java GUI简单记事本

代码：

 import java.awt.*;
 import java.awt.event.*;
 import java.io.*;
 class MyMenu
 {
     //定义该窗体所需的组件，方便其他函数引用
     private Frame f;
     private Button btn;  //按钮
     private Button btn1;
     private Label label; //标签
     private TextArea ta ; //文本区域
     private Menu fileMenu; //菜单
     private MenuBar bar;
     private MenuItem openItem,saveItem,closeItem; //子菜单

     private FileDialog openDia,saveDia; //文件对话框
     private File file; //文件
     //构造器
     MyMenu(){
         init();
     }
     public void init(){
         f = new Frame("我的窗体及菜单框架");
         /*（所有静态属性设置)*/
         //对窗体进行基本设置
         f.setBounds(100,50,1200,1000);
         f.setLayout(new FlowLayout());
         f.setBackground(Color.gray);
         //组件(自定义)
         btn      = new Button("退出");
         btn1  = new Button("按钮1");
         label = new Label("这是一个文本",Label.CENTER);
         ta = new TextArea("test",30,70,1);//最后一个参数设置为显示滚动条，1显示垂直滚动条，2显示横向滚动条，0全部显示。

         bar = new MenuBar();
         fileMenu = new Menu("文件");
         //定义菜单项
         openItem = new MenuItem("打开");
         saveItem = new MenuItem("保存");
         closeItem = new MenuItem("退出");
         //将菜单项添加进菜单
         fileMenu.add(openItem);
         fileMenu.add(saveItem);
         fileMenu.addSeparator();
         fileMenu.add(closeItem);
          //将菜单已添加进菜单栏
         bar.add(fileMenu);
         f.setMenuBar(bar);
         //添加文件对话框
         openDia = new FileDialog(f,"我要打开",FileDialog.LOAD);
         saveDia = new FileDialog(f,"我要保存",FileDialog.SAVE);
         //组件属性设置
         label.setBackground(Color.pink);
         label.setFont(new Font("Dialog", Font.BOLD, 12));
         label.setSize(300,200);
         //将组件添加到frame中
         f.add(label);
         f.add(ta);
         f.add(btn);
         f.add(btn1);
         //加载窗体事件（所有响应事件)
         myEvent();

         //显示窗体
         f.setVisible(true);
     }

     private void myEvent(){
         /*规则：
           xxxListener(new xxxAdapter())
                     xxxEvent e
         */
         //窗体关闭事件
         f.addWindowListener(new WindowAdapter()
         {
             public void windowClosing(WindowEvent e)
             {
                 System.exit(0);
             }
         });
         //按钮响应事件
         btn.addActionListener(new ActionListener(){
             public void actionPerformed(ActionEvent e)
             {
                 //按钮响应
                 System.out.println("退出，按钮干的");
                 System.exit(0);
             }
         });
         //按钮1响应事件
         btn1.addActionListener(new ActionListener(){
             public void actionPerformed(ActionEvent e)
             {
                 //获取文本内容并显示
                 String taContent =ta.getText();
                 label.setText(taContent);
             }
         });
         //菜单事件：添加保存活动监听，
         saveItem.addActionListener(new ActionListener()
         {

             public void actionPerformed(ActionEvent e)
             {
                 //保存就是直接开启对话框
                 //if(file==null)
                 //{
                     saveDia.setVisible(true);

                     String dirPath = saveDia.getDirectory();
                     String fileName = saveDia.getFile();
                     if(dirPath==null || fileName==null)
                         return ;
                     file = new File(dirPath,fileName);
                 //}

                 try
                 {
                     BufferedWriter bufw  = new BufferedWriter(new FileWriter(file));

                     String text = ta.getText();

                     bufw.write(text);
                     //bufw.flush();
                     bufw.close();
                 }
                 catch (IOException ex)
                 {
                     throw new RuntimeException();
                 }

             }
         });

         openItem.addActionListener(new ActionListener()
         {
             public void actionPerformed(ActionEvent e)
             {
                 openDia.setVisible(true);
                 String dirPath = openDia.getDirectory();
                 String fileName = openDia.getFile();
 //                System.out.println(dirPath+"..."+fileName);
                 if(dirPath==null || fileName==null)
                     return ;

                 ta.setText("");
                 file = new File(dirPath,fileName);

                 try
                 {
                     BufferedReader bufr = new BufferedReader(new FileReader(file));

                     String line = null;

                     while((line=bufr.readLine())!=null)
                     {
                         ta.append(line+"\r\n");
                     }

                     bufr.close();
                 }
                 catch (IOException ex)
                 {
                     throw new RuntimeException("读取失败");
                 }

             }
         });

         closeItem.addActionListener(new ActionListener()
         {
             public void actionPerformed(ActionEvent e)
             {
                 System.exit(0);
             }
         });
     }

     public static void main(String[] args){
         new MyMenu();
     }
 }

效果：