写了一个UDP的聊天系统，但是无法实现广播，请各位帮忙看看
[size=18px]sever端：[/size]
package UDPChatRoom;
import java.net.*;
import java.util.*;
public class UDPChatRoomServer {

/**
* @param args
*/
public static void main(String[] args) throws Exception{
// TODO Auto-generated method stub
HashSet set=new HashSet();
DatagramSocket ds=new DatagramSocket(9000);
while(true){
byte[] bs1=new byte[100];
DatagramPacket letter1=new DatagramPacket(bs1,0,bs1.length);
ds.receive(letter1);
InetAddress ip=letter1.getAddress();
set.add(ip);
int port=letter1.getPort();
byte[] bs2=letter1.getData();
int offset=letter1.getOffset();
int length=letter1.getLength();
String str=new String(bs2,offset,length);

byte[] bs3=str.toUpperCase().getBytes();
for(Object o:set){
System.out.println(o);
DatagramPacket letter2=new DatagramPacket(bs3,0,bs3.length,(InetAddress)o,port);
ds.send(letter2);
}
}
}

}

[size=18px]client端：[/size]

package UDPChatRoom;
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.net.*;

public class UDPChatRoomClient {
JTextField jtf;
JTextArea jta;
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
UDPChatRoomClient c=new UDPChatRoomClient();
}

public UDPChatRoomClient(){
initGUI();
initNet();
}

public void initGUI(){
JFrame j=new JFrame("Chat");
j.setSize(400,300);
j.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jta=new JTextArea();
jta.setEditable(false);
JScrollPane jsp=new JScrollPane(jta);
jtf=new JTextField();
j.add(jsp,BorderLayout.CENTER);
j.add(jtf,BorderLayout.SOUTH);
j.setVisible(true);




}

public void initNet(){
try {

final DatagramSocket ds=new DatagramSocket();
jtf.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){

try {
byte[] bs1=jtf.getText().getBytes();
jtf.setText("");
String sss="192.168.0.12";
InetAddress ip=InetAddress.getByName(sss);
DatagramPacket letter1=new DatagramPacket(bs1,0,bs1.length,ip,9000);
ds.send(letter1);
} catch (UnknownHostException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
});

while(true){

DatagramPacket letter2=new DatagramPacket(new byte[100],0,100);
ds.receive(letter2);
byte[] bs2=letter2.getData();
int length=letter2.getLength();
int offset=letter2.getOffset();
String str=new String(bs2,offset,length);
jta.append(str+"\n");
}

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
} 


}
}



我没法实现一个人说话，每个客户端的JTextArea上都显示出来，不知道哪错了，请教大家，先谢谢了

------解决方案--------------------
给你简单改造了一下,你看看
服务端

Java code

package UDPChatRoom;

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.MulticastSocket;

public class UDPChatRoomServer {

    public static final int UDP_SERVER_PORT = 9001;
    public static final int UDP_BOARD_PORT = 9000;
    
    public static void main(String[] args) throws Exception {
        //create boardcast socket and add to group
        MulticastSocket boradCast = new MulticastSocket(UDP_BOARD_PORT);
        InetAddress boradIP = InetAddress.getByName("224.168.0.114");
        boradCast.joinGroup(boradIP);
        //create udp server socket to get data from client
        DatagramSocket serverSocket = new DatagramSocket(9001);
        while (true) {
            byte[] bs1 = new byte[100];
            DatagramPacket letter1 = new DatagramPacket(bs1, 0, bs1.length);
            // receive data by UDP
            serverSocket.receive(letter1); 
            
            byte[] bs2 = letter1.getData();
            int offset = letter1.getOffset();
            int length = letter1.getLength();
            String str = new String(bs2, offset, length);

            byte[] bs3 = str.toUpperCase().getBytes();
            DatagramPacket letter2 = new DatagramPacket(bs3, bs3.length,
                    boradIP, 9000);
            // send received data to group
            boradCast.send(letter2); 
        }
    }
}