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## org.apache.http.client
Interface HttpClient

All Known Implementing Classes:
  AbstractHttpClient, AutoRetryHttpClient, CachingHttpClient, ContentEncodingHttpClient, DecompressingHttpClient, DefaultHttpClient, SystemDefaultHttpClient

    public interface HttpClient

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();
     }

Since:
  4.0

Method Summary
`HttpResponse` | `execute(HttpHost target, HttpRequest request)` Executes a request to the target using the default context.
`HttpResponse` | `execute(HttpHost target, HttpRequest request, HttpContext context)` Executes a request to the target using the given context.
`
`<T> T`
` | `execute(HttpHost target, HttpRequest request, ResponseHandler<? extends T> responseHandler)` Executes a request to the target using the default context and processes the response using the given response handler.
`
`<T> T`
` | `execute(HttpHost target, HttpRequest request, ResponseHandler<? extends T> responseHandler, HttpContext context)` Executes a request to the target using the given context and processes the response using the given response handler.
`HttpResponse` | `execute(HttpUriRequest request)` Executes a request using the default context.
`HttpResponse` | `execute(HttpUriRequest request, HttpContext context)` Executes a request using the given context.
`
`<T> T`
` | `execute(HttpUriRequest request, ResponseHandler<? extends T> responseHandler)` Executes a request using the default context and processes the response using the given response handler.
`
`<T> T`
` | `execute(HttpUriRequest request, ResponseHandler<? extends T> responseHandler, HttpContext context)` Executes a request using the given context and processes the response using the given response handler.
`ClientConnectionManager` | `getConnectionManager()` Obtains the connection manager used by this client.
`HttpParams` | `getParams()` Obtains the parameters for this client.

Method Detail

### getParams

    HttpParams getParams()

  Obtains the parameters for this client. These parameters will become defaults for all requests being executed with this client, and for the parameters of dependent objects in this client.

  Returns:
    the default parameters

### getConnectionManager

    ClientConnectionManager getConnectionManager()

  Obtains the connection manager used by this client.

  Returns:
    the connection manager

### execute

    HttpResponse execute(HttpUriRequest request)
                         throws IOException,
                                ClientProtocolException

  Executes a request using the default context.

  Parameters:
    `request` - the request to execute
  Returns:
    the response to the request. This is always a final response, never an intermediate response with an 1xx status code. Whether redirects or authentication challenges will be returned or handled automatically depends on the implementation and configuration of this client.
  Throws:
    `IOException` - in case of a problem or the connection was aborted
    `ClientProtocolException` - in case of an http protocol error

### execute

    HttpResponse execute(HttpUriRequest request,
                         HttpContext context)
                         throws IOException,
                                ClientProtocolException

  Executes a request using the given context. The route to the target will be determined by the HTTP client.

  Parameters:
    `request` - the request to execute
    `context` - the context to use for the execution, or `null` to use the default context
  Returns:
    the response to the request. This is always a final response, never an intermediate response with an 1xx status code. Whether redirects or authentication challenges will be returned or handled automatically depends on the implementation and configuration of this client.
  Throws:
    `IOException` - in case of a problem or the connection was aborted
    `ClientProtocolException` - in case of an http protocol error

### execute

    HttpResponse execute(HttpHost target,
                         HttpRequest request)
                         throws IOException,
                                ClientProtocolException

  Executes a request to the target using the default context.

  Parameters:
    `target` - the target host for the request. Implementations may accept `null` if they can still determine a route, for example to a default target or by inspecting the request.
    `request` - the request to execute
  Returns:
    the response to the request. This is always a final response, never an intermediate response with an 1xx status code. Whether redirects or authentication challenges will be returned or handled automatically depends on the implementation and configuration of this client.
  Throws:
    `IOException` - in case of a problem or the connection was aborted
    `ClientProtocolException` - in case of an http protocol error

### execute

    HttpResponse execute(HttpHost target,
                         HttpRequest request,
                         HttpContext context)
                         throws IOException,
                                ClientProtocolException

  Executes a request to the target using the given context.

