网络编程-写一个聊天程序

这个可以在局域网内、沟通
package mymenu;

import java.net.*;
import java.util.*;
public class PracticeUsed  {

    public static void main(String[] args) throws Exception   {
        
        DatagramSocket ds = new DatagramSocket();
        DatagramSocket dd = new DatagramSocket(10002);
        
        new Thread(new MySend(ds)).start();
        new Thread(new MyRece(dd)).start();
    }
}


class MySend implements Runnable
{
    private DatagramSocket ds;
    public MySend(DatagramSocket ds)
    {
        this.ds = ds;
    }
    
    public void run()
    {
        try
        {
            while(true)
            {
                Scanner in = new Scanner(System.in);
                String text = in.nextLine();
                
                
                byte[] buf = text.getBytes();
                DatagramPacket dp = new DatagramPacket(buf,buf.length,InetAddress.getByName("199.234.8.53"),10002);
                
                // 注意： 每个号段当中最后的.255 、代表是局域网的广播频道
                ds.send(dp);
            }
        }
        catch(Exception e )
        {
            throw new RuntimeException("发送端挂了");
        }
    }
}

class MyRece implements Runnable
{
    private DatagramSocket ds;
    public MyRece(DatagramSocket ds)
    {
        this.ds = ds;
    }
    public void run()
    {
        try
        {
            while(true)
            {
                byte[] buf = new byte[1024];
                DatagramPacket dp = new DatagramPacket(buf,buf.length);
                ds.receive(dp);
                String ip = dp.getAddress().getHostAddress();
                
                String data = new String(dp.getData(),0,dp.getLength());
                
                System.out.println(ip+"::"+data);
                System.out.println("");
            
            }
        }
        catch(Exception e )
        {
            throw new RuntimeException("接收端挂了");
        }
    }
}