;/span> org.apache.dubbo.hello.HelloRequest&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">class&lt;/span> &lt;span style="color:#268bd2">MyDubboClient&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">static&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">main&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String&lt;span style="color:#719e07">[]&lt;/span> args&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> DubboBootstrap bootstrap &lt;span style="color:#719e07">=&lt;/span> DubboBootstrap&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">getInstance&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ReferenceConfig&lt;span style="color:#719e07">&amp;lt;&lt;/span>Greeter&lt;span style="color:#719e07">&amp;gt;&lt;/span> ref &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#719e07">new&lt;/span> ReferenceConfig&lt;span style="color:#719e07">&amp;lt;&amp;gt;();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">setInterface&lt;/span>&lt;span style="color:#719e07">(&lt;/span>Greeter&lt;span style="color:#719e07">.&lt;/span> class&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span>setProtocol&lt;span style="color:#719e07">(&lt;/span>CommonConstants&lt;span style="color:#719e07">.&lt;/span>TRIPLE&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span>setProxy&lt;span style="color:#719e07">(&lt;/span>CommonConstants&lt;span style="color:#719e07">.&lt;/span>NATIVE_STUB&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">setTimeout&lt;/span>&lt;span style="color:#719e07">(&lt;/span>3000&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> bootstrap&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">application&lt;/span>&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> ApplicationConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;tri-stub-client&amp;#34;&lt;/span>&lt;span style="color:#719e07">))&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>registry&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> RegistryConfig&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;zookeeper://127.0.0.1:2181&amp;#34;&lt;/span>&lt;span style="color:#719e07">))&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>reference&lt;span style="color:#719e07">(&lt;/span>ref&lt;span style="color:#719e07">)&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">.&lt;/span>start&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> Greeter greeter &lt;span style="color:#719e07">=&lt;/span> ref&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">get&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> HelloRequest request &lt;span style="color:#719e07">=&lt;/span> HelloRequest&lt;span style="color:#719e07">.&lt;/span>newBuilder&lt;span style="color:#719e07">().&lt;/span>setName&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;Demo&amp;#34;&lt;/span>&lt;span style="color:#719e07">).&lt;/span>build&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> HelloReply reply &lt;span style="color:#719e07">=&lt;/span> greeter&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">greet&lt;/span>&lt;span style="color:#719e07">(&lt;/span>request&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;Received reply:&amp;#34;&lt;/span> &lt;span style="color:#719e07">+&lt;/span> reply&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="9-compile-the-code">9. Compile the code&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span>$ mvn clean install
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="10-start-the-server">10. Start the server&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span>$ mvn org.codehaus.mojo:exec-maven-plugin:3.0.0:java -Dexec.mainClass=&amp;#34;org.apache.dubbo.MyDubboServer&amp;#34;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>Dubbo triple stub server started
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="11-open-a-new-terminal-and-start-the-client">11. Open a new terminal and start the client&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-fallback" data-lang="fallback">&lt;span style="display:flex;">&lt;span>$ mvn org.codehaus.mojo:exec-maven-plugin:3.0.0:java -Dexec.mainClass=&amp;#34;org.apache.dubbo.MyDubboClient&amp;#34;
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>Received reply: message: &amp;#34;Hello, Demo!&amp;#34;
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div></description></item><item><title>Docs3-V2: Dubbo2 Protocol Migration</title><link>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/migration/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/migration/</guid><description>
