client.java

一个实现双人玩的圈叉游戏

// Fig 17.5 Client.java
   // Set up a Client that will read information sent
   // from a Server and display the information.
    
    // Java core packages
    import java.io.*;
    import java.net.*;
    import java.awt.*;
    import java.awt.event.*;
  //  import java.net.InetAddress;
   // Java extension packages
   import javax.swing.*;
   
   public class Client extends JFrame {
      private JTextField enterField;
      private JTextArea displayArea;
      private ObjectOutputStream output;
      private ObjectInputStream input;
      private String message = "";
      private String chatServer;
      private Socket client;
// initialize chatServer and set up GUI
      public Client( String host )
      {
         super( "Client" );
   
         // set server to which this client connects
         chatServer = host;
   
         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 event )
               {
                  sendData( event.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( 300, 150 );
         setVisible( true );
      }
   
// connect to server and process messages from server
      public void runClient() 
      {
         // connect to server, get streams, process connection
         try {
   
            // Step 1: Create a Socket to make connection
            connectToServer();
   
            // Step 2: Get the input and output streams
            getStreams();
   
            // Step 3: Process connection
            processConnection();
   
            // Step 4: Close connection
            closeConnection();
         }
   
         // server closed connection
         catch ( EOFException eofException ) {
            System.out.println( "Server terminated connection" );
         }
// process problems communicating with server
         catch ( IOException ioException ) {
            ioException.printStackTrace();
         }
      }
   
      // get streams to send and receive data
      private void getStreams() throws IOException
      {
         // set up output stream for objects
         output = new ObjectOutputStream(
            client.getOutputStream() );
   
         // flush output buffer to send header information
        output.flush();
  
        // set up input stream for objects
        input = new ObjectInputStream(
           client.getInputStream() );
  
        displayArea.append( "\nGot I/O streams\n" );
     }

     // connect to server
     private void connectToServer() throws IOException
     {      
        displayArea.setText( "Attempting connection\n" );
  
        // create Socket to make connection to server
        client = new Socket( 
           InetAddress.getByName( chatServer ), 5000 );
  
        // display connection information
        displayArea.append( "Connected to: " +
           client.getInetAddress().getHostName() );
     }
  
     // process connection with server
     private void processConnection() throws IOException
     {
        // enable enterField so client user can send messages
        enterField.setEnabled( true );
  
// process messages sent from server
        do {
  
           // read message and display it
           try {
              message = ( String ) input.readObject();
              displayArea.append( "\n" + message );
              displayArea.setCaretPosition(
                 displayArea.getText().length() );
           }
  
           // catch problems reading from server
           catch ( ClassNotFoundException classNotFoundException ) {
              displayArea.append( "\nUnknown object type received" );
           }
  
        } while ( !message.equals( "SERVER>>> TERMINATE" ) );
  
     }  // end method process connection
  
// close streams and socket
     private void closeConnection() throws IOException
     {
        displayArea.append( "\nClosing connection" );
        output.close();
        input.close();
        client.close();
     }
  
     // send message to server
     private void sendData( String message )
     {
        // send object to server
        try {
           output.writeObject( "CLIENT>>> " + message );
           output.flush();
           displayArea.append( "\nCLIENT>>>" + message );
        }
  
        // process problems sending object
        catch ( IOException ioException ) {
           displayArea.append( "\nError writing object" );
        }
     }
// execute application
     public static void main( String args[] )
     {
        Client application;
  
        if ( args.length == 0 )
           application = new Client( "127.0.0.1" );
        else
           application = new Client( args[ 0 ] );
 
        application.setDefaultCloseOperation(
           JFrame.EXIT_ON_CLOSE );
  
        application.runClient();
     }
  
  }  // end class Client