java 校验ftp 是否可连通

 /**
     * 用于检测FTP是否能够连接上，如果连接不上直接抛出异常
     *
     * @param ip
     * @param port
     * @throws IOException
     * @see [类、类#方法、类#成员]
     */
    private void checkFtpConnection()
        throws IOException
    {
        // 入口日志
        log.getRun().info(StatIDConstants.ENTER_METHOD,
            Logger.newAttrs(StatIDConstants.METHOD_NAME, "checkFtpConnection()"));

        Socket socket = null;
        try
        {
            socket = new Socket();
            socket.connect(new InetSocketAddress(hostname, port), FTP_ISCONN_TIMEOUT);
        }
        finally
        {
            if (null != socket)
            {
                socket.close();
            }
        }
        // 出口日志
        log.getRun().info(StatIDConstants.EXIT_METHOD,
            Logger.newAttrs(StatIDConstants.METHOD_NAME, "checkFtpConnection()"));
    }