Home » Enterprise Java » rest » resteasy » JSON Example With RESTEasy + Jackson

About Nikos Maravitsas

Nikos Maravitsas
Nikos has graduated from the Department of Informatics and Telecommunications of The National and Kapodistrian University of Athens. During his studies he discovered his interests about software development and he has successfully completed numerous assignments in a variety of fields. Currently, his main interests are system’s security, parallel systems, artificial intelligence, operating systems, system programming, telecommunications, web applications, human – machine interaction and mobile development.

JSON Example With RESTEasy + Jackson

In this tutorial we are going to see how you can integrate RESTEasy with Jackson to develop JAX-RS RESTful services that produce and consume JSON streams. As you probably know, Jackson is used to marshal a Java Object to JSON, and ummarshal a JSON file (or stream in general) to a Java Object

In this example we are not going to focus on how to create a JAX-RS application from top to bottom. So make sure you read carefully RESTEasy Hello World Example and pay attention to the sections concerning the creation of the project with Eclipse IDE as well as the deployment of the project in Tomcat.

You can create your own project following the instructions on RESTEasy Hello World Example. But you can also download the Eclipse project of this tutorial here : JAXRS-RESTEasy-CustomApplication.zip, and build your new code on top of that.

1. Project structure

For this example, I’ve created a new Project called “RESTEasyJSONExample“. You can see the structure of the NEW project in the image below:

project-structure

At this point you can also take a look at the web.xml file to see how the project is configured:

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"
	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>JAXRS-RESTEasy</display-name>

	<servlet-mapping>
		<servlet-name>resteasy-servlet</servlet-name>
		<url-pattern>/rest/*</url-pattern>
	</servlet-mapping>

	<!-- Auto scan REST service -->
	<context-param>
		<param-name>resteasy.scan</param-name>
		<param-value>true</param-value>
	</context-param>

	<!-- this should be the same URL pattern as the servlet-mapping property -->
	<context-param>
		<param-name>resteasy.servlet.mapping.prefix</param-name>
		<param-value>/rest</param-value>
	</context-param>

	<listener>
		<listener-class>
			org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap
			</listener-class>
	</listener>

	<servlet>
		<servlet-name>resteasy-servlet</servlet-name>
		<servlet-class>
			org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher
		</servlet-class>
	</servlet>

</web-app>

As you can see our servlet is mapped to /rest/ URI pattern. So the basic structure of the URIs to reach the REST Services used in this example will have the form :

http://localhost:8080/RESTEasyJSONExample/rest/...

2. Jackson Dependencies

To integrate RESTEasy with Jackson you have to declare the following dependencies in your pom.xml file.

JSON/Jackson Dependencies:

<dependency>
	<groupId>org.jboss.resteasy</groupId>
	<artifactId>resteasy-jackson-provider</artifactId>
	<version>3.0.4.Final</version>
</dependency>

3. Java class to be represented to JSON

This is the Java class that is going to be represented in JSON format.

Student.java:

package com.javacodegeeks.enterprise.rest.resteasy;

public class Student {

	private int id;
	private String firstName;
	private String lastName;
	private int age;

	// Must have no-argument constructor
	public Student() {

	}

	public Student(String fname, String lname, int age, int id) {
		this.firstName = fname;
		this.lastName = lname;
		this.age = age;
		this.id = id;
	}

	public void setFirstName(String fname) {
		this.firstName = fname;
	}

	public String getFirstName() {
		return this.firstName;
	}

	public void setLastName(String lname) {
		this.lastName = lname;
	}

	public String getLastName() {
		return this.lastName;
	}

	public void setAge(int age) {
		this.age = age;
	}

	public int getAge() {
		return this.age;
	}

	public void setId(int id) {
		this.id = id;
	}

	public int getId() {
		return this.id;
	}

	@Override
	public String toString() {
		return new StringBuffer(" First Name : ").append(this.firstName)
				.append(" Last Name : ").append(this.lastName)
				.append(" Age : ").append(this.age).append(" ID : ")
				.append(this.id).toString();
	}

}

4. REST Service to produce JSON output

Let’s see how easy it is with RESTEasy to produce JSON output using a simple Student instance.

