@context

@Context injects information into Class field or a method parameter. 

Provides Access to ServletConfig, ServletContext, HTTPServletRequest, HTTPServletResponse


Method Parameter injection example with HTTPServletRequest

import java.util.HashMap;

import javax.servlet.http.HttpServletRequest;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import com.fasterxml.jackson.databind.ObjectMapper;

@Path("sandbox")
public class Sandbox {

	ObjectMapper mapper = new ObjectMapper();
	
	@POST
	@Produces(MediaType.TEXT_PLAIN)
	public Response getIt(@Context HttpServletRequest request) {
		try {
			HashMap<String, Object> hm = new HashMap<String, Object>();
			hm.put("Content Length", request.getContentLength());
			hm.put("Content Type", request.getContentType());
			hm.put("Character Encoding", request.getCharacterEncoding());
			hm.put("Local Address", request.getLocalAddr());
			hm.put("Parameter Map", request.getParameterMap());
			return Response.status(Response.Status.OK).entity(mapper.writeValueAsString(hm)).build();
		} catch (Exception e) {
			e.printStackTrace();
			return Response.status(Response.Status.BAD_REQUEST)
					.entity("Error").build();
		}
	}
}

Class Field Injection Example with ServletContext

package test;

import java.util.Enumeration;
import java.util.HashMap;

import javax.servlet.ServletContext;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import com.fasterxml.jackson.databind.ObjectMapper;

@Path("sandbox")
public class Sandbox {

	@Context ServletContext contxt;
	
	ObjectMapper mapper = new ObjectMapper();

	@POST
	@Produces(MediaType.TEXT_PLAIN)
	
	public Response getIt() {
		try {
			HashMap<String, Object> hm = new HashMap(<String, Object> );
			hm.put("Context Path", contxt.getContextPath());
			hm.put("Major Version", contxt.getEffectiveMajorVersion());
			hm.put("Servlet Info", contxt.getServerInfo());
			Enumeration<String> en = contxt.getInitParameterNames();
			while (en.hasMoreElements()) {
				String name = (String) en.nextElement();
				System.out.println(name + "." + contxt.getInitParameter(name));
			}
			return Response.status(Response.Status.OK)
					.entity(mapper.writeValueAsString(hm)).build();
		} catch (Exception e) {
			e.printStackTrace();
			return Response.status(Response.Status.BAD_REQUEST).entity("Error")
					.build();
		}
	}
}

Calss Feild Injection with UriInfo

package test;

import java.util.HashMap;

import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.Context;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.UriInfo;

import com.fasterxml.jackson.databind.ObjectMapper;

@Path("sandbox")
public class Sandbox {

	@Context
	UriInfo uriinfo;

	ObjectMapper mapper = new ObjectMapper();

	@POST
	@Produces(MediaType.TEXT_PLAIN)
	public Response getIt() {
		try {
			HashMap<String, Object> hm = new HashMap<String, Object>();
			hm.put("Absolute Path", uriinfo.getAbsolutePath().getPath());
			hm.put("Request URI", uriinfo.getRequestUri());
			hm.put("Path Segments", uriinfo.getPathSegments());
			hm.put("Query Parameters", uriinfo.getQueryParameters());
			return Response.status(Response.Status.OK)
					.entity(mapper.writeValueAsString(hm)).build();
		} catch (Exception e) {
			e.printStackTrace();
			return Response.status(Response.Status.BAD_REQUEST).entity("Error")
					.build();
		}
	}
}