&lt;h2 id="dubbo2-protocol-migration-process">Dubbo2 protocol migration process&lt;/h2>
&lt;p>Dubbo2 users use dubbo protocol + custom serialization, such as hessian2 to complete remote calls.&lt;/p>
&lt;p>By default, Grpc only supports Protobuf serialization, and it cannot support multi-parameter and method overloading in the Java language.&lt;/p>
&lt;p>At the beginning of Dubbo3, one goal was to be perfectly compatible with Dubbo2. Therefore, in order to ensure the smooth upgrade of Dubbo2, the Dubbo framework has done a lot of work to ensure that the upgrade is seamless. Currently, the default serialization is consistent with Dubbo2 as &lt;code>hessian2&lt;/code>.&lt;/p>
&lt;p>Therefore, if you decide to upgrade to the &lt;code>Triple&lt;/code> protocol of Dubbo3, you only need to modify the protocol name in the configuration to &lt;code>tri&lt;/code> (note: not triple).&lt;/p>
&lt;p>Next we use a [project] (&lt;a href="https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple/src/main/java/">https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple/src/main/java/&lt;/a> org/apache/dubbo/sample/tri/migration) as an example, how to upgrade safely step by step.&lt;/p>
&lt;ol>
&lt;li>Only use the &lt;code>dubbo&lt;/code> protocol to start &lt;code>provider&lt;/code> and &lt;code>consumer&lt;/code>, and complete the call.&lt;/li>
&lt;li>Use &lt;code>dubbo&lt;/code> and &lt;code>tri&lt;/code> protocols to start &lt;code>provider&lt;/code>, use &lt;code>dubbo&lt;/code> protocol to start &lt;code>consumer&lt;/code>, and complete the call.&lt;/li>
&lt;li>Start &lt;code>provider&lt;/code> and &lt;code>consumer&lt;/code> using only &lt;code>tri&lt;/code> protocol, and complete the call.&lt;/li>
&lt;/ol>
&lt;h3 id="define-the-service">Define the service&lt;/h3>
&lt;ol>
&lt;li>Define the interface&lt;/li>
&lt;/ol>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">interface&lt;/span> &lt;span style="color:#268bd2">IWrapperGreeter&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#586e75">//...
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75">&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#586e75">/**
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75"> * This is a normal interface, not serialized using pb
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75"> */&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> String &lt;span style="color:#268bd2">sayHello&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String request&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;ol start="2">
&lt;li>The implementation class is as follows&lt;/li>
&lt;/ol>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">class&lt;/span> &lt;span style="color:#268bd2">IGreeter2Impl&lt;/span> &lt;span style="color:#268bd2">implements&lt;/span> IWrapperGreeter &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> String &lt;span style="color:#268bd2">sayHello&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String request&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">return&lt;/span> &lt;span style="color:#2aa198">&amp;#34;hello,&amp;#34;&lt;/span> &lt;span style="color:#719e07">+&lt;/span> request&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="only-use-dubbo-protocol">Only use dubbo protocol&lt;/h3>
&lt;p>To ensure compatibility, we first upgrade some providers to the &lt;code>dubbo3&lt;/code> version and use the &lt;code>dubbo&lt;/code> protocol.&lt;/p>
&lt;p>Start a [&lt;code>Provider&lt;/code>] using the &lt;code>dubbo&lt;/code> protocol (&lt;a href="https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple/src/main/java/org">https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple/src/main/java/org&lt;/a> /apache/dubbo/sample/tri/migration/ApiMigrationDubboProvider.java) and &lt;a href="https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple/src/main/java/org/apache/dubbo/sample/tri/migration/ApiMigrationDubboConsumer.java">&lt;code>Consumer&lt;/code>&lt;/a>, complete the call, the output is as follows:
&lt;img src="https://dubbo.apache.org/imgs/v3/migration/tri/dubbo3-tri-migration-dubbo-dubbo-result.png" alt="result">&lt;/p>
&lt;h3 id="use-dubbo-and-triple-protocol-at-the-same-time">Use dubbo and triple protocol at the same time&lt;/h3>
&lt;p>For the upgrade of online services, it is impossible to complete the provider and consumer upgrades at the same time. It needs to be operated step by step to ensure business stability.
