public void connect(String server, int servPort) throws IOException,UnknownHostException, SocketTimeoutException {
       
          
        InetAddress ad = InetAddress.getByName(server);
        boolean state = ad.isReachable(1000);//测试是否可以达到该地址 ,判断ip是否可以连接 1000是超时时间
        if(state){
           System.out.println("连接成功" + ad.getHostAddress());
        } else{
           System.out.println("连接失败");
          
           throw new IOException();
        }
        //1.创建一个Socket实例：构造函数向指定的远程主机和端口建立一个TCP连接
       // socket = new Socket(server, servPort);
        socket = new Socket();
        socket.setReceiveBufferSize(8192);
        socket.setSoTimeout(1000);// socket.setSoTimeout(2000);
        SocketAddress address = new InetSocketAddress(server, servPort);
        try {
            socket.connect(address,1000);//1.判断ip、端口是否可连接
        } catch (IOException e) {
            System.out.println("新建一个 socket server "+ servPort+"连接失败");
            throw new IOException();
        } 
        System.out.println("新建一个socket");
        // System.out.println("Connected to server... sending echo string");
        //2. 通过套接字的输入输出流进行通信：一个Socket连接实例包括一个InputStream和一个OutputStream，它们的用法同于其他Java输入输出流。
        in = socket.getInputStream();
        out = socket.getOutputStream();
        isalreadyconnected=1;
        //  connect1( server,  servPort) ;
    }