juneau-doc/docs/Topics/09.juneau-rest-server-springboot/02.ChildResources.html

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Child Resources

<p>
	When using the <ja>@JuneauRestRoot</ja> annotation, servlet are given an instance of {@link oajr.springboot.SpringRestResourceResolver}.  
	The resource resolver gets passed down through the children hierarchy, allowing child resources to be defined as injectable Spring beans.
</p>
<h5 class='figure'>Example:</h5>
<p class='bpcode w800'>
	<ja>@Configuration</ja>
	<jk>public class</jk> AppConfiguration {
	
		<ja>@Bean @JuneauRestRoot</ja>
		<jk>public</jk> RootResource getRootResource() {
			<jk>return new</jk> RootResource();
		}

		<ja>@Bean</ja>
		<jk>public</jk> ChildResource getChildResource() {
			<jk>return new</jk> ChildResource();
		}

		<ja>@Bean</ja>
		<jk>public</jk> GrandChildResource getGrandChildResource() {
			<jk>return new</jk> GrandChildResource(); 
		}
	}
</p>
<p>
	The root resource class must extend from <c>HttpServlet</c> so that it can be registered as a normal
	servlet using the Spring Boot architecture.  The {@link oajr.BasicRestServletGroup} class is our router class
	that extends from <c>HttpServlet</c>:
</p>
<p class='bpcode w800'>
	<ja>@RestResource</ja>(
		path=<js>"/root"</js>,
		children={
			ChildResource.<jk>class</jk>
		}
	)
	<jk>public class</jk> RootResource <jk>extends</jk> BasicRestServletGroup {
		<jc>// No code needed.</jc>
	}
</p>
<p>
	Because Spring Boot will automatically register any beans that extend from <c>HttpServlet</c>, we
	DON'T want the child classes to extend from <c>HttpServlet</c>.  Instead, we extend from
	{@link oajr.BasicRestGroup} and {@link oajr.BasicRest} instead:
</p>

<p class='bpcode w800'>
	<ja>@RestResource</ja>(
		path=<js>"/child"</js>,
		children={
			GrandChildResource.<jk>class</jk>
		}
	)
	<jk>public class</jk> ChildResource <jk>extends</jk> BasicRestGroup {
		<jc>// No code needed.</jc>
	}
</p>
<p class='bpcode w800'>
	<ja>@RestResource</ja>(
		path=<js>"/grandchild"</js>
	)
	<jk>public class</jk> GrandChildResource <jk>extends</jk> BasicRest {
		<jc>// Injectable bean</jc>
	}
</p>