In the second step, the provider provides a dual-protocol way to support dubbo + tri clients at the same time.&lt;/p>
&lt;p>The structure is shown in the figure:
&lt;img src="https://dubbo.apache.org/imgs/v3/migration/tri/migrate-dubbo-tri-strust.png" alt="trust">&lt;/p>
&lt;blockquote>
&lt;p>According to the recommended upgrade steps, the provider already supports the tri protocol, so the consumer of dubbo3 can directly use the tri protocol&lt;/p>
&lt;/blockquote>
&lt;p>Start [&lt;code>Provider&lt;/code>] using &lt;code>dubbo&lt;/code> protocol and &lt;code>triple&lt;/code> protocol (&lt;a href="https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple/src/main">https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple/src/main&lt;/a> /java/org/apache/dubbo/sample/tri/migration/ApiMigrationBothProvider.java) and [&lt;code>Consumer&lt;/code>](&lt;a href="https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/">https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/&lt;/a> dubbo-samples-triple/src/main/java/org/apache/dubbo/sample/tri/migration/ApiMigrationBothConsumer.java), complete the call, the output is as follows:&lt;/p>
&lt;p>&lt;img src="https://dubbo.apache.org/imgs/v3/migration/tri/dubbo3-tri-migration-both-dubbo-tri-result.png" alt="result">&lt;/p>
&lt;h3 id="only-use-triple-protocol">Only use triple protocol&lt;/h3>
&lt;p>When all consuemr are upgraded to a version that supports the &lt;code>Triple&lt;/code> protocol, the provider can be switched to only use the &lt;code>Triple&lt;/code> protocol to start&lt;/p>
&lt;p>The structure is shown in the figure:
&lt;img src="https://dubbo.apache.org/imgs/v3/migration/tri/migrate-only-tri-strust.png" alt="trust">&lt;/p>
&lt;p>[Provider](&lt;a href="https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple/src/main/java/org/apache/dubbo/sample/tri/">https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple/src/main/java/org/apache/dubbo/sample/tri/&lt;/a> migration/ApiMigrationTriProvider.java)
and [Consumer](&lt;a href="https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple/src/main/java/org/apache/dubbo/sample/tri">https://github.com/apache/dubbo-samples/tree/master/3-extensions/protocol/dubbo-samples-triple/src/main/java/org/apache/dubbo/sample/tri&lt;/a> /migration/ApiMigrationTriConsumer.java) to complete the call, the output is as follows:&lt;/p>
&lt;p>&lt;img src="https://dubbo.apache.org/imgs/v3/migration/tri/dubbo3-tri-migration-tri-tri-result.png" alt="result">&lt;/p></description></item><item><title>Docs3-V2: Streaming Communication</title><link>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/streaming/</link><pubDate>Mon, 01 Jan 0001 00:00:00 +0000</pubDate><guid>https://dubbo.apache.org/en/docs3-v2/java-sdk/reference-manual/protocol/triple/streaming/</guid><description>
&lt;h2 id="implementation-principle-of-stream">Implementation principle of stream&lt;/h2>
&lt;p>Stream mode for the &lt;code>Triple&lt;/code> protocol&lt;/p>
&lt;ul>
&lt;li>
&lt;p>From the perspective of the protocol layer, &lt;code>Triple&lt;/code> is built on the basis of &lt;code>HTTP2&lt;/code>, so it directly has all the capabilities of &lt;code>HTTP2&lt;/code>, so it has the ability to split &lt;code>stream&lt;/code> and full-duplex.&lt;/p>
&lt;/li>
&lt;li>
&lt;p>In terms of the framework layer, &lt;code>StreamObserver&lt;/code> is provided to users as a stream interface to provide stream processing for input and output parameters. The framework makes corresponding interface calls when sending and receiving stream data, so as to ensure the integrity of the life cycle of the stream.&lt;/p>
&lt;/li>
&lt;/ul>
&lt;h2 id="enable-new-features-of-triple">Enable new features of Triple&lt;/h2>
&lt;h3 id="stream-stream">Stream stream&lt;/h3>
&lt;p>Stream is a new call type provided by Dubbo3. It is recommended to use stream in the following scenarios:&lt;/p>
