example8_5.java

书中的例题

  /* 英汉小词典 */
 import java.io.*;
 import javax.swing.*;
 import java.awt.*;
 import java.awt.event.*;
 class InputArea extends Panel implements ActionListener
 {
   File f=null;
   RandomAccessFile out;
   TextField word,note;
   Button button;
   InputArea(File f)
   {   setBackground(Color.cyan);
       this.f=f;
       word=new TextField(8);
       note=new TextField(8); 
       button=new Button("录入");
       button.addActionListener(this);
       add(new Label("输入单词"));add(word);
       add(new Label("输入解释"));add(note);
       add(button);
   }
   public void actionPerformed(ActionEvent e)
   { 
	try{
        RandomAccessFile out=new RandomAccessFile(f,"rw");
        if(f.exists())
          {  long length=f.length();
             out.seek(length);
          }
        out.writeUTF("单词:"+word.getText());
        out.writeUTF("解释:"+note.getText());
        out.close();
       }
     catch(IOException ee){}
   }
 }

 class RandWin extends Frame implements ActionListener
 {
   File file=null;
   MenuBar bar;
   Menu fileMenu;
   MenuItem 录入,显示;
   TextArea txt;
   InputArea inputMessage;
   CardLayout card=null; //卡片式布局.
   Panel pCenter;
   Button btn=new Button("显示");
   RandWin()
   { 
    super("英汉小词典");
	file=new File("英汉小词典.txt");
    inputMessage=new InputArea(file);
    txt=new TextArea(5,50); 
    card=new CardLayout();
    pCenter=new Panel();
    setLayout(new FlowLayout());
    add(inputMessage);
    add(btn);
    add(txt);
    btn.addActionListener(this);
    addWindowListener(new WindowAdapter()
       { public void windowClosing(WindowEvent e)
           {
              System.exit(0);
      	   }
       });
    setVisible(true);
    setBounds(100,50,380,200);
    validate();
   }
   public void actionPerformed(ActionEvent e)
   {
	int number=1;
    try{
		RandomAccessFile in=new RandomAccessFile(file,"r");
        String 单词=null; 
        while((单词=in.readUTF())!=null)   
          {  txt.append("\n"+number+" "+单词);
             txt.append("   "+in.readUTF());  //读取汉语解释.
             txt.append("\n------------------------- ");
             number++;
          }
        in.close();
       }
    catch(Exception ee){}
   }
 }
  
public class  Example8_5
{
  public static void main(String args[])
   {  new RandWin();  }
}