java 仿window记事本

import java.io.*;import java.awt.*;import java.awt.event.*;public class NoteBook extends Frame implements ActionListener{private TextArea text=new TextArea();private Menu menu=new Menu("文件");private MenuItem openitem=new MenuItem("打开");private MenuItem saveitem=new MenuItem("保存");private MenuItem closeitem=new MenuItem("关闭");public NoteBook(){super("NoteBook");menu.add(openitem);openitem.addActionListener(this);menu.addSeparator();menu.add(saveitem);saveitem.addActionListener(this);menu.addSeparator();menu.add(closeitem);closeitem.addActionListener(this);MenuBar menubar=new MenuBar();menubar.add(menu);setMenuBar(menubar);setLayout(new BorderLayout());add("Center",text);text.setEditable(true);setSize(400,400);setVisible(true);}public void actionPerformed(ActionEvent ae){if(ae.getSource()==openitem){FileDialog fd=new FileDialog(this,"Open File",FileDialog.LOAD);fd.setVisible(true);if(fd.getFile()!=null){File file=new File(fd.getDirectory()+fd.getFile());if(file.exists()){readFile(file.toString());}}}else if(ae.getSource()==closeitem){System.exit(0);}else if(ae.getSource()==saveitem){FileDialog fd=new FileDialog(this,"保存文件",FileDialog.SAVE);fd.setVisible(true);if(fd.getFile()!=null){File file=new File(fd.getDirectory()+fd.getFile());saveFile(file.toString());}}}private void readFile(String file) {// TODO Auto-generated method stubtext.setText("");try{BufferedReader in=new BufferedReader(new FileReader(file));String line;while((line=in.readLine())!=null){text.append(line+'\n');}text.setCaretPosition(0);in.close();}catch(IOException ioe){System.out.println(ioe.toString());}}private void saveFile(String file){File savefile=new File(file);if(!savefile.exists()){try {savefile.createNewFile();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}try {PrintWriter out=new PrintWriter(new FileWriter(savefile));out.println(text.getText());out.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}public static void main(String[] args){NoteBook note=new NoteBook();}}