JAX-RS @Context Example

In our previous example we have learnt how to get the values using @QueryParam Annotation, now we will learn the usage of @Context annotation in getting the Query Parameters.

Folder Structure

1. Create a Dynamic Web Project RestfulExample and create a package for our src files “com.javainterviewpoint“
2. Place the required jar files under WEB-INF/Lib 
   

   jersey-bundle-1.18.jar
   asm-3.1.jar

3. Create the Java classes Context_Example.java under com.javainterviewpoint folder.
4. Place the web.xml  under the WEB-INF directory

@Context Example

import java.util.List;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.UriInfo;

@Path("/ContextExample")
public class Context_Example 
{
	@GET
	public Response getQueryParameters(@Context UriInfo uri)
	{
		String parameter1 = uri.getQueryParameters().getFirst("parameter1");
		List parameter2   = uri.getQueryParameters().get("parameter2");
		String output = "Parameter1 :"+parameter1+" Parameter2 : "+parameter2.toString();
		return Response.status(200).entity(output).build();
	}
}

Hit on the URI :
http://localhost:8080/RESTful_Example/rest/ContextExample?parameter1=”Java”&parameter2=”Interview”&parameter2=”Point”

Output

Parameter1 :"Java" Parameter2 : ["Interview", "Point"]

We have used getFirst() method to get a string and get() method to get list of strings

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:web="http://xmlns.jcp.org/xml/ns/javaee"
	xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee	
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd	
	http://java.sun.com/xml/ns/j2ee	
	http://java.sun.com/xml/ns/j2ee/web-app_2_5.xsd"
	id="WebApp_ID" version="2.5">
 <display-name>Restful Web Application</display-name>
 <servlet>
 <servlet-name>jersey-serlvet</servlet-name>
 <servlet-class>
 com.sun.jersey.spi.container.servlet.ServletContainer
 </servlet-class>
 <init-param>
 <param-name>com.sun.jersey.config.property.packages</param-name>
 <param-value>com.javainterviewpoint</param-value>
 </init-param>
 
 <load-on-startup>1</load-on-startup>
 </servlet>
 <servlet-mapping>
 <servlet-name>jersey-serlvet</servlet-name>
 <url-pattern>/rest/*</url-pattern>
 </servlet-mapping>
</web-app>

We register our jersey container “com.sun.jersey.spi.container.servlet.ServletContainer” in the servlet-class of our web.xml and we will mention the source files location as the value to the init param “com.sun.jersey.config.property.packages” so that the container will scan for annotations of the class files within that package.