JAVA的UDP协议交互信息

package com.test1;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketException;

public class UpdServer {
    private byte[] buff = new byte[1024];
    private DatagramPacket dp;
    private DatagramSocket ds;
    private InetSocketAddress socketAddress;
    public UpdServer(String host, int port){
        socketAddress = new InetSocketAddress(host, port);
        try {
            ds = new DatagramSocket(socketAddress);
        } catch (SocketException e) {
            System.out.println("连接失败:" + e.getLocalizedMessage());
            e.printStackTrace();
        }
        System.out.println("服务器开启监听...");
    }
    
    private String receive(String host, int port) {
        String info = "";
        try{
            dp = new DatagramPacket(buff, 0, buff.length);
            ds.receive(dp);
            info = new String(dp.getData(), 0, dp.getLength());
        }catch (Exception e) {
            e.printStackTrace();
        }
        return info;
    }
    
    public static void main(String[] args) {
        String host = "127.0.0.1";
        int port = 8888;
        UpdServer server = new UpdServer(host, port);
        String info = server.receive(host, port);
        System.out.println(info);
        //发送信息到客服端
        server.send(new String("你好，骚年！"));
    }

    private void send(String string) {
        DatagramPacket dps = new DatagramPacket(buff, 0, buff.length, dp.getAddress(), dp.getPort());
        dps.setData(string.getBytes());
        try {
            ds.send(dps);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

package com.test1;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;

public class UpdClient {
    private byte[] buff = new byte[1024];
    private DatagramPacket dp;
    private DatagramSocket ds;
    public UpdClient(){
        try {
            ds = new DatagramSocket();
        } catch (SocketException e) {
            e.printStackTrace();
        }
    }
    
    public static void main(String[] args) {
        UpdClient updClient = new UpdClient();
        String host = "127.0.0.1";
        int port = 8888;
        updClient.send(host, port, new String("你好，少年!").getBytes());
        
        //接受
        String info = updClient.receive();
        System.out.println(info);
    }

    private String receive() {
        DatagramPacket dpr = new DatagramPacket(buff, buff.length);
        String info = "";
        try {
            ds.receive(dpr);
            info = new String(dpr.getData(), 0, dpr.getLength());
        } catch (IOException e) {
            e.printStackTrace();
        }
        return info;
    }

    private void send(String host, int port, byte[] b) {
        try{
            dp = new DatagramPacket(buff, 0, buff.length, InetAddress.getByName(host), port);
            dp.setData(b);
            ds.send(dp);
        }catch (Exception e) {
            e.printStackTrace();
        }
    }
}