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.
<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:
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:
============Output:============
<ctofservice><celsius>36.8</celsius><ctofoutput>@Produces("application/xml") Output:
C to F Converter Output:
98.24</ctofoutput></ctofservice>
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