Java记录之简易记事本

仿照windows记事本，制作一个记事本软件，实现纯文本文件的新建、打开、保存、另存、复制、粘贴、查找、替换、关于等功能。

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.datatransfer.*;
public class Window extends JFrame implements ActionListener,DocumentListener{
    //系统剪贴板
     Toolkit toolkit=Toolkit.getDefaultToolkit();
     Clipboard clipBoard=toolkit.getSystemClipboard();
     //用来复制粘贴
    //右键弹出菜单项
     JPopupMenu popupMenu;
     JMenuItem popupMenu_Undo,popupMenu_Cut,popupMenu_Copy,popupMenu_Paste,popupMenu_Delete,popupMenu_SelectAll;
     String oldValue;//存放编辑区原来的内容，用于比较文本是否有改动
     boolean isNewFile=true;//是否新文件(未保存过的)
     File currentFile;//当前文件名
     File file = null;
     JMenuBar bar;
     JLabel label;//其他变量
     JMenu files ,edit, form ,look ,help;
     JMenuItem news,open,save, saves, copy ,paste ,find, replace,replaceAll,cut;
     JTextArea editArea;
     
     
     Window(){
         setTitle("记事本");
         files = new JMenu("文件");
         edit = new JMenu("编辑");
         form =new JMenu("格式");
         look =new JMenu("查看");
         help =new JMenu("帮助");
         news = new JMenuItem("新建");
         open = new JMenuItem("打开");
         save = new JMenuItem("保存");
         saves = new JMenuItem("另存");
         copy = new JMenuItem("复制");
         cut = new JMenuItem("剪切");
         paste = new JMenuItem("粘贴");
         find = new JMenuItem("查找");
         replace = new JMenuItem("替换");
        // replaceAll = new JMenuItem("全部替换");
         bar = new JMenuBar();
         
         
         files.add(news);
         news.addActionListener(this);//添加监听器
         files.add(saves);
         saves.addActionListener(this);
         files.add(open);
         open.addActionListener(this);
         
         files.add(save);
         save.addActionListener(this);
         files.add(find);
         find.addActionListener(this);
         form.add(replace);
         replace.addActionListener(this);
        // form.add(replaceAll);
         //replaceAll.addActionListener(this);
         edit.add(copy);
         copy.addActionListener(this);
         edit.add(paste);
         paste.addActionListener(this);
         files.add(cut);
         cut.addActionListener(this);
         bar.add(files);
         bar.add(edit); 
         bar.add(form);
         bar.add(look);
         bar.add(help);
         setJMenuBar(bar);
         
         //文本区
         editArea = new JTextArea(200,300);
         JScrollPane scroll = new JScrollPane (editArea);
         editArea.setWrapStyleWord(true);//设置单词在一行不足容纳时换行
         editArea.setLineWrap(true);//设置文本编辑区自动换行默认为true,即会"自动换行"
         add(editArea);
         
         popupMenu = new JPopupMenu();
         //popupMenu_Undo=new JMenuItem("撤销");
         popupMenu_Cut=new JMenuItem("剪切");
         popupMenu_Copy=new JMenuItem("复制");
        popupMenu_Paste=new JMenuItem("粘帖");
         popupMenu_Delete=new JMenuItem("删除");
         popupMenu_SelectAll=new JMenuItem("全选");
        //向右键菜单添加菜单项和分隔符
        // popupMenu.add(popupMenu_Undo);
         popupMenu.addSeparator();
         popupMenu.add(popupMenu_Cut);
         popupMenu.add(popupMenu_Copy);
         popupMenu.add(popupMenu_Paste);
         popupMenu.add(popupMenu_Delete);
         popupMenu.addSeparator();
         popupMenu.add(popupMenu_SelectAll);
        //文本编辑区注册右键菜单事件
         //popupMenu_Undo.addActionListener(this);
         popupMenu_Cut.addActionListener(this);
         popupMenu_Copy.addActionListener(this);
         popupMenu_Paste.addActionListener(this);
         popupMenu_Delete.addActionListener(this);
         popupMenu_SelectAll.addActionListener(this);
         