&lt;ul>
&lt;li>The interface needs to send a large amount of data. These data cannot be placed in an RPC request or response, and need to be sent in batches. However, if the application layer cannot solve the order and performance problems in the traditional multiple RPC method, if the order needs to be guaranteed , it can only be sent serially&lt;/li>
&lt;li>In streaming scenarios, data needs to be processed in the order they are sent, and the data itself has no definite boundary&lt;/li>
&lt;li>In push scenarios, multiple messages are sent and processed in the context of the same call&lt;/li>
&lt;/ul>
&lt;p>Stream is divided into the following three types:&lt;/p>
&lt;ul>
&lt;li>SERVER_STREAM (server stream)
&lt;img src="https://dubbo.apache.org/imgs/v3/migration/tri/migrate-server-stream.png" alt="SERVER_STREAM">&lt;/li>
&lt;li>CLIENT_STREAM (client stream)
&lt;img src="https://dubbo.apache.org/imgs/v3/migration/tri/migrate-client-stream.png" alt="CLIENT_STREAM">&lt;/li>
&lt;li>BIDIRECTIONAL_STREAM (bidirectional stream)
&lt;img src="https://dubbo.apache.org/imgs/v3/migration/tri/migrate-bi-stream.png" alt="BIDIRECTIONAL_STREAM">&lt;/li>
&lt;/ul>
&lt;blockquote>
&lt;p>Due to the limitations of the &lt;code>java&lt;/code> language, the implementation of BIDIRECTIONAL_STREAM and CLIENT_STREAM is the same.&lt;/p>
&lt;/blockquote>
&lt;p>In Dubbo3, the stream interface is declared and used as &lt;code>SteamObserver&lt;/code>, and users can use and implement this interface to send and handle stream data, exceptions, and end.&lt;/p>
&lt;blockquote>
&lt;p>For Dubbo2 users, they may be unfamiliar with StreamObserver, which is a stream type defined by Dubbo3. There is no Stream type in Dubbo2, so it has no impact on migration scenarios.&lt;/p>
&lt;/blockquote>
&lt;p>Stream Semantic Guarantees&lt;/p>
&lt;ul>
&lt;li>Provide message boundaries, which can easily process messages separately&lt;/li>
&lt;li>Strictly ordered, the order of the sender is consistent with the order of the receiver&lt;/li>
&lt;li>Full duplex, no need to wait for sending&lt;/li>
&lt;li>Support cancellation and timeout&lt;/li>
&lt;/ul>
&lt;h2 id="non-pb-serialized-stream">Non-PB serialized stream&lt;/h2>
&lt;h3 id="apis">APIs&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">interface&lt;/span> &lt;span style="color:#268bd2">IWrapperGreeter&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>String&lt;span style="color:#719e07">&amp;gt;&lt;/span> &lt;span style="color:#268bd2">sayHelloStream&lt;/span>&lt;span style="color:#719e07">(&lt;/span>StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>String&lt;span style="color:#719e07">&amp;gt;&lt;/span> response&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">sayHelloServerStream&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String request&lt;span style="color:#719e07">,&lt;/span> StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>String&lt;span style="color:#719e07">&amp;gt;&lt;/span> response&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;blockquote>
&lt;p>The method input parameters and return values of the Stream method are strictly agreed. In order to prevent problems caused by writing errors, the Dubbo3 framework side checks the parameters, and throws an exception if there is an error.
For &lt;code>BIDIRECTIONAL_STREAM&lt;/code>, it should be noted that &lt;code>StreamObserver&lt;/code> in the parameter is the response stream, and &lt;code>StreamObserver&lt;/code> in the return parameter is the request stream.&lt;/p>
&lt;/blockquote>
&lt;h3 id="implementation-class">Implementation class&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">class&lt;/span> &lt;span style="color:#268bd2">WrapGreeterImpl&lt;/span> &lt;span style="color:#268bd2">implements&lt;/span> WrapGreeter &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#586e75">//...
