(window.webpackJsonp=window.webpackJsonp||[]).push([[463],{860:function(t,s,a){"use strict";a.r(s);var n=a(29),e=Object(n.a)({},(function(){var t=this,s=t._self._c;return s("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[s("h2",{attrs:{id:"mqtt-协议"}},[s("a",{staticClass:"header-anchor",attrs:{href:"#mqtt-协议"}},[t._v("#")]),t._v(" MQTT 协议")]),t._v(" "),s("p",[s("a",{attrs:{href:"http://mqtt.org/",target:"_blank",rel:"noopener noreferrer"}},[t._v("MQTT"),s("OutboundLink")],1),t._v(" 是机器对机器（M2M）/“物联网”连接协议。")]),t._v(" "),s("p",[t._v("它被设计为一种非常轻量级的发布/订阅消息传递。")]),t._v(" "),s("p",[t._v("对于与需要较小代码占用和/或网络带宽非常宝贵的远程位置的连接很有用。")]),t._v(" "),s("p",[t._v("IoTDB 支持 MQTT v3.1（OASIS 标准）协议。\nIoTDB 服务器包括内置的 MQTT 服务，该服务允许远程设备将消息直接发送到 IoTDB 服务器。")]),t._v(" "),s("img",{staticStyle:{width:"100%","max-width":"800px","max-height":"600px","margin-left":"auto","margin-right":"auto",display:"block"},attrs:{src:"https://user-images.githubusercontent.com/6711230/78357432-0c71cf80-75e4-11ea-98aa-c43a54d469ce.png"}}),t._v(" "),s("h3",{attrs:{id:"内置-mqtt-服务"}},[s("a",{staticClass:"header-anchor",attrs:{href:"#内置-mqtt-服务"}},[t._v("#")]),t._v(" 内置 MQTT 服务")]),t._v(" "),s("p",[t._v("内置的 MQTT 服务提供了通过 MQTT 直接连接到 IoTDB 的能力。 它侦听来自 MQTT 客户端的发布消息，然后立即将数据写入存储。\nMQTT 主题与 IoTDB 时间序列相对应。\n消息有效载荷可以由 Java SPI 加载的"),s("code",[t._v("PayloadFormatter")]),t._v("格式化为事件，默认实现为"),s("code",[t._v("JSONPayloadFormatter")]),t._v("\n默认的"),s("code",[t._v("json")]),t._v("格式化程序支持两种 json 格式以及由他们组成的json数组，以下是 MQTT 消息有效负载示例：")]),t._v(" "),s("div",{staticClass:"language-json line-numbers-mode"},[s("pre",{pre:!0,attrs:{class:"language-json"}},[s("code",[t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n      "),s("span",{pre:!0,attrs:{class:"token property"}},[t._v('"device"')]),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"root.sg.d1"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n      "),s("span",{pre:!0,attrs:{class:"token property"}},[t._v('"timestamp"')]),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("1586076045524")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n      "),s("span",{pre:!0,attrs:{class:"token property"}},[t._v('"measurements"')]),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"s1"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"s2"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n      "),s("span",{pre:!0,attrs:{class:"token property"}},[t._v('"values"')]),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("0.530635")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("0.530635")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])]),t._v(" "),s("div",{staticClass:"line-numbers-wrapper"},[s("span",{staticClass:"line-number"},[t._v("1")]),s("br"),s("span",{staticClass:"line-number"},[t._v("2")]),s("br"),s("span",{staticClass:"line-number"},[t._v("3")]),s("br"),s("span",{staticClass:"line-number"},[t._v("4")]),s("br"),s("span",{staticClass:"line-number"},[t._v("5")]),s("br"),s("span",{staticClass:"line-number"},[t._v("6")]),s("br")])]),s("p",[t._v("或者")]),t._v(" "),s("div",{staticClass:"language-json line-numbers-mode"},[s("pre",{pre:!0,attrs:{class:"language-json"}},[s("code",[t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n      "),s("span",{pre:!0,attrs:{class:"token property"}},[t._v('"device"')]),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"root.sg.d1"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n      "),s("span",{pre:!0,attrs:{class:"token property"}},[t._v('"timestamps"')]),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("1586076045524")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("1586076065526")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n      "),s("span",{pre:!0,attrs:{class:"token property"}},[t._v('"measurements"')]),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"s1"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"s2"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n      "),s("span",{pre:!0,attrs:{class:"token property"}},[t._v('"values"')]),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v(":")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("0.530635")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("0.530635")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("[")]),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("0.530655")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("0.530695")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("]")]),t._v("\n "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])]),t._v(" "),s("div",{staticClass:"line-numbers-wrapper"},[s("span",{staticClass:"line-number"},[t._v("1")]),s("br"),s("span",{staticClass:"line-number"},[t._v("2")]),s("br"),s("span",{staticClass:"line-number"},[t._v("3")]),s("br"),s("span",{staticClass:"line-number"},[t._v("4")]),s("br"),s("span",{staticClass:"line-number"},[t._v("5")]),s("br"),s("span",{staticClass:"line-number"},[t._v("6")]),s("br")])]),s("p",[t._v("或者以上两者的JSON数组形式。")]),t._v(" "),s("img",{staticStyle:{width:"100%","max-width":"800px","max-height":"600px","margin-left":"auto","margin-right":"auto",display:"block"},attrs:{src:"https://user-images.githubusercontent.com/6711230/78357469-1bf11880-75e4-11ea-978f-a53996667a0d.png"}}),t._v(" "),s("h3",{attrs:{id:"mqtt-配置"}},[s("a",{staticClass:"header-anchor",attrs:{href:"#mqtt-配置"}},[t._v("#")]),t._v(" MQTT 配置")]),t._v(" "),s("p",[t._v("默认情况下，IoTDB MQTT 