juneau-doc/docs/Topics/16.juneau-examples-rest/02.HelloWorldResource.html

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HelloWorldResource

<p>
	The <l>HelloWorldResource</l> class is a simple resource that prints a "Hello world!" message.
</p>

<h5 class='figure'>HelloWorldResource.java</h5>
<p class='bpcode w800'>
	<jd>/** 
	* Sample REST resource that prints out a simple "Hello world!" message. 
	*/</jd> 
	<ja>@Rest</ja>( 
		title=<js>"Hello World"</js>,
		description=<js>"An example of the simplest-possible resource"</js>,
		path=<js>"/helloWorld"</js>,
		htmldoc=<ja>@HtmlDoc</ja>(
			aside={
				<js>"&lt;div style='max-width:400px' class='text'&gt;"</js>,
				<js>"	&lt;p&gt;This page shows a resource that simply response with a 'Hello world!' message&lt;/p&gt;"</js>,
				<js>"	&lt;p&gt;The POJO serialized is a simple String.&lt;/p&gt;"</js>,
				<js>"&lt;/div&gt;"</js>
			}
		)
	) 
	<jk>public class</jk> HelloWorldResource <jk>implements</jk> BasicRestConfig { 
		
		<jd>/** GET request handler */</jd> 
		<ja>@RestMethod</ja>(name=<jsf>GET</jsf>, path=<js>"/*"</js>, summary=<js>"Responds with \"Hello world!\""</js>) 
		<jk>public</jk> String sayHello() { 
			<jk>return</jk> <js>"Hello world!"</js>; 
		} 
	}
</p>
<p>
	Notice that in this case we're not extending from {@link oajr.RestServlet}.  
	We are however implementing {@link oajr.BasicRestConfig} which is a no-op
	interface that defines a default <ja>@Rest</ja> annotation with all the serializers, parsers, 
	and configuration defined on the {@link oajr.BasicRestServlet} class.
</p>
<p>
	The only difference between implementing <l>BasicRestConfig</l> and extending from <l>BasicRestServlet</l>
	is that the latter provides the following additional features:
</p>
<ul class='spaced-list'>
	<li>A default OPTIONS method.
	<li>It can be deployed like any servlet.
</ul>
<p>
	All other examples in this project extend from <l>BasicRestServlet</l> so that they provide automatic OPTIONS page support.
</p>
<p>
	Pointing a browser to the resource shows the following:
</p>
<p class='bpcode w800'>
	http://localhost:10000/helloWorld
</p>			
<img class='bordered w800' src='doc-files/juneau-examples-rest.HelloWorldResource.1.png'>
<p>
	Using the special <l>&amp;Accept=text/json</l> and <l>&amp;plainText=true</l> parameters
		allows us to see this page rendered as JSON:
</p>		
<p class='bpcode w800'>
	http://localhost:10000/helloWorld?Accept=text/json&amp;plainText=true
</p>			
<img class='bordered w800' src='doc-files/juneau-examples-rest.HelloWorldResource.2.png'>