Dinesh on Java

In this tutorial, We are going to show you how to develop RESTful services with Jersey and how to deploy them on a Tomcat server. The RESTful approach of developing web services is constantly gaining more and more attention and seems to be pushing SOAP into deprecation.Now the follow the following steps to build the JAX-RS web service with Jersey and deploy to Tomcat7.

Technologies and Tools used in this article:

• Jersey 2.0
• JDK 1.7
• Tomcat 7.0
• STS 2.7

Step 1) Create Dynamic Web Application “RESTWebApp“.

Step 2) Create web.xml (deployment descriptor) under WebRootWEB-INF .

Step 3) Open web.xml file and add below code just above :

<?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/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>RESTWebApp</display-name>
 <servlet>
  <servlet-name>jersey-serlvet</servlet-name>
  <servlet-class>
         com.sun.jersey.spi.container.servlet.ServletContainer
        </servlet-class>
  <load-on-startup>1</load-on-startup>
 </servlet>
 
 <servlet-mapping>
  <servlet-name>jersey-serlvet</servlet-name>
  <url-pattern>/doj/*</url-pattern>
 </servlet-mapping>
</web-app>

Step 4) Adding two jars file You can download from here: asm-3.3.1.jar, jersey-bundle-1.14.jar

Step 5) Creating Employee bean class
Employee.java

package com.dineshonjava.ws.rest.bean;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;

/**
 * @author Dinesh Rajput
 *
 */

@XmlRootElement(name = "employee")
public class Employee {
 private String employeeId;
    private String employeeName;
    private String jobType;
    private String address;
    private Long salary;
    
    @XmlElement
    public String getEmployeeId() {
        return employeeId;
    }
    
    public void setEmployeeId(String employeeId) {
        this.employeeId = employeeId;
    }
    
    @XmlElement
    public String getEmployeeName() {
        return employeeName;
    }
    
    public void setEmployeeName(String employeeName) {
        this.employeeName = employeeName;
    }

    @XmlElement
 public String getAddress() {
  return address;
 }

 public void setAddress(String address) {
  this.address = address;
 }

 @XmlElement
 public Long getSalary() {
  return salary;
 }

 public void setSalary(Long salary) {
  this.salary = salary;
 }

 @XmlElement
 public String getJobType() {
  return jobType;
 }

 public void setJobType(String jobType) {
  this.jobType = jobType;
 }
       
}

Step 6) Create WebController.java file

package com.dineshonjava.ws.rest;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;

import com.dineshonjava.ws.rest.bean.Employee;

/**
 * @author Dinesh Rajput
 *
 */

@Path("/webservice")
public class WebController {
 
  private static Map<String, Employee> employees = new HashMap<String, Employee>();
     
     static {
         
         Employee employee1 = new Employee();
         employee1.setEmployeeId("11111");
         employee1.setEmployeeName("Dineh Rajput");
         employee1.setJobType("Sr.Software Engineer");
         employee1.setSalary(70000l);
         employee1.setAddress("Noida");
         employees.put(employee1.getEmployeeId(), employee1);
         
         Employee employee2 = new Employee();
         employee2.setEmployeeId("22222");
         employee2.setEmployeeName("Abhishek");
         employee2.setJobType("Marketing");
         employee2.setSalary(50000l);
         employee2.setAddress("New Delhi");
         employees.put(employee2.getEmployeeId(), employee2);
         
     }

     @GET
     @Path("/hello")
     @Produces("text/plain")
     public String hello(){
         return "Hello World!!! dineshonjava";    
     }
     
     @GET
     @Path("/message/{message}")
     @Produces("text/plain")
     public String showMsg(@PathParam("message") String message){
         return message;    
     }
     
     @GET
     @Path("/employees")
     @Produces("application/xml")
     public List<Employee> listEmployees(){
         return new ArrayList<Employee>(employees.values());
     }
     
     @GET
     @Path("/employee/{employeeid}")
     @Produces("application/xml")
     public Employee getEmployee(@PathParam("employeeid")String employeeId){
         return employees.get(employeeId);        
     }
     
     @GET
     @Path("/json/employees/")
     @Produces("application/json")
     public List<Employee> listEmployeesJSON(){
         return new ArrayList<Employee>(employees.values());
     }

     @GET
     @Path("/json/employee/{employeeid}")
     @Produces("application/json")
     public Employee getEmployeeJSON(@PathParam("employeeid")String employeeId){
         return employees.get(employeeId);        
     }
  
}

Step 7) Deploy project “RESTWebApp” on Tomcat7. Web project should be deployed without any exception.

Step 8) If every thing fine then test it now following link.
http://localhost:8181/sdnext/doj/webservice/hello

http://localhost:8181/sdnext/doj/webservice/message/Welcome%20to%20DineshOnJava.com

http://localhost:8181/sdnext/doj/webservice/employees

http://localhost:8181/sdnext/doj/webservice/employee/11111

http://localhost:8181/sdnext/doj/webservice/json/employees

 http://localhost:8181/sdnext/doj/webservice/json/employee/11111

Download Source Code + Libs
RESTWebApp.zip

References
1. JAVA REST Web Services
2. Wikipedia for REST Web Service