在多线程环境中使用HttpClient的最佳实践 [英] Best Practice to Use HttpClient in Multithreaded Environment

问题描述

有一段时间，我一直在多线程环境中使用HttpClient。对于每个线程，当它启动连接时，它将创建一个全新的HttpClient实例。

For a while, I have been using HttpClient in a multithreaded environment. For every thread, when it initiates a connection, it will create a completely new HttpClient instance.

最近，我发现，通过使用这种方法，它可以导致用户打开太多端口，大多数连接处于TIME_WAIT状态。

Recently, I have discovered that, by using this approach, it can cause the user to have too many ports being opened, and most of the connections are in TIME_WAIT state.

http://www.opensubscriber.com/message/[e-mail]/86045.html

因此，而不是每个线程在做：

Hence, instead of each thread doing :

HttpClient c = new HttpClient();
try {
    c.executeMethod(method);
}
catch(...) {
}
finally {
    method.releaseConnection();
}

我们计划：

[方法A]

// global_c is initialized once through
// HttpClient global_c = new HttpClient(new MultiThreadedHttpConnectionManager());

try {
    global_c.executeMethod(method);
}
catch(...) {
}
finally {
    method.releaseConnection();
}

在正常情况下，global_c将同时由50个++线程访问。我想知道，这会产生任何性能问题吗？ MultiThreadedHttpConnectionManager是否使用无锁机制来实现其线程安全策略？

In a normal situation, global_c will be accessed by 50++ threads concurrently. I was wondering, will this create any performance issues? Is MultiThreadedHttpConnectionManager using a lock-free mechanism to implement its thread safe policy?

如果10个线程正在使用global_c，其他40个线程是否会被锁定？

If 10 threads are using global_c, will the other 40 threads be locked?

或者它会更好如果，在每个线程中，我创建一个HttpClient的实例，但显式释放连接管理器？

Or would it be better if, in every thread, I create an instance of an HttpClient, but release the connection manager explicitly?

[方法B]

MultiThreadedHttpConnectionManager connman = new MultiThreadedHttpConnectionManager();
HttpClient c = new HttpClient(connman);
try {
      c.executeMethod(method);
}
catch(...) {
}
finally {
    method.releaseConnection();
    connman.shutdown();
}

connman.shutdown（）是否会遇到性能问题？

Will connman.shutdown() suffer performance issues?

对于使用50 ++线程的应用程序，我可以知道哪种方法（A或B）更好吗？

May I know which method (A or B) is better, for application using an 50++ threads?

推荐答案

httpclient开发者社区推荐方法A.

Method A is recommended by httpclient developer community.

请参考 http://www.mail-archive.com/[e-mail]/msg02455.html 了解更多详情。

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