src/org/nutz/lang/socket/Sockets.java
public static Socket safeClose(Socket socket) {
        if (null != socket)
            try {
                socket.close();
                socket = null;
            }
            catch (IOException e) {
                throw Lang.wrapThrow(e);
            }
        return null;
    }
public static Socket safeClose(Socket socket) {
        if (null != socket)
            try {
                socket.close();
                socket = null;
            }
            catch (IOException e) {
                throw Lang.wrapThrow(e);
            }
        return null;
    }
安全关闭套接层，容忍 null

@param socket
套接层
@return 一定会返回 null