JAVA UDP客户端服务端编写实例,   byte[] buffer=new byte[256]; //缓冲区数组   DatagramSocket socket=new DatagramSocket(port);//实例化数据报Socket   DatagramPacket packet;   System.out.println("Server start..."); //输出运行信息   while (true){   packet=new DatagramPacket(buffer,buffer.length); //实例化数据报   socket.receive(p