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75">&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>String&lt;span style="color:#719e07">&amp;gt;&lt;/span> &lt;span style="color:#268bd2">sayHelloStream&lt;/span>&lt;span style="color:#719e07">(&lt;/span>StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>String&lt;span style="color:#719e07">&amp;gt;&lt;/span> response&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">return&lt;/span> &lt;span style="color:#719e07">new&lt;/span> StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>String&lt;span style="color:#719e07">&amp;gt;()&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">onNext&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String data&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>data&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> response&lt;span style="color:#719e07">.&lt;/span>onNext&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;hello,&amp;#34;&lt;/span>&lt;span style="color:#719e07">+&lt;/span>data&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">onError&lt;/span>&lt;span style="color:#719e07">(&lt;/span>Throwable throwable&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> throwable&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">printStackTrace&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">onCompleted&lt;/span>&lt;span style="color:#719e07">()&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;onCompleted&amp;#34;&lt;/span>&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> response&lt;span style="color:#719e07">.&lt;/span>onCompleted&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">};&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">sayHelloServerStream&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String request&lt;span style="color:#719e07">,&lt;/span> StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>String&lt;span style="color:#719e07">&amp;gt;&lt;/span> response&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">for&lt;/span> &lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#dc322f">int&lt;/span> i &lt;span style="color:#719e07">=&lt;/span> 0&lt;span style="color:#719e07">;&lt;/span> i &lt;span style="color:#719e07">&amp;lt;&lt;/span> 10&lt;span style="color:#719e07">;&lt;/span> i&lt;span style="color:#719e07">++)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> response&lt;span style="color:#719e07">.&lt;/span>onNext&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;hello,&amp;#34;&lt;/span> &lt;span style="color:#719e07">+&lt;/span> request&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> response&lt;span style="color:#719e07">.&lt;/span>onCompleted&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h3 id="call-method">Call method&lt;/h3>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>delegate&lt;span style="color:#719e07">.&lt;/span>sayHelloServerStream&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;server stream&amp;#34;&lt;/span>&lt;span style="color:#719e07">,&lt;/span> &lt;span style="color:#719e07">new&lt;/span> StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>String&lt;span style="color:#719e07">&amp;gt;()&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">onNext&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String data&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>data&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">onError&lt;/span>&lt;span style="color:#719e07">(&lt;/span>Throwable throwable&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> throwable&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">printStackTrace&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">onCompleted&lt;/span>&lt;span style="color:#719e07">()&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;onCompleted&amp;#34;&lt;/span>&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">});&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>String&lt;span style="color:#719e07">&amp;gt;&lt;/span> request &lt;span style="color:#719e07">=&lt;/span> delegate&lt;span style="color:#719e07">.&lt;/span>sayHelloStream&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#719e07">new&lt;/span> StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>String&lt;span style="color:#719e07">&amp;gt;()&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">onNext&lt;/span>&lt;span style="color:#719e07">(&lt;/span>String data&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>data&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">onError&lt;/span>&lt;span style="color:#719e07">(&lt;/span>Throwable throwable&lt;span style="color:#719e07">)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> throwable&lt;span style="color:#719e07">.&lt;/span> &lt;span style="color:#268bd2">printStackTrace&lt;/span>&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">@Override&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">onCompleted&lt;/span>&lt;span style="color:#719e07">()&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> System&lt;span style="color:#719e07">.&lt;/span>out&lt;span style="color:#719e07">.&lt;/span>println&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;onCompleted&amp;#34;&lt;/span>&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">});&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">for&lt;/span> &lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#dc322f">int&lt;/span> i &lt;span style="color:#719e07">=&lt;/span> 0&lt;span style="color:#719e07">;&lt;/span> i &lt;span style="color:#719e07">&amp;lt;&lt;/span> n&lt;span style="color:#719e07">;&lt;/span> i&lt;span style="color:#719e07">++)&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> request&lt;span style="color:#719e07">.&lt;/span>onNext&lt;span style="color:#719e07">(&lt;/span>&lt;span style="color:#2aa198">&amp;#34;stream request&amp;#34;&lt;/span> &lt;span style="color:#719e07">+&lt;/span> i&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>request&lt;span style="color:#719e07">.&lt;/span>onCompleted&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div>&lt;h2 id="serialized-stream-using-protobuf">Serialized stream using Protobuf&lt;/h2>
&lt;p>For the &lt;code>Protobuf&lt;/code> serialization method, it is recommended to write &lt;code>IDL&lt;/code> and use the &lt;code>compiler&lt;/code> plugin to compile and generate. The generated code is roughly as follows:&lt;/p>
&lt;div class="highlight">&lt;pre tabindex="0" style="color:#93a1a1;background-color:#002b36;-moz-tab-size:4;-o-tab-size:4;tab-size:4;">&lt;code class="language-java" data-lang="java">&lt;span style="display:flex;">&lt;span>&lt;span style="color:#268bd2">public&lt;/span> &lt;span style="color:#268bd2">interface&lt;/span> &lt;span style="color:#268bd2">PbGreeter&lt;/span> &lt;span style="color:#719e07">{&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">static&lt;/span> &lt;span style="color:#268bd2">final&lt;/span> String JAVA_SERVICE_NAME &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.sample.tri.PbGreeter&amp;#34;&lt;/span>&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">static&lt;/span> &lt;span style="color:#268bd2">final&lt;/span> String SERVICE_NAME &lt;span style="color:#719e07">=&lt;/span> &lt;span style="color:#2aa198">&amp;#34;org.apache.dubbo.sample.tri.PbGreeter&amp;#34;&lt;/span>&lt;span style="color:#719e07">;&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#268bd2">static&lt;/span> &lt;span style="color:#268bd2">final&lt;/span> &lt;span style="color:#dc322f">boolean&lt;/span> inited &lt;span style="color:#719e07">=&lt;/span> PbGreeterDubbo&lt;span style="color:#719e07">.&lt;/span>init&lt;span style="color:#719e07">();&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#586e75">//...
