httclient caught when connecting to the target host:Address already in use 悟寰轩

转自：http://seanhe.iteye.com/blog/234759

方法一： 
把事例代码中的第一行实例化代码改为如下即可，在method.releaseConnection();之后connection manager会关闭connection 。 

HttpClient client = new HttpClient(new HttpClientParams(),new SimpleHttpConnectionManager(true) );

方法二： 
实例化代码使用：HttpClient client = new HttpClient(); 
在method.releaseConnection();之后加上 

((SimpleHttpConnectionManager)client.getHttpConnectionManager()).shutdown();

shutdown源代码很简单，看了一目了然 

public void shutdown() {
    httpConnection.close();
}

方法三： 
实例化代码使用：HttpClient client = new HttpClient(); 
在method.releaseConnection();之后加上 
client.getHttpConnectionManager().closeIdleConnections(0);此方法源码代码如下： 

public void closeIdleConnections(long idleTimeout) {
    long maxIdleTime = System.currentTimeMillis() - idleTimeout;
    if (idleStartTime <= maxIdleTime) {
        httpConnection.close();
    }
}

将idleTimeout设为0可以确保链接被关闭。 
以上这三种方法都是有客户端主动关闭TCP链接的方法。下面再介绍由服务器端自动关闭链接的方法。 
方法四： 
代码实现很简单，所有代码就和最上面的事例代码一样。只需要在HttpMethod method = new GetMethod("http://www.apache.org");加上一行HTTP头的设置即可 

method.setRequestHeader("Connection", "close");

看一下HTTP协议中关于这个属性的定义： 
HTTP/1.1 defines the "close" connection option for the sender to signal that the connection will be closed after completion of the response. For example, 
       Connection: close