java:用UDP协议，开发一个聊天工具代码

/**
	用UDP协议，开发一个聊天工具
*/

import java.net.*;
import java.io.*;

//发送端
class SendChat implements Runnable
{
	private DatagramSocket sendSocket;
	public SendChat(DatagramSocket sendSocket)
	{
		this.sendSocket = sendSocket;
	}
	public void run()
	{
		try
		{	
			//键盘录入
			BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));
			
			String line = null;
			while((line = bufr.readLine()) != null)
			{		
				if("over". equals(line))
				{
					break;
				}
				//确定数据，并封装成包
				byte[] buf = line.getBytes();
				
				DatagramPacket dp = new DatagramPacket(buf, 0, buf.length, InetAddress.getByName("10.22.72.144"), 30002);
				
				sendSocket.send(dp);
			}

			sendSocket.close();
		}
		catch(Exception e)
		{
			throw new RuntimeException("发送失败");
		}	
	}
}

//接收端
class RecChat implements Runnable
{
	private DatagramSocket recSocket;
	public RecChat(DatagramSocket recSocket)
	{
		this.recSocket = recSocket;
	}
	public void run()
	{
		//定义数据包，用于存储数据
		byte[] buf = new byte[1024];
		while(true)
		{
			try
			{
				DatagramPacket dp = new DatagramPacket(buf, buf.length);
				
				//接收数据
				recSocket.receive(dp);
				
				//获取数据包中的数据
				String ip = dp.getAddress().getHostAddress();
				String data = new String(dp.getData(), 0, dp.getLength());
				
				System.out.println(ip +":" +data);
			}
			catch(Exception e)
			{
				throw new RuntimeException("接收失败");
			}
		}
	}
}


class Chat
{
	public static void main(String[] args) throws Exception
	{
		DatagramSocket sendSocket = new DatagramSocket();
		DatagramSocket recSocket = new DatagramSocket(30002);
		
		new Thread(new SendChat(sendSocket)).start();
		new Thread(new RecChat(recSocket)).start();
	}
}