RESTful Java client by using java.net.URL

Here we will use “java.net.URL” and “java.net.HttpURLConnection” to create a simple Java client to send “GET” and “POST” request.

GET Request

REST service that return “json” data back to client.

	@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;
	}
	//...

view raw JSONService.java hosted with ❤ by GitHub

Java client to send a “GET” request:

	import java.io.BufferedReader;
	import java.io.IOException;
	import java.io.InputStreamReader;
	import java.net.HttpURLConnection;
	import java.net.MalformedURLException;
	import java.net.URL;
	public class NetClientGet {
	// http://localhost:8080/RESTfulExample/json/product/get
	public static void main(String[] args) {
	try {
	URL url = new URL("http://localhost:8080/RESTfulExample/json/product/get");
	HttpURLConnection conn = (HttpURLConnection)url.openConnection();
	conn.setRequestMethod("GET");
	conn.setRequestProperty("Accept", "application/json");
	if (conn.getResponseCode() != 200) {
	throw new RuntimeException("Failed : HTTP error code : "
	+ conn.getResponseCode());
	}
	BufferedReader br = new BufferedReader(new InputStreamReader(
	(conn.getInputStream())));
	String output;
	System.out.println("Output from Server .... \n");
	while ((output = br.readLine()) != null) {
	System.out.println(output);
	}
	conn.disconnect();
	}
	catch (MalformedURLException e) {
	e.printStackTrace();
	}
	catch (IOException e) {
	e.printStackTrace();
	}
	}
	}

view raw NetClientGet.java hosted with ❤ by GitHub

Output:

Output from Server .... 
{"qty":999,"name":"iPad 3"}

NOTE: Same way, by using "POST" method  we can create Java Client using java.net.URL with few changes in the above code.

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