UDP协议

public class Client {
    public static void main(String[] args) throws IOException {
        
        InetAddress address = InetAddress.getByName("localhost");
        int port = 8800;
        byte[] data = "用户名admin；密码123".getBytes();
        DatagramPacket packet = new DatagramPacket(data, data.length,address,port);
        DatagramSocket socket = new DatagramSocket();
        socket.send(packet);
        
        byte[] data2 = new byte[1024];
        DatagramPacket packet2 = new DatagramPacket(data2, data2.length);
        socket.receive(packet2);
        String reply = new String(data2,0,packet2.getLength());
        System.out.println(reply);
        socket.close();
    }
}

public class Server {
    public static void main(String[] args) throws IOException {
        DatagramSocket socket = new DatagramSocket(8800);
        byte[] data = new byte[1024];
        DatagramPacket packet = new DatagramPacket(data, data.length);
        socket.receive(packet);
        String info = new String(data,0,packet.getLength());
        System.out.println("我是服务器，客户端说:" + info);
        
        InetAddress address = packet.getAddress() ;
        int port = packet.getPort();
        byte[] data2 = "欢迎您".getBytes();
        DatagramPacket packet2 =new DatagramPacket(data2, data2.length,address,port);
        socket.send(packet2);
        socket.close();
    }
}