JAX-RS to Consume JSON using Jackson

In this tutorial we are going to see how to consume JSON type input using RESTful web service and Jackson
1. Create new Dynamic web project by choosing File –> New –> Dynamic Web Project .
2. Create the Project called RESTful-WebService
3. Add the following jar into WEF-INF/lib folder

4. Create package called com.javatutorialscorner.jaxrs.jsonservice under RESTful-WebService
5. Create Java class JSONService1 under com.javatutorialscorner.jaxrs.jsonservice package
JSONService1.java

package com.javatutorialscorner.jaxrs.jsonservice;
 
import javax.ws.rs.Consumes;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
 
 
@Path("consumejson")
public class JSONService1 {
 
 @POST
 @Path("post")
 @Consumes(MediaType.APPLICATION_JSON)
 public Response setStudentDetail(Student student){
  String response = "Data Received Successfuly : "+student.getName();
  return Response.status(201).entity(response).build();  
 }
}

In above program Jackson used to convert JSON to object. Jersey uses the @Consumes(MediaType.APPLICATION_JSON) annotation will convert JSON into object automatically.For this conversion jersey-json.jar is required.

6. Create Java class Student under com.javatutorialscorner.jaxrs.jsonservice package
Student.java

package com.javatutorialscorner.jaxrs.jsonservice;
 
public class Student {
 
 String name;
 int id;
 String department;
 int year;
 
 public String getName() {
  return name;
 }
 
 public void setName(String name) {
  this.name = name;
 }
 
 public int getId() {
  return id;
 }
 
 public void setId(int id) {
  this.id = id;
 }
 
 public String getDepartment() {
  return department;
 }
 
 public void setDepartment(String department) {
  this.department = department;
 }
 
 public int getYear() {
  return year;
 }
 
 public void setYear(int year) {
  this.year = year;
 }
 
}

Jersey Jackson convert JSON input to this class type object.

7.Configure Jersey Servlet Dispatcher
you need to configure REST as servlet in web.xml.
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/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>JAX-RS-Path</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.javatutorialscorner.jaxrs.jsonservice</param-value>
  </init-param>
  <init-param>
  <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
  <param-value>true</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>

The servlet class available in jersey com.sun.jersey.spi.container.servlet.ServletContainer. The init param com.sun.jersey.config.property.package is used to define in which package jersey will look for the service classes.This package points to your resource class package. URL pattern is the part of base URL

<init-param>
  <param-name>com.sun.jersey.api.json.POJOMappingFeature</param-name>
  <param-value>true</param-value>
 </init-param>

In this web.xml above lines are additionally added for Jersey to Support JSON-Object mapping.

you can call the service by using from client class.

Create Client

Create package called com.javatutorialscorner.jaxrs.client under RESTful-WebService project
Create Client Java Class RESTfulClient under com.javatutorialscorner.jaxrs.client package

RESTfulClient .java

package com.javatutorialscorner.jaxrs.client;
 
import com.sun.jersey.api.client.Client;
import com.sun.jersey.api.client.ClientResponse;
import com.sun.jersey.api.client.WebResource;
import com.sun.jersey.api.client.config.ClientConfig;
import com.sun.jersey.api.client.config.DefaultClientConfig;
 
public class RESTfulClient {
 
 /**
  * @param args
  */
 public static void main(String[] args) {
  // TODO Auto-generated method stub
  try {
   String baseURI = "http://localhost:8080/RESTful-WebService/rest/consumejson/post";
   ClientConfig config = new DefaultClientConfig();
   Client client = Client.create(config);
   WebResource service = client.resource(baseURI);
   String json = "{\"name\":\"Ram\",\"id\":33,\"department\":\"EEE\",\"year\":2011}";
   ClientResponse response = service.type("application/json").post(
     ClientResponse.class, json);
   System.out.println("output for JSON Service ");
 
   if (response.getStatus() != 201) {
    throw new Exception("Error code : " + response.getStatus());
   }
 
   System.out.println("output " + response.getEntity(String.class));
  } catch (Exception e) {
   e.printStackTrace();
  }
 }
 
}