服务从"),s("code",[t._v("${IOTDB_HOME}/${IOTDB_CONF}/iotdbengine.properties")]),t._v("加载配置。")]),t._v(" "),s("p",[t._v("配置如下：")]),t._v(" "),s("table",[s("thead",[s("tr",[s("th",[t._v("名称")]),t._v(" "),s("th",{staticStyle:{"text-align":"center"}},[t._v("描述")]),t._v(" "),s("th",{staticStyle:{"text-align":"center"}},[t._v("默认")])])]),t._v(" "),s("tbody",[s("tr",[s("td",[t._v("enable_mqtt_service")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("是否启用 mqtt 服务")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("false")])]),t._v(" "),s("tr",[s("td",[t._v("mqtt_host")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("mqtt 服务绑定主机")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("0.0.0.0")])]),t._v(" "),s("tr",[s("td",[t._v("mqtt_port")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("mqtt 服务绑定端口")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("1883")])]),t._v(" "),s("tr",[s("td",[t._v("mqtt_handler_pool_size")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("处理 mqtt 消息的处理程序池大小")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("1")])]),t._v(" "),s("tr",[s("td",[t._v("mqtt_payload_formatter")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("mqtt 消息有效负载格式化程序")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("json")])]),t._v(" "),s("tr",[s("td",[t._v("mqtt_max_message_size")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("mqtt 消息最大长度（字节）")]),t._v(" "),s("td",{staticStyle:{"text-align":"center"}},[t._v("1048576")])])])]),t._v(" "),s("p",[t._v("### 示例代码\n以下是 mqtt 客户端将消息发送到 IoTDB 服务器的示例。")]),t._v(" "),s("div",{staticClass:"language-java line-numbers-mode"},[s("pre",{pre:!0,attrs:{class:"language-java"}},[s("code",[s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("MQTT")]),t._v(" mqtt "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("new")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("MQTT")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\nmqtt"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("setHost")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"127.0.0.1"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("1883")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\nmqtt"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("setUserName")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"root"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\nmqtt"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("setPassword")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"root"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("BlockingConnection")]),t._v(" connection "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" mqtt"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("blockingConnection")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\nconnection"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("connect")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Random")]),t._v(" random "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("new")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Random")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("for")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("int")]),t._v(" i "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" i "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("10")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" i"),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("++")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n   "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),t._v(" payload "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("format")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"{\\n"')]),t._v(" "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v("\n           "),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"\\"device\\":\\"root.sg.d1\\",\\n"')]),t._v(" "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v("\n           "),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"\\"timestamp\\":%d,\\n"')]),t._v(" "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v("\n           "),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"\\"measurements\\":[\\"s1\\"],\\n"')]),t._v(" "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v("\n           "),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"\\"values\\":[%f]\\n"')]),t._v(" "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v("\n           "),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"}"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("System")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("currentTimeMillis")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" random"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("nextDouble")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n   connection"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("publish")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"root.sg.d1.s1"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" payload"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("getBytes")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("QoS")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("AT_LEAST_ONCE"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token