HttpClient

Class Overview

This interface represents only the most basic contract for HTTP request execution. It imposes no restrictions or particular details on the request execution process and leaves the specifics of state management, authentication and redirect handling up to individual implementations. This should make it easier to decorate the interface with additional functionality such as response content caching.

The usual execution flow can be demonstrated by the code snippet below:

 HttpClient httpclient = new DefaultHttpClient();

 // Prepare a request object
 HttpGet httpget = new HttpGet("http://www.apache.org/");

 // Execute the request
 HttpResponse response = httpclient.execute(httpget);

 // Examine the response status
 System.out.println(response.getStatusLine());

 // Get hold of the response entity
 HttpEntity entity = response.getEntity();

 // If the response does not enclose an entity, there is no need
 // to worry about connection release
 if (entity != null) {
     InputStream instream = entity.getContent();
     try {

         BufferedReader reader = new BufferedReader(
                 new InputStreamReader(instream));
         // do something useful with the response
         System.out.println(reader.readLine());

     } catch (IOException ex) {

         // In case of an IOException the connection will be released
         // back to the connection manager automatically
         throw ex;

     } catch (RuntimeException ex) {

         // In case of an unexpected exception you may want to abort
         // the HTTP request in order to shut down the underlying
         // connection and release it back to the connection manager.
         httpget.abort();
         throw ex;

     } finally {

         // Closing the input stream will trigger connection release
         instream.close();

     }

     // When HttpClient instance is no longer needed,
     // shut down the connection manager to ensure
     // immediate deallocation of all system resources
     httpclient.getConnectionManager().shutdown();
 }
 

Summary