         //右键菜单
         editArea.addMouseListener(new MouseAdapter(){
             public void mousePressed(MouseEvent e){ 
         if(e.isPopupTrigger()) //返回此鼠标事件是否为该平台的弹出菜单触发事件
         {popupMenu.show(e.getComponent(),e.getX(),e.getY());}//在组件调用者的坐标空间中的位置 X、Y 显示弹出菜单
         
         checkMenuItemEnabled();//设置剪切，复制，粘帖，删除等功能的可用性
         editArea.requestFocus();//编辑区获取焦点
         }
         public void mouseReleased(MouseEvent e){ 
             if(e.isPopupTrigger()){//返回此鼠标事件是否为该平台的弹出菜单触发事件
          popupMenu.show(e.getComponent(),e.getX(),e.getY());//在组件调用者的坐标空间中的位置 X、Y 显示弹出菜单
         }
         checkMenuItemEnabled();//设置剪切，复制，粘帖，删除等功能的可用性
         editArea.requestFocus();//编辑区获取焦点
         }
         });//文本编辑区注册右键菜单事件结束
         
         
         
        //添加窗口监听器
         addWindowListener(new WindowAdapter()
         { public void windowClosing(WindowEvent e)
         { editArea.requestFocus();
         String currentValue=editArea.getText();
         //System.out.println(oldValue);
         if(currentValue.equals(oldValue)==true)//判断是否为新文件
         { System.exit(0);
         }
         else {
              exitWindowChoose();
         }
         }
         });
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         setVisible(true);
         setBounds(100,50,420,380);
         validate();
         
     }//构造方法结束
     
     
     
     //关闭窗口时判断新建
     public void exitWindowChoose() {
         editArea.requestFocus();
         String currentValue=editArea.getText();
         if(currentValue.equals(oldValue)==true)//判断是否为新文件
         { System.exit(0);
         }
         else{
          int exitChoose=JOptionPane.showConfirmDialog(this,"您的文件尚未保存，是否保存？","退出提示",JOptionPane.YES_NO_CANCEL_OPTION);
         if(exitChoose==JOptionPane.YES_OPTION){
          //boolean isSave=false;
         if(isNewFile){ 
             JFileChooser fileDialog = new JFileChooser();
             int state = fileDialog.showSaveDialog(this);
             if(state == JFileChooser.APPROVE_OPTION) {
                 try {
                     File dir = fileDialog.getCurrentDirectory();
                     String name = fileDialog.getSelectedFile().getName();
                     File file = new File(dir,name);
                     FileWriter fileWriter = new FileWriter(file);
                     BufferedWriter out = new BufferedWriter(fileWriter);
                     out.write(editArea.getText());
                     out.close();
                     fileWriter.close();
                 }
                 catch(IOException e) { }
                                      
         } } } }          
     }
     
     
         
     
    @Override
    public void actionPerformed(ActionEvent e ) {
        if(e.getSource()==copy||e.getSource()==popupMenu_Copy) {//复制粘贴剪切
            editArea.copy();
        }
        if(e.getSource()==popupMenu_SelectAll) {
            editArea.select(0,editArea.getText().length());
        }
        if(e.getSource()==cut||e.getSource()==popupMenu_Cut) {
            editArea.cut();
        }
        if(e.getSource()==paste||e.getSource()==popupMenu_Paste) {
            editArea.paste();
        }
        //打开或新建
        if(e.getSource()==open||e.getSource()==news) {
            editArea.requestFocus();
             String currentValue=editArea.getText();
             if(currentValue.equals(oldValue)==true)//判断是否为新文件
             { System.exit(0);
             }
             else{
              int exitChoose=JOptionPane.showConfirmDialog(this,"您的文件尚未保存，是否保存？","退出提示",JOptionPane.YES_NO_CANCEL_OPTION);
             if(exitChoose==JOptionPane.YES_OPTION){
              //boolean isSave=false;
             if(isNewFile){ 
                 JFileChooser fileDialog = new JFileChooser();
                 int state = fileDialog.showSaveDialog(this);
                 if(state == JFileChooser.APPROVE_OPTION) {
                     try {
                         File dir = fileDialog.getCurrentDirectory();
                         String name = fileDialog.getSelectedFile().getName();
                         File file = new File(dir,name);
                         FileWriter fileWriter = new FileWriter(file);
                         BufferedWriter out = new BufferedWriter(fileWriter);
                         out.write(editArea.getText());
                         out.close();
                         fileWriter.close();
                     }
                     catch(IOException ex) { }
                                          
