一个关于java数据报做的简单聊天的问题

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问题补充：代码太乱了- -再发一遍
public class Server extends JFrame implements Runnable
{
final static int MEMBER_COUNT = 2,PORT_NUMBER =5000;//最大连接数目
   private JTextArea displayArea; // displays packets received
   private DatagramSocket socket; // socket to connect to client
   Member[] members;
   int number = 0;//已经连接到的client数目
   // 创建 GUI 和 DatagramSocket
   public Server()
   {
      super( "Server" );
      members =new Member[Server.MEMBER_COUNT];
      displayArea = new JTextArea(); // create displayArea
      add( new JScrollPane( displayArea ), BorderLayout.CENTER );
      setSize( 400, 300 ); // set size of windows
      this.addWindowListener(new WindowAdapter(){

@Override
public void windowClosing(WindowEvent e) {
// TODO Auto-generated method stub
socket.close();
}

      });
      setVisible( true ); // show window

      try // create DatagramSocket for sending and receiving packets
      {
         socket = new DatagramSocket( Server.PORT_NUMBER );
      } // end try
      catch ( SocketException socketException )
      {
         socketException.printStackTrace();
         System.exit( 1 );
      } // end catch
   } // end Server constructor
   //连接到服务器
   public boolean connectTo(InetAddress address)
   {
for(int i=0;i<Server.MEMBER_COUNT;i++)
{
if(members[i]==null)
{
members[i] = new Member(Server.PORT_NUMBER,address);
number++;
this.displayMessage("连接成功");
return true;//连接成功
}
}
return false;//连接失败
   }
   private boolean isFirst(InetAddress a)//是否存在这个ip
   {
   for(int i=0;i<Server.MEMBER_COUNT;i++)
   {
   if(members[i]!=null&&a.equals(members[i].address)) return false;//已经存在
   }
   return true;//是第一次发送
   }
   // 等待接收并将接收到的包发送
   public void waitForPackets()
   {
      while ( true )
      {
         try // receive packet, display contents, return copy to client
         {
            byte data[] = new byte[ 100 ]; // set up packet
            DatagramPacket receivePacket =
               new DatagramPacket( data, data.length );

            socket.receive( receivePacket ); // wait to receive packet
     
            if(isFirst(receivePacket.getAddress()))//第一次发送
            this.connectTo(receivePacket.getAddress());//连接
            System.out.printf("send \"%s\" to client\n", new String(receivePacket.getData(),
            0,receivePacket.getLength()));
            sendPacketToClient( receivePacket ); // send packet to client
         } // end try
         catch ( IOException ioException )
         {
            displayMessage( ioException.toString() + "\n" );
            ioException.printStackTrace();
         } // end catch
      } // end while
   } // end method waitForPackets

   // echo packet to client
   private void sendPacketToClient( DatagramPacket receivePacket )
      throws IOException
   {


      // create packet to send
      DatagramPacket sendPacket;
      for(int i=0;i<Server.MEMBER_COUNT;i++)
      {
      if(members[i]!=null)
      {
      sendPacket = new DatagramPacket(receivePacket.getData(),
      receivePacket.getLength(),members[i].address,members[i].port);
      socket.send( sendPacket );
      }
      }  // send packet to client

   } // end method sendPacketToClient

   // manipulates displayArea in the event-dispatch thread
   private void displayMessage( final String messageToDisplay )
   {
      SwingUtilities.invokeLater(
         new Runnable()
         {
            public void run() // updates displayArea
            {
               displayArea.append( messageToDisplay ); // display message
            } // end method run
         } // end anonymous inner class
      ); // end call to SwingUtilities.invokeLater
   } // end method displayMessage
@Override
public void run()
{
// TODO Auto-generated method stub
waitForPackets();
}

} // end class Server
public class Client extends JFrame implements Runnable
{
   private JTextField enterField; // for entering messages
   private JTextArea displayArea; // for displaying messages
   private DatagramSocket socket; // socket to connect to server
   String name;
   // set up GUI and DatagramSocket
   public Client(String myname)
   {
      super( myname );
      name = myname;
      enterField = new JTextField( "Type message here" );
      enterField.addActionListener(
         new ActionListener()
         {
            public void actionPerformed( ActionEvent event )
            {
               try // create and send packet
               {
                  // get message from textfield
                  String message = event.getActionCommand();
             
                  byte data[] = message.getBytes(); // convert to bytes
        
                  // create sendPacket
                  DatagramPacket sendPacket = new DatagramPacket( data,
                     data.length, InetAddress.getLocalHost(), 5000 );
                  System.out.printf("send to server\"%s\"\n", new String(sendPacket.getData(),0,sendPacket.getLength()));
                  socket.send( sendPacket ); // send packet
                  enterField.setText("");
               } // end try
               catch ( IOException ioException )
               {
                  displayMessage( ioException.toString() + "\n" );
                  ioException.printStackTrace();
               } // end catch
            } // end actionPerformed
         } // end inner class
      ); // end call to addActionListener

      add( enterField, BorderLayout.NORTH );

      displayArea = new JTextArea();
      add( new JScrollPane( displayArea ), BorderLayout.CENTER );

      setSize( 400, 300 ); // set window size
      setVisible( true ); // show window

      try // create DatagramSocket for sending and receiving packets
      {
         socket = new DatagramSocket();
      } // end try
      catch ( SocketException socketException )
      {
         socketException.printStackTrace();
         System.exit( 1 );
      } // end catch
   } // end Client constructor

   // wait for packets to arrive from Server, display packet contents
   public void waitForPackets()
   {

      while ( true )
      {
         try // receive packet and display contents
         {
            byte data[] = new byte[ 100 ]; // set up packet
            DatagramPacket receivePacket = new DatagramPacket(
               data, data.length );

            socket.receive( receivePacket ); // wait for packet
            System.out.println("receive from server ok");
            // display packet contents
            displayMessage(new String( receivePacket.getData(),
                  0, receivePacket.getLength() ) );
         } // end try
         catch ( IOException exception )
         {
            displayMessage( exception.toString() + "\n" );
            exception.printStackTrace();
         } // end catch
      } // end while
   } // end method waitForPackets

   // manipulates displayArea in the event-dispatch thread
   private void displayMessage( final String messageToDisplay )
   {
      SwingUtilities.invokeLater(
         new Runnable()
         {
            public void run() // updates displayArea
            {
               displayArea.append( messageToDisplay );
            } // end method run
         }  // end inner class
      ); // end call to SwingUtilities.invokeLater
   } // end method displayMessage

@Override
public void run() {
// TODO Auto-generated method stub
waitForPackets();
}
}  // end class Client
public class Member
{
int port;//端口号码
InetAddress address;//地址
Member(int port,InetAddress  address)
{
this.port = port;
this.address = address;
}
}
public class Member
{
int port;//端口号码
InetAddress address;//地址
Member(int port,InetAddress  address)
{
this.port = port;
this.address = address;
}
}