This tutorial show you how to use Apache HttpClient to create a RESTful Java client to perform “GET” requests to REST service.
Pre-requirement:
Deploy Project RESTFul Service with Java Using JAX-RS and Jersey: https://crunchify.com/how-to-build-restful-service-with-java-using-jax-rs-and-jersey/
Once deployed, make sure your Web Server Tomcat is running and URL http://localhost:8080/CrunchifyRESTJerseyExample/crunchify/ctofservice/ is accessible.
Here are all required Maven Dependencies to run above example and all 3 Clients.
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<dependency> <groupId>com.sun.jersey</groupId> <artifactId>jersey-server</artifactId> <version>1.19</version> </dependency> <dependency> <groupId>com.sun.jersey</groupId> <artifactId>jersey-client</artifactId> <version>1.19</version> </dependency> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpcore</artifactId> <version>4.4-beta1</version> </dependency> <dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.4-beta1</version> </dependency> <dependency> <groupId>org.json</groupId> <artifactId>json</artifactId> <version>20141113</version> </dependency> |
Project Structure:
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package crunchify.com.tutorial; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import org.apache.http.HttpResponse; import org.apache.http.client.ClientProtocolException; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.HttpClientBuilder; /** * @author Crunchify.com * */ public class CrunchifyRESTJerseyApacheHTTPClient { public static void main(String[] args) { try { // create HTTP Client HttpClient httpClient = HttpClientBuilder.create().build(); // Create new getRequest with below mentioned URL HttpGet getRequest = new HttpGet("http://localhost:8080/CrunchifyRESTJerseyExample/crunchify/ctofservice/"); // Add additional header to getRequest which accepts application/xml data getRequest.addHeader("accept", "application/xml"); // Execute your request and catch response HttpResponse response = httpClient.execute(getRequest); // Check for HTTP response code: 200 = success if (response.getStatusLine().getStatusCode() != 200) { throw new RuntimeException("Failed : HTTP error code : " + response.getStatusLine().getStatusCode()); } // Get-Capture Complete application/xml body response BufferedReader br = new BufferedReader(new InputStreamReader((response.getEntity().getContent()))); String output; System.out.println("============Output:============"); // Simply iterate through XML response and show on console. while ((output = br.readLine()) != null) { System.out.println(output); } } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } } |
Output:
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============Output:============ <ctofservice><celsius>36.8</celsius><ctofoutput>@Produces("application/xml") Output: C to F Converter Output: 98.24</ctofoutput></ctofservice> |
Other must read:
how I can put parameters for send to other PC in the Rest client?
Hi Walinka – could you please send your requirement in details?
Tutorial is very helpful. Thanks!
Thanks Riki. Happy coding and keep visiting.
Hi, I was trying to use your code, but was having errors with the jar files, if you don’t mind, could you please tell me which .jar files were used in the example!
Thank you
Hi Ameera – You need below 5 .jar files:
Thank you for this example. I imported all the jar files specified, literally pasted all the Java code in your example (with the exception of a different URL). Only error i’m getting with is the row “HttpResponse response = httpClient.execute(getRequest);”. Error says “getRequest cannot be resolved to a variable”. Any idea’s for other things I could try?
DefaultHttpClient is deprecated
Thanks Ganesh for hint. I’ll update tutorial with
HttpClientin couple of days.Just updated above tutorial with correct HttpClient.
Thank you 🙂
Hello App Shah, thanks for the tutorial. I am very new to java. In this example I can only run from the console. what changed will be required to get the response on the browser. Thanks again
Hi Liri – no change required. You could use the same URL in browser: http://localhost:8080/CrunchifyRESTJerseyExample/crunchify/ctofservice/
Hi Kale. Sorry for late reply. It’s been super busy at my end. Will try to create one simple example based on above requirement.
Hi Aprit, thank you for the simple yet self explanatory examples. My requirement is to create a RestFul WS client to run on Apache HTTP server that is expected to
1. Get authenticated via JKS
2. Listen on the delivery URL of the publisher
3. respond to HTTP PUT and DELETE methods
The examples you provided make requests rather than listening on a publisher URL. Do you have any examples covering the above points?
Thanks in advance.
Excellent tutorial!!!! Thanks a lot:)
I’m glad you like it Mariselvam..