而且這兩個方法要封裝到不同的類中。

import java.io.*;
import java.net.*;
class Send implements Runnable
{
	private DatagramSocket ds;
	public Send(DatagramSocket ds)
	{
		this.ds = ds;
	}
	public void run()
	{
		try
		{
			BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));

			String line = null;

			while((line=bufr.readLine())!=null)
			{	

				byte[] buf = line.getBytes();

				DatagramPacket dp =new DatagramPacket(buf,buf.length,InetAddress.getByName("192.168.1.255"),10002);

				ds.send(dp);

				if("886".equals(line))
					break;
			}
		}
		catch (Exception e)
		{
			throw new RuntimeException("傳送端失敗");
		}
	}
}

class Rece implements Runnable
{
	private DatagramSocket ds;
	public Rece(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());
				if("886".equals(data))
				{
					System.out.println(ip+"....離開聊天室");
					break;
				}
				System.out.println(ip+":"+data);
			}
		}
		catch (Exception e)
		{
			throw new RuntimeException("接收端失敗");
		}
	}
}


class  ChatDemo
{
	public static void main(String[] args) throws Exception
	{
		DatagramSocket sendSocket = new DatagramSocket();
		DatagramSocket receSocket = new DatagramSocket(10002);

		new Thread(new Send(sendSocket)).start();
		new Thread(new Rece(receSocket)).start();
	}
}
 

——摘自《畢向東25天》