boolean"}},[t._v("false")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\nconnection"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("disconnect")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n")])]),t._v(" "),s("div",{staticClass:"line-numbers-wrapper"},[s("span",{staticClass:"line-number"},[t._v("1")]),s("br"),s("span",{staticClass:"line-number"},[t._v("2")]),s("br"),s("span",{staticClass:"line-number"},[t._v("3")]),s("br"),s("span",{staticClass:"line-number"},[t._v("4")]),s("br"),s("span",{staticClass:"line-number"},[t._v("5")]),s("br"),s("span",{staticClass:"line-number"},[t._v("6")]),s("br"),s("span",{staticClass:"line-number"},[t._v("7")]),s("br"),s("span",{staticClass:"line-number"},[t._v("8")]),s("br"),s("span",{staticClass:"line-number"},[t._v("9")]),s("br"),s("span",{staticClass:"line-number"},[t._v("10")]),s("br"),s("span",{staticClass:"line-number"},[t._v("11")]),s("br"),s("span",{staticClass:"line-number"},[t._v("12")]),s("br"),s("span",{staticClass:"line-number"},[t._v("13")]),s("br"),s("span",{staticClass:"line-number"},[t._v("14")]),s("br"),s("span",{staticClass:"line-number"},[t._v("15")]),s("br"),s("span",{staticClass:"line-number"},[t._v("16")]),s("br"),s("span",{staticClass:"line-number"},[t._v("17")]),s("br"),s("span",{staticClass:"line-number"},[t._v("18")]),s("br"),s("span",{staticClass:"line-number"},[t._v("19")]),s("br"),s("span",{staticClass:"line-number"},[t._v("20")]),s("br"),s("span",{staticClass:"line-number"},[t._v("21")]),s("br")])]),s("h3",{attrs:{id:"自定义-mqtt-消息格式"}},[s("a",{staticClass:"header-anchor",attrs:{href:"#自定义-mqtt-消息格式"}},[t._v("#")]),t._v(" 自定义 MQTT 消息格式")]),t._v(" "),s("p",[t._v("事实上可以通过简单编程来实现 MQTT 消息的格式自定义。\n可以在源码的 "),s("code",[t._v("example/mqtt-customize")]),t._v(" 项目中找到一个简单示例。")]),t._v(" "),s("p",[t._v("步骤:")]),t._v(" "),s("ul",[s("li",[t._v("创建一个 Java 项目，增加如下依赖")])]),t._v(" "),s("div",{staticClass:"language-xml line-numbers-mode"},[s("pre",{pre:!0,attrs:{class:"language-xml"}},[s("code",[t._v("        "),s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),t._v("dependency")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v("\n            "),s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),t._v("groupId")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v("org.apache.iotdb"),s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("</")]),t._v("groupId")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v("\n            "),s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),t._v("artifactId")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v("iotdb-server"),s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("</")]),t._v("artifactId")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v("\n            "),s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),t._v("version")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v("0.14.0-SNAPSHOT"),s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("</")]),t._v("version")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token tag"}},[s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("</")]),t._v("dependency")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v("\n")])]),t._v(" "),s("div",{staticClass:"line-numbers-wrapper"},[s("span",{staticClass:"line-number"},[t._v("1")]),s("br"),s("span",{staticClass:"line-number"},[t._v("2")]),s("br"),s("span",{staticClass:"line-number"},[t._v("3")]),s("br"),s("span",{staticClass:"line-number"},[t._v("4")]),s("br"),s("span",{staticClass:"line-number"},[t._v("5")]),s("br")])]),s("ul",[s("li",[t._v("创建一个实现类，实现接口 "),s("code",[t._v("org.apache.iotdb.db.mqtt.PayloadFormatter.java")])])]),t._v(" "),s("div",{staticClass:"language-java line-numbers-mode"},[s("pre",{pre:!0,attrs:{class:"language-java"}},[s("code",[s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("package")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token namespace"}},[t._v("org"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("apache"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("iotdb"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("mqtt"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("server")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token import"}},[s("span",{pre:!0,attrs:{class:"token namespace"}},[t._v("io"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("netty"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("buffer"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")])]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("ByteBuf")])]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token import"}},[s("span",{pre:!0,attrs:{class:"token namespace"}},[t._v("org"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("apache"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("iotdb"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("db"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("protocol"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("mqtt"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")])]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Message")])]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token import"}},[s("span",{pre:!0,attrs:{class:"token namespace"}},[t._v("org"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("apache"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("iotdb"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("db"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("protocol"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("mqtt"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")])]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("PayloadFormatter")])]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token import"}},[s("span",{pre:!0,attrs:{class:"token namespace"}},[t._v("java"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("nio"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("charset"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")])]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("StandardCharsets")])]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token