             }} }
             } 
            }    
        if(e.getSource()==find) {
            final JDialog findDialog=new JDialog(this,"查找",false);//false时允许其他窗口同时处于激活状态(即无模式)
             Container con=findDialog.getContentPane();//返回此对话框的contentPane对象 
             con.setLayout(new FlowLayout(FlowLayout.LEFT));
             JLabel findContentLabel=new JLabel("查找内容：");
             final JTextField findText=new JTextField(15);
             JButton findNextButton=new JButton("查找下一个：");
             final JCheckBox matchCheckBox=new JCheckBox("区分大小写");
             ButtonGroup bGroup=new ButtonGroup();
             final JRadioButton upButton=new JRadioButton("向上");
             final JRadioButton downButton=new JRadioButton("向下");
             downButton.setSelected(true);
             bGroup.add(upButton);
             bGroup.add(downButton);
             /*JRadioButton此类实现一个单选按钮，并可为用户显示其状态。
             与 ButtonGroup 对象配合使用创建一组按钮，一次只能选择其中的一个按钮。
             （创建一个 ButtonGroup 对象并用其 add 方法将 JRadioButton 对象包含在此组中。）*/
             
             //"查找下一个"按钮监听
             findNextButton.addActionListener(new ActionListener()
             { public void actionPerformed(ActionEvent e)//适配器
             { //"区分大小写(C)"的JCheckBox是否被选中
             int k=0,m=0;
             final String str1,str2,str3,str4,strA,strB;
             str1=editArea.getText();
             str2=findText.getText();
             str3=str1.toUpperCase();
             str4=str2.toUpperCase();
             if(matchCheckBox.isSelected())//区分大小写
             { strA=str1;
              strB=str2;
             }
             else//不区分大小写,此时把所选内容全部化成大写(或小写)，以便于查找 
             { strA=str3;
              strB=str4;
             }
             if(upButton.isSelected())
             { 
              if(editArea.getSelectedText()==null)
              k=strA.lastIndexOf(strB,editArea.getCaretPosition()-1);//从零开始，光标位置减一
              else
              k=strA.lastIndexOf(strB, editArea.getCaretPosition()-findText.getText().length()-1); 
              if(k>-1)
              { 
              editArea.setCaretPosition(k);//设置光标位置到那
              editArea.select(k,k+strB.length());//将查找到的内容选择
              }
              else
              { JOptionPane.showMessageDialog(null,"找不到您查找的内容！","查找",JOptionPane.INFORMATION_MESSAGE);
              }
             }
             else if(downButton.isSelected())
             { if(editArea.getSelectedText()==null)
              k=strA.indexOf(strB,editArea.getCaretPosition()+1);
              else
              k=strA.indexOf(strB, editArea.getCaretPosition()-findText.getText().length()+1); 
              if(k>-1)
              { 
              editArea.setCaretPosition(k);
              editArea.select(k,k+strB.length());
              }
              else
              { JOptionPane.showMessageDialog(null,"找不到您查找的内容！","查找",JOptionPane.INFORMATION_MESSAGE);
              }
             }
             }
             });
           //创建"查找"对话框的界面
             JPanel panel1=new JPanel();
             JPanel panel2=new JPanel();
             JPanel panel3=new JPanel();
             JPanel directionPanel=new JPanel();
             directionPanel.setBorder(BorderFactory.createTitledBorder("方向"));
             //设置directionPanel组件的边框;
             //BorderFactory.createTitledBorder(String title)创建一个新标题边框，使用默认边框（浮雕化）
             //、默认文本位置（位于顶线上）、默认调整 (leading) 以及由当前外观确定的默认字体和文本颜色，并指定了标题文本。
             directionPanel.add(upButton);
             directionPanel.add(downButton);
             panel1.setLayout(new GridLayout(2,1));
             panel1.add(findNextButton);
             panel2.add(findContentLabel);
             panel2.add(findText);
             panel2.add(panel1);
             panel3.add(matchCheckBox);
             panel3.add(directionPanel);
             con.add(panel2);
             con.add(panel3);
             findDialog.setSize(410,180);
             findDialog.setResizable(false);//不可调整大小
             findDialog.setLocation(230,280);
             findDialog.setVisible(true);
        }
        if(e.getSource()==replace) {
            final JDialog replaceDialog=new JDialog(this,"替换",false);//false时允许其他窗口同时处于激活状态(即无模式)
            Container con=replaceDialog.getContentPane();//返回此对话框的contentPane对象
            con.setLayout(new FlowLayout(FlowLayout.CENTER));
            JLabel findContentLabel=new JLabel("查找内容(N)：");
            final JTextField findText=new JTextField(15);
            JButton findNextButton=new JButton("查找下一个(F):");
            JLabel replaceLabel=new JLabel("替换为(P)：");
            final JTextField replaceText=new JTextField(15);
            JButton replaceButton=new JButton("替换(R)");
            JButton replaceAllButton=new JButton("全部替换(A)");
            JButton cancel=new JButton("取消");
            cancel.addActionListener(new ActionListener()
            { public void actionPerformed(ActionEvent e)
            { replaceDialog.dispose();
            }
            });
            final JCheckBox matchCheckBox=new JCheckBox("区分大小写(C)");
            ButtonGroup bGroup=new ButtonGroup();
            final JRadioButton upButton=new JRadioButton("向上(U)");
            final JRadioButton downButton=new JRadioButton("向下(U)");
            downButton.setSelected(true);
            bGroup.add(upButton);
            bGroup.add(downButton);
            /*ButtonGroup此类用于为一组按钮创建一个多斥（multiple-exclusion）作用域。
            使用相同的 ButtonGroup 对象创建一组按钮意味着“开启”其中一个按钮时，将关闭组中的其他所有按钮。*/
            /*JRadioButton此类实现一个单选按钮，此按钮项可被选择或取消选择，并可为用户显示其状态。
            与 ButtonGroup 对象配合使用可创建一组按钮，一次只能选择其中的一个按钮。
            （创建一个 ButtonGroup 对象并用其 add 方法将 JRadioButton 对象包含在此组中。）*/
             
