udpget.java

聊天程序实现的功能可以是像QQ聊天程序那样点对点的对话

import java.net.*;
import java.awt.*;
import java.awt.event.*;
public  class UDPGet extends Frame  implements ActionListener
{TextArea textArea1=new TextArea();
 Button button1=new Button();
 public static void main(String args[])
{UDPGet get=new UDPGet();
get.setLocation(100,100);
get.setSize(300,200);
get.show();
get.waitForData();
}
public UDPGet()
{try{
      this.setTitle("接收数据报");
      textArea1.setText("");
      button1.setLabel("退出");
      this.add(textArea1,BorderLayout.CENTER);
      this.add(button1,BorderLayout.SOUTH);
      button1.addActionListener(this);
       }
 catch(Exception e){e.printStackTrace();
            }
}

void waitForData()
{
    try
     {
       byte[] buffer=new byte[1024];
       DatagramPacket packet=new DatagramPacket(buffer,buffer.length);
       DatagramSocket socket=new DatagramSocket(9999);
       while(true)
          {socket.receive(packet);
           String s=new String(buffer,0,0,packet.getLength());
           textArea1.append(s+"\n");
           packet=new DatagramPacket(buffer,buffer.length);
          }}
      catch(Exception e){}
     }
 public void actionPerformed(ActionEvent e)
{Component com=(Component)e.getSource();
if(com.equals(button1))
   System.exit(0);
}
 
}