import"}},[s("span",{pre:!0,attrs:{class:"token namespace"}},[t._v("java"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("util"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")])]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("ArrayList")])]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token import"}},[s("span",{pre:!0,attrs:{class:"token namespace"}},[t._v("java"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("util"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")])]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Arrays")])]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n"),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("import")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token import"}},[s("span",{pre:!0,attrs:{class:"token namespace"}},[t._v("java"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("util"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")])]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("List")])]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n\n"),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("class")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("CustomizedJsonPayloadFormatter")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("implements")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("PayloadFormatter")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n\n    "),s("span",{pre:!0,attrs:{class:"token annotation punctuation"}},[t._v("@Override")]),t._v("\n    "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("List")]),s("span",{pre:!0,attrs:{class:"token generics"}},[s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Message")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" "),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("format")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("ByteBuf")]),t._v(" payload"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// Suppose the payload is a json format")]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("if")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("payload "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("==")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("null")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n            "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("return")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("null")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n        "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),t._v(" json "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" payload"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("toString")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("StandardCharsets")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),t._v("UTF_8"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// parse data from the json and generate Messages and put them into List<Meesage> ret")]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("List")]),s("span",{pre:!0,attrs:{class:"token generics"}},[s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Message")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),t._v(" ret "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("new")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("ArrayList")]),s("span",{pre:!0,attrs:{class:"token generics"}},[s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("<")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(">")])]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// this is just an example, so we just generate some Messages directly")]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("for")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("int")]),t._v(" i "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("0")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" i "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token number"}},[t._v("2")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v(" i"),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("++")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n            "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("long")]),t._v(" ts "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" i"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Message")]),t._v(" message "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("=")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("new")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Message")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            message"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("setDevice")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"d"')]),t._v(" "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v(" i"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            message"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("setTimestamp")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("ts"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            message"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("setMeasurements")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Arrays")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("asList")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"s1"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"s2"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            