August 14, 2022

RESTful Java client with RESTEasy client framework

This tutorial show you how to create a RESTful Java client with RESTEasy client framework, to perform “GET” and “POST” requests to REST service that created in last “Jackson + JAX-RS” tutorial.

1. RESTEasy Client Framework

RESTEasy client framework is included in RESTEasy core module, so, you just need to declares the “resteasy-jaxrs.jar” in your pom.xml file.

File : pom.xml

	<dependency>
		<groupId>org.jboss.resteasy</groupId>
		<artifactId>resteasy-jaxrs</artifactId>
		<version>2.2.1.GA</version>
	</dependency>

2. GET Request

Review last REST service.

@Path("/json/product")
public class JSONService {

	@GET
	@Path("/get")
	@Produces("application/json")
	public Product getProductInJSON() {

		Product product = new Product();
		product.setName("iPad 3");
		product.setQty(999);
		
		return product; 

	}
	//...

RESTEasy client to send a “GET” request.

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import org.apache.http.client.ClientProtocolException;
import org.jboss.resteasy.client.ClientRequest;
import org.jboss.resteasy.client.ClientResponse;

public class RESTEasyClientGet {

	public static void main(String[] args) {
	  try {

		ClientRequest request = new ClientRequest(
				"http://localhost:8080/RESTfulExample/json/product/get");
		request.accept("application/json");
		ClientResponse<String> response = request.get(String.class);

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

		BufferedReader br = new BufferedReader(new InputStreamReader(
			new ByteArrayInputStream(response.getEntity().getBytes())));

		String output;
		System.out.println("Output from Server .... \n");
		while ((output = br.readLine()) != null) {
			System.out.println(output);
		}

	  } catch (ClientProtocolException e) {

		e.printStackTrace();

	  } catch (IOException e) {

		e.printStackTrace();

	  } catch (Exception e) {

		e.printStackTrace();

	  }

	}

}

Output…

Output from Server .... 

{"qty":999,"name":"iPad 3"}

3. POST Request

Review last REST service also.

@Path("/json/product")
public class JSONService {

        @POST
	@Path("/post")
	@Consumes("application/json")
	public Response createProductInJSON(Product product) {

		String result = "Product created : " + product;
		return Response.status(201).entity(result).build();
		
	}
	//...

RESTEasy client to send a “POST” request.

import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import org.jboss.resteasy.client.ClientRequest;
import org.jboss.resteasy.client.ClientResponse;

public class RESTEasyClientPost {

	public static void main(String[] args) {

	  try {

		ClientRequest request = new ClientRequest(
			"http://localhost:8080/RESTfulExample/json/product/post");
		request.accept("application/json");

		String input = "{\"qty\":100,\"name\":\"iPad 4\"}";
		request.body("application/json", input);
			
		ClientResponse<String> response = request.post(String.class);

		if (response.getStatus() != 201) {
			throw new RuntimeException("Failed : HTTP error code : "
				+ response.getStatus());
		}

		BufferedReader br = new BufferedReader(new InputStreamReader(
			new ByteArrayInputStream(response.getEntity().getBytes())));

		String output;
		System.out.println("Output from Server .... \n");
		while ((output = br.readLine()) != null) {
			System.out.println(output);
		}

	  } catch (MalformedURLException e) {

		e.printStackTrace();
			
	  } catch (IOException e) {

		e.printStackTrace();

	  } catch (Exception e) {

		e.printStackTrace();

	  }

	}

}

Output…

Output from Server .... 

Product created : Product [name=iPad 4, qty=100]

Download Source Code

$ git clone https://github.com/favtuts/java-jax-rs-tutorials.git
$ cd jax-rs-resteasy-client-example

References

  1. Jackson Official Website
  2. RESTful Java client with java.net.URL
  3. RESTful Java client with Apache HttpClient

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