JAVA 多线程实现聊天（UDP通信 ）

/*
 * UDP实现相互传递消息
 * 
 */
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

/*
 * 客服端/发送端
 */
class Send implements Runnable{
	private DatagramPacket dPacket;
	private DatagramSocket dSocket;
    public Send(DatagramSocket dSocket)
    {
    	this.dSocket=dSocket;
    }
	@Override
	public void run() {
		// TODO Auto-generated method stub
		try {
			BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(System.in));//从键盘读取数据
			String string;
			while ((string=bufferedReader.readLine())!=null) {//循环读取
				if (string.equals("Bye")) 
				{
				System.err.println("我下线了");
				System.exit(0);
				
				}
				byte []buf=string.getBytes();//将输入的字符串转换为字节数组
				/*
				 * 获取本机ＩＰ(外网ＩＰ，我是发送到本机IP,也可以试试其它IP)，然后从本机发送到18888的端口（在这里也就是发送到我自己的18888端口）
				 */
				String IP=InetAddress.getLocalHost().getHostAddress().toString();
				dPacket=new DatagramPacket(buf, buf.length, InetAddress.getByName(IP), 18888);
				dSocket.send(dPacket);
			}
		} catch (Exception e) {
			// TODO: handle exception
			System.err.println("发送数据失败");
			e.printStackTrace();
		}
	}
	
}
/*
 *服务器/ 接受端
 */
class Recive implements Runnable{
	private DatagramPacket dPacket;
	private DatagramSocket dSocket;
    public Recive(DatagramSocket dSocket)
    {
    	this.dSocket=dSocket;
    }
	@Override
	public void run() {
		// TODO Auto-generated method stub
		while (true) {
			byte[] buf=new byte[1024];
			dPacket=new DatagramPacket(buf, buf.length);
			try {
				dSocket.receive(dPacket);
				String IP=dPacket.getAddress().getHostAddress();
				String data=new String(dPacket.getData(), 0, dPacket.getLength());
				int portString=dPacket.getPort();
				System.out.println("IP:"+IP+"端口:"+portString+"\n"+data);
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			
			
		}
	}
	
}
public class test {

	/**
	 * @param args
	 */
	public static void main(String[] args) throws Exception{
		// TODO Auto-generated method stub
	
      new Thread(new Send(new DatagramSocket())).start();
    
      new Thread(new Recive(new DatagramSocket(18888))).start();
	}

}