Apache HttpComponents HttpClient timeout

问题:

How do I set the connection timeout in httpcomponents httpclient? I have found the documentation at: http://hc.apache.org/httpcomponents-client-ga/tutorial/html/connmgmt.html but it is not clear how these parameters are actually set.

Also, an explanation of the difference between SO_TIMEOUT and CONNECTION_TIMEOUT would be helpful.

回答1:

In version 4.3 of Apache Http Client the configuration was refactored (again). The new way looks like this:

RequestConfig.Builder requestBuilder = RequestConfig.custom();
requestBuilder = requestBuilder.setConnectTimeout(timeout);
requestBuilder = requestBuilder.setConnectionRequestTimeout(timeout);

HttpClientBuilder builder = HttpClientBuilder.create();     
builder.setDefaultRequestConfig(requestBuilder.build());
HttpClient client = builder.build();

回答2:

The answer from @jontro is correct, but it's always nice to have a code snippet on how to do this. There are two ways to do this:

Version 1: Set a 10 second timeout for each of these parameters:

HttpClient httpclient = new DefaultHttpClient();
// this one causes a timeout if a connection is established but there is 
// no response within 10 seconds
httpclient.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT, 10 * 1000);

// this one causes a timeout if no connection is established within 10 seconds
httpclient.getParams().setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, 10 * 1000);

// now do the execute:
HttpGet httpget = new HttpGet(URL);
HttpResponse response = httpclient.execute(httpget);

Version 2: Also set a 10 second timeout for each of these parameters:

HttpParams params = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(params, 10 * 1000);
HttpConnectionParams.setSoTimeout(params, 10 * 1000);

HttpClient httpclient = new DefaultHttpClient(params);
HttpGet httpget = new HttpGet(URL);
HttpResponse response = httpclient.execute(httpget);

回答3:

In HttpClient 4.3 version you can use below example.. let say for 5 seconds

int timeout = 5;
RequestConfig config = RequestConfig.custom()
  .setConnectTimeout(timeout * 1000)
  .setConnectionRequestTimeout(timeout * 1000)
  .setSocketTimeout(timeout * 1000).build();
CloseableHttpClient client = 
  HttpClientBuilder.create().setDefaultRequestConfig(config).build();
HttpGet request = new HttpGet("http://localhost:8080/service"); // GET Request
response = client.execute(request);

回答4:

In section 2.5 you see an example of how to set the CONNECTION_TIMEOUT parameter.

CONNECTION_TIMEOUT is the time waiting for the initial connection and SO_TIMEOUT is the timeout that you wait for when reading a packet after the connection is established.

回答5:

I set a hard timeout for the entire request to workaround the java.net.SocketInputStream.socketRead0 problem.

private static final ScheduledExecutorService SCHEDULED_EXECUTOR = Executors.newSingleThreadScheduledExecutor()

HttpGet request = new HttpGet("http://www.example.com")
final Runnable delayedTask = new Runnable() {
    @Override
    public void run() {
        request.abort()
    }
}
SCHEDULED_EXECUTOR.schedule(delayedTask, 100000, TimeUnit.MILLISECONDS)