用Java写的一个记事本的小程序，实现了新建，打开，另存为，删除，复制，剪切，粘贴，查找和替换一些菜单功能，先看效果图吧～
打开文本文件
下面贴上完整代码，代码里面有详细注释
import java.awt.FileDialog; import java.awt.GridLayout; import java.awt.Toolkit; import java.awt.datatransfer.Clipboard; import java.awt.datatransfer.DataFlavor; import java.awt.datatransfer.StringSelection; import java.awt.datatransfer.Transferable; import java.awt.datatransfer.UnsupportedFlavorException; import java.awt.event.*; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.File; import java.io.FileDescriptor; import java.io.FileReader; import java.io.FileWriter; import java.io.FilenameFilter; import java.io.IOException; import java.io.PrintWriter; import java.io.Writer; import javax.swing.*; import javax.swing.event.*; import javax.swing.filechooser.FileNameExtensionFilter; import javax.swing.undo.UndoManager; /* * 记事本----独孤我---2011年12月5日----绿岛网络办公室 * 转载请注明出处* * * */ public class Notepad extends JFrame implements ActionListener { /** * */ private static final long serialVersionUID = 1L; JPanel pl=new JPanel(); JTextArea myarea=new JTextArea(); //相关变量 int start=0;//查找开始位置 int end=0;//查找结束位置 private String filename; //打开的文件名 String textContent="";//编辑框中的内容 private Writer file_writer; UndoManager undoManager = new UndoManager();//撤销管理器 public Notepad() { initComponment();//面板初始化 } private void initComponment() { //菜单栏 JMenuBar mb=new JMenuBar(); //弹出菜单 final JPopupMenu myPopMenu=new JPopupMenu(); JMenuItem copy_pop=new JMenuItem("复制"); JMenuItem cut_pop=new JMenuItem("剪切"); JMenuItem paste_pop=new JMenuItem("粘贴"); JMenuItem delete_pop=new JMenuItem("删除"); JMenuItem exit_pop=new JMenuItem("退出"); myPopMenu.add(cut_pop); myPopMenu.add(copy_pop); myPopMenu.add(delete_pop); myPopMenu.add(paste_pop); myPopMenu.add(exit_pop); cut_pop.addActionListener(this); copy_pop.addActionListener(this); delete_pop.addActionListener(this); paste_pop.addActionListener(this); exit_pop.addActionListener(this); //菜单 JMenu file=new JMenu("文件"); JMenu edit=new JMenu("编辑"); JMenu help=new JMenu("帮助"); //子菜单 JMenuItem new_file=new JMenuItem("新建"); JMenuItem open=new JMenuItem("打开"); JMenuItem save=new JMenuItem("保存"); JMenuItem save_as=new JMenuItem("另存为"); JMenuItem exit=new JMenuItem("退出"); JMenuItem search=new JMenuItem("查找和替换"); JMenuItem copy=new JMenuItem("复制"); JMenuItem cut=new JMenuItem("剪切"); JMenuItem paste=new JMenuItem("粘贴"); JMenuItem delete=new JMenuItem("删除"); //绑定监听事件 new_file.addActionListener(this); open.addActionListener(this); save.addActionListener(this); save_as.addActionListener(this); exit.addActionListener(this); copy.addActionListener(this); cut.addActionListener(this); paste.addActionListener(this); delete.addActionListener(this); search.addActionListener(this); //将菜单和相应的子菜单添加到菜单栏 file.add(open); file.add(new_file); file.add(save); file.add(save_as); file.addSeparator(); file.add(exit); edit.add(copy); edit.add(cut); edit.add(paste); edit.add(delete); edit.add(search); mb.add(file); mb.add(edit); mb.add(help); //给文本区域添加滚动条 myarea.add(myPopMenu); JScrollPane scrollpane=new JScrollPane(myarea); //主窗口 setTitle("记事本"); setSize(600,400); setLocation(400,300); setJMenuBar(mb); //add("Center",myarea); add(scrollpane); // add(myPopMenu); //窗口监听 addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent evt) { if(!myarea.getText().equals(textContent)) { int result=JOptionPane.showConfirmDialog(null,"文件内容已改变，确认保存退出吗？","警告",1); if(result==JOptionPane.OK_OPTION) { save(); System.exit(0); } } else System.exit(0); } }); //鼠标监听 myarea.addMouseListener(new MouseAdapter() { public void mousePressed(MouseEvent e) { int mods=e.getModifiers(); //鼠标右键 if((mods&InputEvent.BUTTON3_MASK)!=0){ //弹出菜单 myPopMenu.show(e.getComponent(),e.getX(),e.getY()); } } }); } @Override public void actionPerformed(ActionEvent e) { // TODO Auto-generated method stub try { if(e.getActionCommand()=="新建") { myarea.setText(""); } else if(e.getActionCommand()=="打开") { FileDialog fileDialog=new FileDialog(this,"打开文件",FileDialog.LOAD); fileDialog.setFile("*.txt"); fileDialog.setVisible(true); if(fileDialog.getFile()!