使用 UDP（資料包）的基本 ClientServer 通訊

Client.java

import java.io.*;
import java.net.*;
    
public class Client{
    public static void main(String [] args) throws IOException{
        DatagramSocket clientSocket = new DatagramSocket(); 
        InetAddress address = InetAddress.getByName(args[0]);

        String ex = "Hello, World!";
        byte[] buf = ex.getBytes();

        DatagramPacket packet = new DatagramPacket(buf,buf.length, address, 4160); 
        clientSocket.send(packet);
    }
}

在這種情況下，我們通過引數（args[0]）傳入伺服器的地址。我們使用的埠是 4160。

Server.java

import java.io.*;
import java.net.*;

public class Server{
    public static void main(String [] args) throws IOException{
        DatagramSocket serverSocket = new DatagramSocket(4160);

        byte[] rbuf = new byte[256];
        DatagramPacket packet = new DatagramPacket(rbuf, rbuf.length);        
        serverSocket.receive(packet);
        String response = new String(packet.getData());
        System.out.println("Response: " + response);
    }
}

在伺服器端，在我們將訊息傳送到（4160）的同一埠上宣告 DatagramSocket 並等待響應。