使用apache.DefaultHttpClient的Http连接进入TIME_WAIT，不会被重用

Question

我们有一个HttpClient(apache.DefaultHttpClient)对象池(GenericObjectPool)。通过这些客户端将HttpPost对象放入执行，可以同时发送Post请求。使用的协议是: HTTP/1.1 with keepalive。

在通过netstat进行负载测试期间观察到，新的套接字连接被不加区别地创建，而旧的连接转到TIME_WAIT。

日志摘录：

[Worker-2] org.apache.http.impl.conn.Wire 63 - >> "POST /INBOX/4504a09e-13c0-3853-a285-9e2b9a22f65e/1e1e5a20-a8c1-11e2-99b8-7c19e9129271 HTTP/1.1[\r][\n]"

[Worker-2] org.apache.http.impl.conn.Wire 63 - >> "Content-Type: application/json; charset=UTF-8[\r][\n]"

[Worker-2] org.apache.http.impl.conn.Wire 63 - >> "Content-Length: 117[\r][\n]"

[Worker-2] org.apache.http.impl.conn.Wire 63 - >> "Host: rwcdtgxb0402:15010[\r][\n]"

[Worker-2] org.apache.http.impl.conn.Wire 63 - >> "Connection: Keep-Alive[\r][\n]"

[Worker-2] org.apache.http.impl.conn.Wire 63 - >> "User-Agent: Apache-HttpClient/4.2.1 (java 1.5)[\r][\n]"

[Worker-2] org.apache.http.impl.conn.Wire 63 - >> "[\r][\n]"

[Worker-2] org.apache.http.impl.conn.Wire 63 - << "HTTP/1.1 200 OK[\r][\n]"

[Worker-2] org.apache.http.impl.conn.Wire 63 - << "Content-Length: 0[\r][\n]"

[Worker-2] org.apache.http.impl.conn.Wire 63 - << "[\r][\n]"

[Worker-2] org.apache.http.impl.conn.DefaultClientConnection 254 - Receiving response: HTTP/1.1 200 OK

[Worker-2] org.apache.http.impl.conn.DefaultClientConnection 257 - << HTTP/1.1 200 OK

[Worker-2] org.apache.http.impl.conn.DefaultClientConnection 260 - << Content-Length: 0

[Worker-2] org.apache.http.impl.client.DefaultRequestDirector 540 - Connection can be kept alive indefinitely

**[Worker-2] org.apache.http.impl.conn.DefaultClientConnection 154 - Connection 0.0.0.0:51211<->192.168.88.172:15010 shut down**

[Worker-2] org.apache.http.impl.conn.BasicClientConnectionManager 189 - Releasing connection org.apache.http.impl.conn.ManagedClientConnectionImpl@12f65ce5

DefaultClientConnection.shutdown (Connection 0.0.0.0:51210<->192.168.88.172:15010关闭)是否关闭了客户端的连接？它是如何被调用的？在代码中，从服务器收到响应(200OK)后，httpPost.releaseConnection()只在客户端代码中执行。

我应该怎么做才能保持连接处于已建立状态并重用它们，而不是为每个请求创建连接，然后它们进入TIME_WAIT。

任何帮助都将受到高度的感谢。谢谢。

Answer 1

注意:调用EntityUtils.console(entity)会做更多的事情，应该使用：

    /**
     * Ensures that the entity content is fully consumed and 
     * the content stream, if exists, is closed.
     *
     * @param entity the entity to consume.
     * @throws IOException if an error occurs reading the input stream
     *
     * @since 4.1
     */
    public static void consume(final HttpEntity entity) throws IOException {
        if (entity == null) {
            return;
        }
        if (entity.isStreaming()) {
            final InputStream inStream = entity.getContent();
            if (inStream != null) {
                inStream.close();
            }
        }
    }

Answer 2

几天前解决了这个问题。

错误:在HttpClient对象上调用releaseConnection()。但是，避免它也不能解决问题。

更正:为保持连接活动(处于ESTABLISHED状态)而采取的操作是通过以下示例代码：

HttpClient client = new org.apache.http.impl.client.DefaultHttpClient();
...
org.apache.http.HttpResponse response = client.executed(HttpPost) ;
org.apache.http.HttpEntity en = response.getEntity();
if (en != null) {
  en.getContent().close();
}

一旦接收到HttpResponse，为了重用和维护所创建的连接，只需要关闭http-response上的InputStream (en.getContent())。请勿对HttpPost或客户端对象调用任何其他release方法。

用JMeter load测试了这个处理，发现它工作正常。还没有观察到任何副作用！