JAX-RS Jersey Hello World beginner example -Java web services

A Simple Hello World example to know the basic jersey -RS web service

Steps:

1)Open eclipse and create a Dynamic web project with some project
name of your  choice

2) Download jersey -RS 2.0 jars from this link https://jersey.java.net/download.html

3) Go to WebContent/WEB-INF/lib folder under your project and drop all jars present under jersey folder into lib directory

4)Add the jars to the build path and add java-json.jar along with other jars to buildpath

5) Now configure web.xml (deployment descriptor) under WEB-INF as follows

  JerseyBeginner
  

    index.jsp

  
  
    HelloWorld
    org.glassfish.jersey.servlet.ServletContainer
    
      jersey.config.server.provider.packages
      com.practice.jersey
    
  
  
    HelloWorld
    /rest/*
  

Now create a package under src folder as com.practice.jersey(As given in <param-value> tags in web.xml

Create a class HelloWorld under package com.practice.jersey

Place code below in HelloWorld.java

   package com.practice.jersey;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;

import org.json.JSONException;
import org.json.JSONObject;

@Path("/hello")
public class HelloWorld {
 @GET
 @Produces(MediaType.TEXT_PLAIN)
 public String sayHello(){
  return "hello World";
 }
   
 @Path("/{name}")
 @GET
 @Produces(MediaType.TEXT_XML)
 public String toXmlHello(@PathParam("name") String name){
  return "Hello "+name+"";
 }
 
 @Path("/{name}/json")
 @GET
 @Produces(MediaType.APPLICATION_JSON)

 public Response toJsonHello(@PathParam("name") String name) throws JSONException{
  JSONObject sample=new JSONObject();  
   sample.accumulate("name", "Hello"+name);  
  return Response.status(Response.Status.ACCEPTED).entity(sample.toString()).build();
 }
}

Now run the project on server open the browser and type the Ur L's as below
1)http://localhost:8080/JerseyBeginner/rest/hello
2)http://localhost:8080/JerseyHelloWorld/rest/hello/javasimplestuff
3)http://localhost:8080/JerseyHelloWorld/rest/hello/javasimplestuff/json

output 1:   First URL calls sayHello() in HelloWorld

output2:  Second URL calls toXmlHello() in HelloWorld @Pathparam  takes the value passed from URL @Path indicates the URL pattern to call for that particular rest resouce

           

output3: Third URL calls toJsonHello()  in HelloWorld it takes path param and construct Json and returns the response