client.java

Java网络课程设计作业。用c/s模式实现。

import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
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;

   // 客户端构造函数
   public Client( String host )
   {
      super( "客户端Client" );

      // 指定客户端连接的主机地址
      chatServer = host;

      Container container = getContentPane();

      // 消息显示区
      displayArea = new JTextArea();
      container.add( new JScrollPane( displayArea ),
         BorderLayout.CENTER );
         
      // 建立一个单文本行发送消息给主机
      enterField = new JTextField();
      enterField.setEnabled( false );
          
          // 注册回车发送消息事件
      enterField.addActionListener(new ActionListener() {
            public void actionPerformed( ActionEvent event )
            {
               sendData( event.getActionCommand() );
             
            }

         }  ); 

      container.add( enterField, BorderLayout.SOUTH );

      setSize( 400, 300 );
      setVisible( true );
   }

   // 连接到服务端并接受服务端的消息
   public void runClient() 
   {
      
      try {

         //建立一个到服务端的连接
      displayArea.setText( "正在连接服务端......\n" );

      
      client = new Socket( 
         InetAddress.getByName( chatServer ), 5000 );

      displayArea.append( "连接到主机: " +
         client.getInetAddress().getHostName() );

         // 获得输入输出流
      output = new ObjectOutputStream(
         client.getOutputStream() );
      output.flush();

      input = new ObjectInputStream(
         client.getInputStream() );

      displayArea.append( "\n获得输入输出流\n" );

         // 接受消息并显示在displayArea
      // 使发送消息区能编辑
      enterField.setEnabled( true );

      do {

         // 读取服务端的消息并在消息显示区显示
         try {
            message = ( String ) input.readObject();
            displayArea.append( "\n" + message );
            displayArea.setCaretPosition(
               displayArea.getText().length() );
         }

         // 捕获异常
         catch ( ClassNotFoundException classNotFoundException ) {
            displayArea.append( "\nUnknown object type received" );
         }

      } while ( !message.equals( "服务端：离线" ) );

         // 关闭连接
      displayArea.append( "\n关闭连接" );
      output.close();
      input.close();
      client.close();
      }

      
      catch ( EOFException eofException ) {
         System.out.println( "服务器关闭了连接" );
      }

      
      catch ( IOException ioException ) {
         ioException.printStackTrace();
      }
   }



  

 

   // 发送消息到服务端
   private void sendData( String message )
   {
   
      try {
         output.writeObject( "客户端说：" + message );
         output.flush();
         displayArea.append( "\n客户端说：" + message );
      }
      catch ( IOException ioException ) {
         displayArea.append( "\nError writing object" );
      }
   }

   // 主函数
   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();
   }

}