RESTEasyJSONServices.java:

package com.javacodegeeks.enterprise.rest.resteasy;

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

@Path("/jsonServices")
public class RESTEasyJSONServices {

	@GET
	@Path("/print/{name}")
	@Produces("application/json")
	public Student produceJSON( @PathParam("name") String name ) {

		Student st = new Student(name, "Marco",19,12);

		return st;

	}

}

After deploying the application, open your browser and go to:

http://localhost:8080/RESTEasyJSONExample/rest/jsonServices/print/James

This is the response:

browser

Here is the raw HTTP Response:

HTTP Response:

HTTP/1.1 200 OK
Server: Apache-Coyote/1.1
Content-Type: application/json
Transfer-Encoding: chunked
Date: Sun, 08 Dec 2013 16:45:50 GMT

{"id":12,"firstName":"James","lastName":"Marco","age":19}

5. REST Service to consume JSON

Here is a REST Service that consumes a simple JSON stream. the JSON object will be parsed and unmarshaled to Student instance.

RESTEasyJSONServices.java:

package com.javacodegeeks.enterprise.rest.resteasy;

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

@Path("/jsonServices")
public class RESTEasyJSONServices {

	@POST
	@Path("/send")
	@Consumes("application/json")
	public Response consumeJSON( Student student ) {

		String output = student.toString();

		return Response.status(200).entity(output).build();
	}

}

Now in order to consume that service we have to create a post request and append an XML file to it. For that we are going to use RESTEasy Client API. To use RESTEasy Client API you have to add the following dependency in your pom.xml.

RESTEasy Client API dependency:

<dependency>
	<groupId>org.jboss.resteasy</groupId>
	<artifactId>resteasy-client</artifactId>
	<version>3.0.4.Final</version>
</dependency>

For this, I’ve created a new class, called RESTEasyClient.java in a new Package called com.javacodegeeks.enterprise.rest.resteasy.resteasyclient. So the final Project Structure would be like so:

final-project-structure

Here is the client:

RESTEasyClient.java:

package com.javacodegeeks.enterprise.rest.resteasy.resteasyclient;

import javax.ws.rs.client.Entity;
import javax.ws.rs.core.Response;

import org.jboss.resteasy.client.jaxrs.ResteasyClient;
import org.jboss.resteasy.client.jaxrs.ResteasyClientBuilder;
import org.jboss.resteasy.client.jaxrs.ResteasyWebTarget;

import com.javacodegeeks.enterprise.rest.resteasy.Student;

public class RESTEasyClient {

	public static void main(String[] args) {

		Student st = new Student("Catain", "Hook", 10, 12);

		/*
		 *  Alternatively you can use this simple String to send
		 *  instead of using a Student instance
		 *  
		 *  String jsonString = "{\"id\":12,\"firstName\":\"Catain\",\"lastName\":\"Hook\",\"age\":10}";
		 */

		try {
			ResteasyClient client = new ResteasyClientBuilder().build();

			ResteasyWebTarget target = client
					.target("http://localhost:9090/RESTEasyJSONExample/rest/jsonServices/send");

			Response response = target.request().post(
					Entity.entity(st, "application/json"));

			if (response.getStatus() != 200) {
				throw new RuntimeException("Failed : HTTP error code : "
						+ response.getStatus());
			}

			System.out.println("Server response : \n");
			System.out.println(response.readEntity(String.class));

			response.close();

		} catch (Exception e) {

			e.printStackTrace();

		}

	}
}

As you can see, we create a simple Student instance and send it to the service via a POST Request. This is the output of the above client:

Outptut:

Server response : 

First Name : Catain Last Name : Hook Age : 10 ID : 12

Here is the raw POST request:

POST Request:

POST /RESTEasyJSONExample/rest/jsonServices/send HTTP/1.1
Content-Type: application/json
Accept-Encoding: gzip, deflate
Content-Length: 57
Host: localhost:8080
Connection: Keep-Alive

{"id":12,"firstName":"Catain","lastName":"Hook","age":10}

Note: Of course you can produce your POST request using any other tool that does the job. The example will work as long as you append the appropriate code in the POST Request body, like you see in the above request. For instance, you could simply write as a String in JSON format and append it to the request.

Download Eclipse Project

This was an JSON Example With RESTEasy+ Jackson. Download the Eclipse Project of this example: RESTEasyJSONExample.zip

(No Ratings Yet)
Start the discussion Views Tweet it!

Do you want to know how to develop your skillset to become a Java Rockstar?

Subscribe to our newsletter to start Rocking right now!

To get you started we give you our best selling eBooks for FREE!

 

1. JPA Mini Book

2. JVM Troubleshooting Guide

3. JUnit Tutorial for Unit Testing

4. Java Annotations Tutorial

5. Java Interview Questions

6. Spring Interview Questions

7. Android UI Design

 

and many more ....

 

Receive Java & Developer job alerts in your Area

 

Leave a Reply

avatar
  Subscribe  
Notify of