Java设置Client Socket链接Server超时时间

一、错误示例

最近在写socket程序时，偶然发现程序被卡住很长时间，调试后发现是创建Socket时，采用的方式不对：

Socket s = new Socket(String host, String port);

当采用该方式创建

Socket

时，默认的链接超时时间为0（A timeout of zero is interpreted as an infinite timeout. The connection will then block until established or an error occurs.），也就意味着链接永不超时，直到发生链接超时异常，所以程序会被卡住，并最终抛出异常。

二、正确示例

若要设置链接超时，需要使用如下方式创建

Socket

：

Socket s = new Socket();
SocketAddress socketAddress = new InetSocketAddress(serverIp, port);
s.connect(socketAddress, timeout);

其中

timeout

就是设置的超时时间，当超时时间到时会抛出

SocketTimeoutException

而不会无限等待的去尝试链接。

附

设置从Socket读取数据超时

通过

Socket

方法

setSoTimeout(int timeout)

，Javadoc关于该方法的的说明如下：

Enable/disable SO_TIMEOUT with the specified timeout, in milliseconds.

With this option set to a non-zero timeout, a read() call on the InputStream associated with this Socket will block for only this amount of time.

If the timeout expires, a java.net.SocketTimeoutException is raised, though the Socket is still valid.

The option must be enabled prior to entering the blocking operation to have effect.

The timeout must be > 0. A timeout of zero is interpreted as an infinite timeout.