m_client.java

用UDP协议实现两台电脑间的相互对话通信

// M_Client.java
//
// Set up a Client that will read information sent
// from a Server and display the information.
   
// Java core packets
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
 
// Java extension packets
import javax.swing.*;

public class M_Client extends JFrame 
{
      private JTextField enterField;
      private JTextArea displayArea;
      private DatagramPacket inPacket;
      private DatagramPacket outPacket;
      private DatagramSocket mClient;
      private InetAddress sAddr;
      private byte [] inBuffer;
      private byte [] outBuffer;
      private String message = "";
      private InetAddress cAddr;
      private int cPort;


// initialize chatServer and set up GUI
      
      public M_Client(String s)
      {
         super( "Client" );
         
         try
         {
         // set server to which this client connects
         	sAddr=InetAddress.getByName(s);
         }
         catch(UnknownHostException e)
         {
        	System.err.println(e);	
         } 
        
         inBuffer=new byte[100];
   
         Container container = getContentPane();
   
         // create enterField and register listener
         enterField = new JTextField();
         enterField.setEnabled( false );
         enterField.addActionListener(new ActionListener() 
	{
                  // send message to server
               public void actionPerformed( ActionEvent e )
               {
                  sendData( e.getActionCommand() );
               }
   
            }  // end anonymous inner class
   
         ); // end call to addActionListener
  
         container.add( enterField, BorderLayout.NORTH );
  
        // create displayArea
        displayArea = new JTextArea();
        container.add( new JScrollPane( displayArea ),BorderLayout.CENTER );
  
        setSize(500,300);
        setVisible( true );
    }
      
      // connect to server and process messages from server
      public void runClient() 
      {
         // connect to server, get packets process packets
         try
         {             
            mClient=new DatagramSocket();
            
            do
            processPacket();            
            while(!message.equals( "SERVER>>> Byebye" )) ;   
                  
            mClient.close();
         }
  	  
         // server closed connection
         catch ( EOFException eofException ) 
         {
            System.out.println( "Server terminated connection" );
      
        }
// process problems communicating with server
         catch ( IOException ioException ) 
         {
            ioException.printStackTrace();
         }
      }
   
     
     private void processPacket() throws IOException
     {
        // enable enterField so client user can send messages
          enterField.setEnabled( true );
        // process messages sent from server
  
          // read message and display it
           try 
           {
              inPacket= new DatagramPacket(inBuffer,inBuffer.length);
              mClient.receive(inPacket);
              
              cAddr=inPacket.getAddress();
  	     cPort=inPacket.getPort();
  	
  	     displayArea.append( "\nPackage received from: ClientAddress="
  	                    +cAddr.toString()+" at Port "+cPort);   
              
              message =new String(inPacket.getData(),0,inPacket.getLength());
              displayArea.append(message);
              displayArea.setCaretPosition(displayArea.getText().length());
           }
  
          // catch problems reading from server
           catch (IOException e)
          {
              displayArea.append( "\nIOExecption occurred with M_Client" );
          }
  
        
    }  // end method process packet

    
 
     // send message to server
     private void sendData( String message )
     {
        // send object to server
        try 
        {
          outBuffer=("\n阎亚茹>>> " + message).getBytes();
          outPacket=new DatagramPacket(outBuffer ,outBuffer.length,sAddr,8341);
          mClient.send(outPacket);
          
          enterField.setText("");
          displayArea.append( "\n阎亚茹>>> " + message );
          
          
       }
  
        // process problems sending object
        catch ( IOException e )
        {
           displayArea.append( "\nIOException occrred" );
           System.out.println(e);
           e.printStackTrace();
           
        }
     }
// execute application
    public static void main( String args[] )
     {
        M_Client application;
        String s=new String();
        /*try
        {
        	s=InetAddress.getLocalHost().getHostAddress();
        }
        catch(UnknownHostException e)
        {
        	System.err.println(e);	
        } */
        s="219.224.154.228";
        if ( args.length == 0 )
           	application = new M_Client(s);
        else
        	application = new M_Client(args[0]);
        application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE );
  
        application.runClient();
     }
  
  }  // end class Client