使用Java实现UDP一对一聊天

发送者进程

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;

public class TalkSender implements Runnable{
    private DatagramSocket sender;
    private BufferedReader reader;
    private DatagramPacket packet;

    private int localPort;//本进程端口
    private String targetIP;//目标主机IP
    private int targetPort;//目标主机端口

    public TalkSender(int localPort,String targetIP,int targetPort){
        this.localPort = localPort;
        this.targetIP = targetIP;
        this.targetPort = targetPort;
        try {
            sender = new DatagramSocket(localPort);//创建发送端
            reader = new BufferedReader(new InputStreamReader(System.in));//创建文本输入器
        }catch (Exception e){
            e.printStackTrace();
        }
    }
    @Override
    public void run() {
        String msg;
        try {
            while (true) {
                msg = reader.readLine();
                byte[] datas = msg.getBytes();
                packet = new DatagramPacket(datas,0,datas.length,
                        new InetSocketAddress(this.targetIP,this.targetPort));
                sender.send(packet);
                if (msg.equals("exit")){
                    break;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        sender.close();
        try {
            if(reader!=null){
                reader.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

接收者进程

import java.net.DatagramPacket;
import java.net.DatagramSocket;

public class TalkReceiver implements Runnable {
    private DatagramSocket receiver;
    private DatagramPacket packet;
    private String targetName;

    private int localPort;//本进程端口

    public TalkReceiver(int localPort,String targetName){
        this.localPort = localPort;
        this.targetName = targetName;
    }

    @Override
    public void run() {
        try {
            receiver = new DatagramSocket(localPort);//创建接收端
            while (true) {
                byte[] buf = new byte[1024*60];
                DatagramPacket p = new DatagramPacket(buf,0,buf.length);
                receiver.receive(p);//阻塞
                String msg = new String(p.getData(),0,p.getLength());
                System.out.println(targetName+":"+msg);
                if (msg.equals("exit")){
                    break;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        receiver.close();
    }
}

主程序

public class Client {
    public static void main(String[] args) {
        new Thread(new TalkSender(4396,"localhost",2800)).start();
        new Thread(new TalkReceiver(7777,"对方")).start();
    }
}

public class Server {
    public static void main(String[] args) {
        new Thread(new TalkReceiver(2800,"对方")).start();
        new Thread(new TalkSender(6666,"localhost",7777)).start();
    }
}

为了实现客服端和服务端双向交流，需要利用多线程实现