11 多线程实现聊天

气死了，这个错误搞了半天！

package Internet;

import java.net.DatagramSocket;
import java.net.SocketException;

public class Test11_Me {
    public static void main(String[] args) throws Exception {
        new Thread(new Test11_Send(205,"localhost",2000)).start();
        new Thread(new Test11_Receive(2005,"哥哥")).start();
        // 错了半天，才发现：这两个myPort 不能相同，因为一个是发送端口，一个是接收端口，所以不能相同.2001 ！= 2005 ，气死了，调了半天
           //  Address already in use: bind 看出错的解释啊，混蛋
    }
}


////////////////////////////////
package Internet;

import java.net.DatagramSocket;
import java.net.SocketException;

public class Test11_MyBrother {
    public static void main(String[] args) throws Exception {
        new Thread(new Test11_Send(200,"localhost",2005)).start();
        new Thread(new Test11_Receive(2000,"弟弟")).start();
    }
}
//////////////////////////
package Internet;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.*;

public class Test11_Send implements Runnable {
    int myPort,toPort;
    String toIP;
    DatagramSocket socket=null;
    BufferedReader reader =null;


    public Test11_Send(int myPort,String toIP ,int toPort){
        this.myPort = myPort;
        this.toPort = toPort;
        this.toIP = toIP;
        try {
            socket=new DatagramSocket(myPort);
            reader = new BufferedReader(new InputStreamReader(System.in));
        }catch (Exception e){
            e.printStackTrace();
        }
    }

    @Override
    public void run() {
        try {
            // 2. 不断地建立包裹并发送出去： 可以不停地发消息
            // 从控制台键盘读取信息，并且发送出去
            while (true) {
                String msg = reader.readLine();
                //  byte[] data=(byte[])reader;  这里不能强制转换
                DatagramPacket packet = new DatagramPacket(msg.getBytes(), 0, msg.length(), new InetSocketAddress(toIP, toPort));
                socket.send(packet);
                if (msg.equals("bye")) {
                    break;
                } // 结束判定
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        // 3. 关闭
        socket.close();
    }
}
///////////////
package Internet;


import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;

public class Test11_Receive implements Runnable{
    int myPort,toPort;
    DatagramSocket socket=null;
    String str;

    public Test11_Receive( int myPort,String str){
        this.myPort = myPort;
        this.str=str;
        // 1. 创建自己的端口
        try {
            socket = new DatagramSocket(myPort);
        } catch (SocketException e) {
            throw new RuntimeException(e);
        }
    }
    @Override
    public void run() {
        try {

            // 2. 不停地接收包裹：可以不停地接收信息
            while (true){
                byte[] buffer = new byte[1024];
                DatagramPacket packet = new DatagramPacket(buffer,0,buffer.length);
                socket.receive(packet); // 阻塞式接收：有就接收
                String msg=new String(packet.getData(),0,packet.getLength());
                System.out.println(str+":"+msg);
                if (msg.equals("bye")){
                    break;
                }

            }
        }catch (Exception e){
            e.printStackTrace();
        }

        // 3. 关闭
        socket.close(); // 阻塞式接收：不断地接收
    }
}