&lt;/span>&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#586e75">&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> &lt;span style="color:#dc322f">void&lt;/span> &lt;span style="color:#268bd2">greetServerStream&lt;/span>&lt;span style="color:#719e07">(&lt;/span>org&lt;span style="color:#719e07">.&lt;/span>apache&lt;span style="color:#719e07">.&lt;/span>dubbo&lt;span style="color:#719e07">.&lt;/span>sample&lt;span style="color:#719e07">.&lt;/span>tri&lt;span style="color:#719e07">.&lt;/span>GreeterRequest request&lt;span style="color:#719e07">,&lt;/span> org&lt;span style="color:#719e07">.&lt;/span>apache&lt;span style="color:#719e07">.&lt;/span>dubbo&lt;span style="color:#719e07">.&lt;/span>common&lt;span style="color:#719e07">.&lt;/span>stream&lt;span style="color:#719e07">.&lt;/span>StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>org&lt;span style="color:#719e07">.&lt;/span>apache&lt;span style="color:#719e07">.&lt;/span>dubbo&lt;span style="color:#719e07">.&lt;/span>sample&lt;span style="color:#719e07">.&lt;/span>tri&lt;span style="color:#719e07">.&lt;/span>GreeterReply&lt;span style="color:#719e07">&amp;gt;&lt;/span> responseObserver&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span> org&lt;span style="color:#719e07">.&lt;/span>apache&lt;span style="color:#719e07">.&lt;/span>dubbo&lt;span style="color:#719e07">.&lt;/span>common&lt;span style="color:#719e07">.&lt;/span>stream&lt;span style="color:#719e07">.&lt;/span>StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>org&lt;span style="color:#719e07">.&lt;/span>apache&lt;span style="color:#719e07">.&lt;/span>dubbo&lt;span style="color:#719e07">.&lt;/span>sample&lt;span style="color:#719e07">.&lt;/span>tri&lt;span style="color:#719e07">.&lt;/span>GreeterRequest&lt;span style="color:#719e07">&amp;gt;&lt;/span> &lt;span style="color:#268bd2">greetStream&lt;/span>&lt;span style="color:#719e07">(&lt;/span>org&lt;span style="color:#719e07">.&lt;/span>apache&lt;span style="color:#719e07">.&lt;/span>dubbo&lt;span style="color:#719e07">.&lt;/span>common&lt;span style="color:#719e07">.&lt;/span>stream&lt;span style="color:#719e07">.&lt;/span>StreamObserver&lt;span style="color:#719e07">&amp;lt;&lt;/span>org&lt;span style="color:#719e07">.&lt;/span>apache&lt;span style="color:#719e07">.&lt;/span>dubbo&lt;span style="color:#719e07">.&lt;/span>sample&lt;span style="color:#719e07">.&lt;/span>tri&lt;span style="color:#719e07">.&lt;/span>GreeterReply&lt;span style="color:#719e07">&amp;gt;&lt;/span> responseObserver&lt;span style="color:#719e07">);&lt;/span>
&lt;/span>&lt;/span>&lt;span style="display:flex;">&lt;span>&lt;span style="color:#719e07">}&lt;/span>
&lt;/span>&lt;/span>&lt;/code>&lt;/pre>&lt;/div></description></item></channel></rss>