  Parameters:
    `target` - the target host for the request. Implementations may accept `null` if they can still determine a route, for example to a default target or by inspecting the request.
    `request` - the request to execute
    `context` - the context to use for the execution, or `null` to use the default context
  Returns:
    the response to the request. This is always a final response, never an intermediate response with an 1xx status code. Whether redirects or authentication challenges will be returned or handled automatically depends on the implementation and configuration of this client.
  Throws:
    `IOException` - in case of a problem or the connection was aborted
    `ClientProtocolException` - in case of an http protocol error

### execute

    <T> T execute(HttpUriRequest request,
                  ResponseHandler<? extends T> responseHandler)
              throws IOException,
                     ClientProtocolException

  Executes a request using the default context and processes the response using the given response handler.

  Implementing classes are required to ensure that the content entity associated with the response is fully consumed and the underlying connection is released back to the connection manager automatically in all cases relieving individual `ResponseHandler` from having to manage resource deallocation internally.

  Parameters:
    `request` - the request to execute
    `responseHandler` - the response handler
  Returns:
    the response object as generated by the response handler.
  Throws:
    `IOException` - in case of a problem or the connection was aborted
    `ClientProtocolException` - in case of an http protocol error

### execute

    <T> T execute(HttpUriRequest request,
                  ResponseHandler<? extends T> responseHandler,
                  HttpContext context)
              throws IOException,
                     ClientProtocolException

  Executes a request using the given context and processes the response using the given response handler.

  Implementing classes are required to ensure that the content entity associated with the response is fully consumed and the underlying connection is released back to the connection manager automatically in all cases relieving individual `ResponseHandler` from having to manage resource deallocation internally.

  Parameters:
    `request` - the request to execute
    `responseHandler` - the response handler
    `context` - the context to use for the execution, or `null` to use the default context
  Returns:
    the response object as generated by the response handler.
  Throws:
    `IOException` - in case of a problem or the connection was aborted
    `ClientProtocolException` - in case of an http protocol error

### execute

    <T> T execute(HttpHost target,
                  HttpRequest request,
                  ResponseHandler<? extends T> responseHandler)
              throws IOException,
                     ClientProtocolException

  Executes a request to the target using the default context and processes the response using the given response handler.

  Implementing classes are required to ensure that the content entity associated with the response is fully consumed and the underlying connection is released back to the connection manager automatically in all cases relieving individual `ResponseHandler` from having to manage resource deallocation internally.

  Parameters:
    `target` - the target host for the request. Implementations may accept `null` if they can still determine a route, for example to a default target or by inspecting the request.
    `request` - the request to execute
    `responseHandler` - the response handler
  Returns:
    the response object as generated by the response handler.
  Throws:
    `IOException` - in case of a problem or the connection was aborted
    `ClientProtocolException` - in case of an http protocol error

### execute

    <T> T execute(HttpHost target,
                  HttpRequest request,
                  ResponseHandler<? extends T> responseHandler,
                  HttpContext context)
              throws IOException,
                     ClientProtocolException

  Executes a request to the target using the given context and processes the response using the given response handler.

  Implementing classes are required to ensure that the content entity associated with the response is fully consumed and the underlying connection is released back to the connection manager automatically in all cases relieving individual `ResponseHandler` from having to manage resource deallocation internally.

  Parameters:
    `target` - the target host for the request. Implementations may accept `null` if they can still determine a route, for example to a default target or by inspecting the request.
    `request` - the request to execute
    `responseHandler` - the response handler
    `context` - the context to use for the execution, or `null` to use the default context
  Returns:
    the response object as generated by the response handler.
  Throws:
    `IOException` - in case of a problem or the connection was aborted
    `ClientProtocolException` - in case of an http protocol error

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