message"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("setValues")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Arrays")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("asList")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"4.0"')]),t._v(" "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v(" i"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"5.0"')]),t._v(" "),s("span",{pre:!0,attrs:{class:"token operator"}},[t._v("+")]),t._v(" i"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n            ret"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(".")]),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("add")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("message"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("return")]),t._v(" ret"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n\n    "),s("span",{pre:!0,attrs:{class:"token annotation punctuation"}},[t._v("@Override")]),t._v("\n    "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("public")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("String")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token function"}},[t._v("getName")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("{")]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// set the value of mqtt_payload_formatter in iotdb-datanode.properties as the following string:")]),t._v("\n        "),s("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("return")]),t._v(" "),s("span",{pre:!0,attrs:{class:"token string"}},[t._v('"CustomizedJson"')]),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(";")]),t._v("\n    "),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n"),s("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("}")]),t._v("\n")])]),t._v(" "),s("div",{staticClass:"line-numbers-wrapper"},[s("span",{staticClass:"line-number"},[t._v("1")]),s("br"),s("span",{staticClass:"line-number"},[t._v("2")]),s("br"),s("span",{staticClass:"line-number"},[t._v("3")]),s("br"),s("span",{staticClass:"line-number"},[t._v("4")]),s("br"),s("span",{staticClass:"line-number"},[t._v("5")]),s("br"),s("span",{staticClass:"line-number"},[t._v("6")]),s("br"),s("span",{staticClass:"line-number"},[t._v("7")]),s("br"),s("span",{staticClass:"line-number"},[t._v("8")]),s("br"),s("span",{staticClass:"line-number"},[t._v("9")]),s("br"),s("span",{staticClass:"line-number"},[t._v("10")]),s("br"),s("span",{staticClass:"line-number"},[t._v("11")]),s("br"),s("span",{staticClass:"line-number"},[t._v("12")]),s("br"),s("span",{staticClass:"line-number"},[t._v("13")]),s("br"),s("span",{staticClass:"line-number"},[t._v("14")]),s("br"),s("span",{staticClass:"line-number"},[t._v("15")]),s("br"),s("span",{staticClass:"line-number"},[t._v("16")]),s("br"),s("span",{staticClass:"line-number"},[t._v("17")]),s("br"),s("span",{staticClass:"line-number"},[t._v("18")]),s("br"),s("span",{staticClass:"line-number"},[t._v("19")]),s("br"),s("span",{staticClass:"line-number"},[t._v("20")]),s("br"),s("span",{staticClass:"line-number"},[t._v("21")]),s("br"),s("span",{staticClass:"line-number"},[t._v("22")]),s("br"),s("span",{staticClass:"line-number"},[t._v("23")]),s("br"),s("span",{staticClass:"line-number"},[t._v("24")]),s("br"),s("span",{staticClass:"line-number"},[t._v("25")]),s("br"),s("span",{staticClass:"line-number"},[t._v("26")]),s("br"),s("span",{staticClass:"line-number"},[t._v("27")]),s("br"),s("span",{staticClass:"line-number"},[t._v("28")]),s("br"),s("span",{staticClass:"line-number"},[t._v("29")]),s("br"),s("span",{staticClass:"line-number"},[t._v("30")]),s("br"),s("span",{staticClass:"line-number"},[t._v("31")]),s("br"),s("span",{staticClass:"line-number"},[t._v("32")]),s("br"),s("span",{staticClass:"line-number"},[t._v("33")]),s("br"),s("span",{staticClass:"line-number"},[t._v("34")]),s("br"),s("span",{staticClass:"line-number"},[t._v("35")]),s("br"),s("span",{staticClass:"line-number"},[t._v("36")]),s("br"),s("span",{staticClass:"line-number"},[t._v("37")]),s("br"),s("span",{staticClass:"line-number"},[t._v("38")]),s("br"),s("span",{staticClass:"line-number"},[t._v("39")]),s("br"),s("span",{staticClass:"line-number"},[t._v("40")]),s("br"),s("span",{staticClass:"line-number"},[t._v("41")]),s("br"),s("span",{staticClass:"line-number"},[t._v("42")]),s("br")])]),s("ul",[s("li",[t._v("修改项目中的 "),s("code",[t._v("src/main/resources/META-INF/services/org.apache.iotdb.db.mqtt.PayloadFormatter")]),t._v(" 文件:\n将示例中的文件内容清除，并将刚才的实现类的全名（包名.类名）写入文件中。注意，这个文件中只有一行。\n在本例中，文件内容为: "),s("code",[t._v("org.apache.iotdb.mqtt.server.CustomizedJsonPayloadFormatter")])]),t._v(" "),s("li",[t._v("编译项目生成一个 jar 包: "),s("code",[t._v("mvn package -DskipTests")])])]),t._v(" "),s("p",[t._v("在 IoTDB 服务端:")]),t._v(" "),s("ul",[s("li",[t._v("创建 ${IOTDB_HOME}/ext/mqtt/ 文件夹, 将刚才的 jar 包放入此文件夹。")]),t._v(" "),s("li",[t._v("打开 MQTT 服务参数. ("),s("code",[t._v("enable_mqtt_service=true")]),t._v(" in "),s("code",[t._v("conf/iotdb-datanode.properties")]),t._v(")")]),t._v(" "),s("li",[t._v("用刚才的实现类中的 getName() 方法的返回值 设置为 "),s("code",[t._v("conf/iotdb-datanode.properties")]),t._v(" 中 "),s("code",[t._v("mqtt_payload_formatter")]),t._v(" 的值，\n, 在本例中，为 "),s("code",[t._v("CustomizedJson")])]),t._v(" "),s("li",[t._v("启动 IoTDB")]),t._v(" "),s("li",[t._v("搞定.")])]),t._v(" "),s("p",[t._v("More: MQTT 协议的消息不限于 json，你还可以用任意二进制。通过如下函数获得：\n"),s("code",[t._v("payload.forEachByte()")]),t._v(" or "),s("code",[t._v("payload.array")]),t._v("。")])])}),[],!1,null,null,null);s.default=e.exports}}]);