Apache HttpClient

1. Download 'Binary' package of the latest official release from the project download page.

   There should be 7 jars in total (components marked with (*) include additional features and are optional) on the classpath.

   • commons-logging-x.x.x.jar
   • commons-codec-x.x.x.jar
   • httpcore-x.x.x.jar
   • httpclient-x.x.x.jar
   • httpmime-x.x.x.jar (*)
   • httpclient-cache-x.x.x.jar (*)
   • fluent-hc-x.x.x.jar (*)
2. The below code fragment illustrates the execution of HTTP GET and POST requests using the HttpClient native API.

   CloseableHttpClient httpclient = HttpClients.createDefault();HttpGet httpGet = new HttpGet("http://targethost/homepage");CloseableHttpResponse response1 = httpclient.execute(httpGet);// The underlying HTTP connection is still held by the response object// to allow the response content to be streamed directly from the network socket.// In order to ensure correct deallocation of system resources// the user MUST either fully consume the response content  or abort request// execution by calling CloseableHttpResponse#close().try {    System.out.println(response1.getStatusLine());    HttpEntity entity1 = response1.getEntity();    // do something useful with the response body    // and ensure it is fully consumed    EntityUtils.consume(entity1);} finally {    response1.close();}HttpPost httpPost = new HttpPost("http://targethost/login");List <NameValuePair> nvps = new ArrayList <NameValuePair>();nvps.add(new BasicNameValuePair("username", "vip"));nvps.add(new BasicNameValuePair("password", "secret"));httpPost.setEntity(new UrlEncodedFormEntity(nvps));CloseableHttpResponse response2 = httpclient.execute(httpPost);try {    System.out.println(response2.getStatusLine());    HttpEntity entity2 = response2.getEntity();    // do something useful with the response body    // and ensure it is fully consumed    EntityUtils.consume(entity2);} finally {    response2.close();}

   Source can be downloaded here

3. The same requests can be executed using a simpler, albeit less flexible, fluent API.

   // The fluent API relieves the user from having to deal with manual deallocation of system// resources at the cost of having to buffer response content in memory in some cases.Request.Get("http://targethost/homepage")    .execute().returnContent();Request.Post("http://targethost/login")    .bodyForm(Form.form().add("username",  "vip").add("password",  "secret").build())    .execute().returnContent();