jmenudemo.java

本java源程序包括了大量的学习程序（共27章）方便大家学习

import java.io.*;
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class JMenuDemo extends JFrame 
{
    private JTextArea editor;
    private JMenuBar menuBar;
    private JMenu fileMenu, editMenu, helpMenu, helpsubjectMenu;
    private JMenuItem fileMenuLoad, fileMenuSave, fileMenuExit, editMenuCut,
                      editMenuCopy, editMenuPaste, helpsubjectMenuNote,
                      helpsubjectMenuCal;
    
    public JMenuDemo()
    {
    	super("菜单栏");
    	setSize(400,300);	
        try 
        {
        	UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch(Exception e) { System.err.println("Can't set look and feel: "+e);}
        //获取内容面板
        Container container = getContentPane();
        
        //创建菜单栏
        menuBar=new JMenuBar();
        menuBar.setBackground(Color.cyan);
        
        addFileMenu();
        addEditMenu();
        addHelpMenu();
        setJMenuBar(menuBar);
        
        editor = new JTextArea();
        container.add(new JScrollPane(editor));
        
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   }

   //创建文件菜单
   private void addFileMenu() 
   {
	   fileMenu=new JMenu("文件(F)");
       fileMenu.setBackground(Color.cyan);     //设置菜单背景颜色
       fileMenu.setForeground(Color.black);
       Font f=new Font("sanserif",Font.PLAIN,12);
       fileMenu.setFont(f);                    //设置菜单中文本的字体
       
       //打开子菜单
       fileMenuLoad=new JMenuItem("打开(O)...  Ctrl+O");
       fileMenuLoad.setFont(f);
       fileMenuLoad.setForeground(Color.black);
       fileMenuLoad.addActionListener(new ActionListener() 
       {
    	   public void actionPerformed(ActionEvent e) 
    	   { loadFile(); }
       });
       fileMenu.add(fileMenuLoad);
       //保存子菜单
       fileMenuSave=new JMenuItem("保存(S)...  Ctrl+S");
       fileMenuSave.setFont(f);
       fileMenuSave.setForeground(Color.black);
       fileMenuSave.addActionListener(new ActionListener() 
       {
           public void actionPerformed(ActionEvent e) 
           { saveFile(); }
       });  
       fileMenu.add(fileMenuSave);         //向菜单JMenu组建对象中,加入菜单项JMenuItem的组建对象

       fileMenu.addSeparator();
       //退出子菜单
       fileMenuExit=new JMenuItem("退出(X)");
       fileMenuExit.setFont(f);
       fileMenuExit.setForeground(Color.black);
       fileMenuExit.addActionListener(new ActionListener() 
       {
           public void actionPerformed(ActionEvent e) 
           { System.exit(0); }
       });
       fileMenu.add(fileMenuExit);      //向菜单JMenu组建对象中,加入菜单项JMenuItem组建对象 
       menuBar.add(fileMenu);           //向菜单栏JMenuBar组建对象中,加入菜单JMenu组建对象
   }

   //创建编辑菜单
   private void addEditMenu() 
   {
	   editMenu=new JMenu("编辑(E)");
       Font f=new Font("sanserif",Font.PLAIN,12);
       editMenu.setFont(f);
       editMenu.setBackground(Color.cyan);
       editMenu.setForeground(Color.black);
       //剪切子菜单 
       editMenuCut=new JMenuItem("剪切(T)  Ctrl+X");
       editMenuCut.setFont(f);
       editMenuCut.setForeground(Color.black);
       editMenuCut.addActionListener(new ActionListener() 
       {
           public void actionPerformed(ActionEvent e) 
           { cut(); }
       });
       editMenu.add(editMenuCut);
       //复制子菜单
       editMenuCopy=new JMenuItem("复制(C)  Ctrl+C");
       editMenuCopy.setFont(f);
       editMenuCopy.setForeground(Color.black);
       editMenuCopy.addActionListener(new ActionListener() 
       {
           public void actionPerformed(ActionEvent e)
           { copy();}
       });
       editMenu.add(editMenuCopy);
       //粘贴子菜单
       editMenu.addSeparator();
       editMenuPaste=new JMenuItem("粘贴(P)  Ctrl+V");
       editMenuPaste.setFont(f);
       editMenuPaste.setForeground(Color.black);
       editMenuPaste.addActionListener(new ActionListener() 
       {
           public void actionPerformed(ActionEvent e) 
           { paste(); }
       });
       editMenu.add(editMenuPaste);
       
       menuBar.add(editMenu);
    }
   
   //创建帮助菜单
   private void addHelpMenu() 
   {
	   helpMenu=new JMenu("帮助(H)");
	   Font f=new Font("sanserif",Font.PLAIN,12);
       helpMenu.setFont(f);
       helpMenu.setBackground(Color.cyan);
       helpMenu.setForeground(Color.black);

       helpsubjectMenu=new JMenu("帮助主题(H)  Ctrl+H");
       helpsubjectMenu.setFont(f);
       helpsubjectMenu.setBackground(Color.cyan);
       helpsubjectMenu.setForeground(Color.black);
   
       helpsubjectMenuNote=new JMenuItem("关于记事本(A)  Ctrl+A");
       helpsubjectMenuNote.setFont(f);
       helpsubjectMenuNote.setForeground(Color.black);
 
       helpsubjectMenuCal=new JMenuItem("关于计算器(C)  Ctrl+R");
       helpsubjectMenuCal.setFont(f);
       helpsubjectMenuCal.setForeground(Color.black);
       
       helpsubjectMenu.add(helpsubjectMenuNote);
       helpsubjectMenu.addSeparator();   
       helpsubjectMenu.add(helpsubjectMenuCal);
       
       helpMenu.add(helpsubjectMenu);
       
       menuBar.add(helpMenu);
   }
   
   //打开文件
   private void loadFile() {
	   JFileChooser fc=new JFileChooser();
       int returnVal=fc.showOpenDialog(this);
       if(returnVal==JFileChooser.APPROVE_OPTION) 
       {
    	   File file=fc.getSelectedFile();
           try 
           {
              editor.read(new FileReader(file),null);
           }catch(IOException exp){}
       }
   }
   
   //保存文件
   private void saveFile() 
   {
	   JFileChooser fc=new JFileChooser();
       int returnVal=fc.showSaveDialog(this);
       if(returnVal==JFileChooser.APPROVE_OPTION) 
       {
           File file=fc.getSelectedFile();
           try 
           {
        	  editor.write(new FileWriter(file));
           }catch(IOException exp){}
       }
   }
   
   //实现复制功能
   private void copy() 
   {
     editor.copy();
     editor.requestFocus();
   }
   //实现粘贴功能
   private void paste() 
   {
     editor.paste();
     editor.requestFocus();
   }
   //实现剪切功能
   private void cut() 
   {
     editor.cut();
     editor.requestFocus();
   }
   
   public static void main(String[] args) 
   {
	   JMenuDemo application = new JMenuDemo();
   }
 }