SOCKET_UDP包的发送及接收

package com.kk.review;

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

public class UDPServer {
    
    public static void main(String[] args) {
        UDPServer.receive();
    }
    
    static void receive(){
        try{
            DatagramSocket ds=new DatagramSocket(8890);
            byte[] buf=new byte[100];
            DatagramPacket dp=new DatagramPacket(buf,100);
            ds.receive(dp);
            String str=new String(buf,0,dp.getLength());
            System.out.println("from client:"+str);
            String str1="welcome you!";
            DatagramPacket dp1=new DatagramPacket(str1.getBytes(),str1.length(),dp.getAddress(),dp.getPort());
            ds.send(dp1);
            ds.close();
        }catch(IOException e){
            e.printStackTrace();
        }
    }
}

package com.kk.review;

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

public class UDPClient {
    public static void main(String[] args) {
        UDPClient.send();
    }
    static void send() {
        try{
            DatagramSocket ds=new DatagramSocket();
            String str="hello udp";
            DatagramPacket dp=new DatagramPacket(str.getBytes(),str.length(),InetAddress.getLocalHost(),8890);
            ds.send(dp);
            byte[] buf=new byte[100];
            DatagramPacket dp1=new DatagramPacket(buf,100);
            ds.receive(dp1);
            String str1=new String(buf,0,dp1.getLength());
            System.out.println(str1);
　　　　　　　ds.close();
        }catch(IOException e){
            e.printStackTrace();
        }
        
    }
}