=null) { filename=fileDialog.getDirectory()+fileDialog.getFile();//获得文件名 //读取文件 FileReader file_reader=new FileReader(filename);//此处必须要捕获异常 BufferedReader br=new BufferedReader(file_reader); String temp=""; while(br.ready())//判断缓冲区是否为空，非空时返回true { int c=br.read(); temp+=(char)c; } myarea.setText(temp); br.close(); file_reader.close(); textContent=myarea.getText(); setTitle("记事本-"+filename); } } else if(e.getActionCommand()=="保存") { save(); } else if(e.getActionCommand()=="另存为") { FileDialog fileDialog=new FileDialog(this,"另存为",FileDialog.SAVE); fileDialog.setFile("*.txt"); fileDialog.setVisible(true); if(fileDialog.getFile()!=null) { //File temp=new File(file.getAbsolutePath()+".txt"); //file.renameTo(temp); //写入文件 FileWriter fw=new FileWriter(fileDialog.getDirectory()+fileDialog.getFile()); BufferedWriter bw=new BufferedWriter(fw); PrintWriter pw=new PrintWriter(bw); pw.print(myarea.getText()); textContent=myarea.getText(); pw.close(); bw.close(); fw.close(); } } else if(e.getActionCommand()=="退出") { if(!myarea.getText().equals(textContent)) { int result=JOptionPane.showConfirmDialog(null,"文件内容已改变，确认保存退出吗？","警告",1); if(result==JOptionPane.OK_OPTION) { save(); System.exit(0); } } else System.exit(0); } else if(e.getActionCommand()=="查找和替换") { //查找对话框 JDialog search=new JDialog(this,"查找和替换"); search.setSize(200, 100); search.setLocation(450,350); JLabel label_1=new JLabel("查找的内容"); JLabel label_2=new JLabel("替换的内容"); final JTextField textField_1=new JTextField(5); final JTextField textField_2=new JTextField(5); JButton buttonFind=new JButton("查找下一个"); JButton buttonChange=new JButton("替换"); JPanel panel=new JPanel(new GridLayout(2,3)); panel.add(label_1); panel.add(textField_1); panel.add(buttonFind); panel.add(label_2); panel.add(textField_2); panel.add(buttonChange); search.add(panel); search.setVisible(true); //为查找下一个 按钮绑定监听事件 buttonFind.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { // TODO Auto-generated method stub String findText=textField_1.getText();//查找的字符串 String textArea=myarea.getText();//当前文本框的内容 start=textArea.indexOf(findText,end); end=start+findText.length(); if(start==-1)//没有找到 { JOptionPane.showMessageDialog(null,"没找到"+findText,"记事本",JOptionPane.WARNING_MESSAGE); myarea.select(start, end); } else { myarea.select(start,end); } } }); //为替换按钮绑定监听时间 buttonChange.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent e) { // TODO Auto-generated method stub String changeText=textField_2.getText();//替换的字符串 myarea.select(start, end); myarea.replaceSelection(changeText); myarea.select(start, end); } }); } else if(e.getActionCommand()=="复制") { copy(); } else if(e.getActionCommand()=="粘贴") { paste(); } else if(e.getActionCommand()=="剪切") { cut(); } else if(e.getActionCommand()=="删除") { delete(); } } catch(Exception ex) { ex.printStackTrace(); } } public static void main(String[] args) { new Notepad().setVisible(true); } private void save() { try { File file=new File(filename); FileWriter file_writer; file_writer = new FileWriter(file); BufferedWriter bw=new BufferedWriter(file_writer); PrintWriter pw=new PrintWriter(bw);//如果直接向文件中输入而不是输入缓冲区，效率低下 pw.print(myarea.getText()); textContent=myarea.getText(); pw.close(); bw.close(); file_writer.close(); } catch(Exception e) { e.printStackTrace(); } } private void cut() { copy(); delete(); } private void copy() { if(myarea.getSelectedText()==null) { JOptionPane.showMessageDialog(null, "你没有选中任何文字！","记事本",JOptionPane.WARNING_MESSAGE); } Clipboard clipBoard= Toolkit.getDefaultToolkit().getSystemClipboard(); StringSelection stringSelection=new StringSelection(myarea.getSelectedText()); clipBoard.setContents(stringSelection, null); } private void paste() throws UnsupportedFlavorException, IOException { String content_copy=""; //构造系统剪切板 Clipboard clipBoard= Toolkit.getDefaultToolkit().getSystemClipboard(); //获取剪切板内容 Transferable content=clipBoard.getContents(null); if(content!=null) { //检查是否是文本类型 if(content.isDataFlavorSupported(DataFlavor.stringFlavor)) { content_copy=(String) content.getTransferData(DataFlavor.stringFlavor); //判断文本框中有无文字选中 if(myarea.getSelectedText()!=null) { myarea.replaceSelection(content_copy); } else { myarea.insert(content_copy, myarea.getSelectionStart()); } } } else JOptionPane.showMessageDialog(null, "系统剪贴板中无内容！","记事本",JOptionPane.WARNING_MESSAGE); } private void delete() { myarea.replaceSelection(""); } }