            //"查找下一个"按钮监听
            findNextButton.addActionListener(new ActionListener()
            { public void actionPerformed(ActionEvent e)
            { //"区分大小写(C)"的JCheckBox是否被选中
            int k=0,m=0;
            final String str1,str2,str3,str4,strA,strB;
            str1=editArea.getText();
            str2=findText.getText();
            str3=str1.toUpperCase();
            str4=str2.toUpperCase();
            if(matchCheckBox.isSelected())//区分大小写
            { strA=str1;
             strB=str2;
            }
            else//不区分大小写,此时把所选内容全部化成大写(或小写)，以便于查找 
            { strA=str3;
             strB=str4;
            }
            if(upButton.isSelected())
            { 
             if(editArea.getSelectedText()==null)
             k=strA.lastIndexOf(strB,editArea.getCaretPosition()-1);
             else
             k=strA.lastIndexOf(strB, editArea.getCaretPosition()-findText.getText().length()-1); 
             if(k>-1)
             { 
             editArea.setCaretPosition(k);
             editArea.select(k,k+strB.length());
             }
             else
             { JOptionPane.showMessageDialog(null,"找不到您查找的内容！","查找",JOptionPane.INFORMATION_MESSAGE);
             }
            }
            else if(downButton.isSelected())
            { if(editArea.getSelectedText()==null)
             k=strA.indexOf(strB,editArea.getCaretPosition()+1);
             else
             k=strA.indexOf(strB, editArea.getCaretPosition()-findText.getText().length()+1); 
             if(k>-1)
             { //String strData=strA.subString(k,strB.getText().length()+1);
             editArea.setCaretPosition(k);
             editArea.select(k,k+strB.length());
             }
             else
             { JOptionPane.showMessageDialog(null,"找不到您查找的内容！","查找",JOptionPane.INFORMATION_MESSAGE);
             }
            }
            }
            });//"查找下一个"按钮监听结束
             
            //"替换"按钮监听
            replaceButton.addActionListener(new ActionListener()
            { public void actionPerformed(ActionEvent e)
            { 
                if(findText.getText().length()==0)
                { JOptionPane.showMessageDialog(replaceDialog,"请填写查找内容!","提示",JOptionPane.WARNING_MESSAGE);
                 findText.requestFocus(true);
                 return;
                }
            if(replaceText.getText().length()>0 && editArea.getSelectedText()!=null) 
             editArea.replaceSelection(replaceText.getText());//用给定的字符串替换当前选择的内容
            }
            });//"替换"按钮监听结束
             
            //"全部替换"按钮监听
            replaceAllButton.addActionListener(new ActionListener()
            { public void actionPerformed(ActionEvent e)
            { editArea.setCaretPosition(0); //将光标放到编辑区开头 
            int k=0,m=0,replaceCount=0;
            if(findText.getText().length()==0)
            { JOptionPane.showMessageDialog(replaceDialog,"请填写查找内容!","提示",JOptionPane.WARNING_MESSAGE);
             findText.requestFocus(true);
             return;
            }
            while(k>-1)//当文本中有内容被选中时(k>-1被选中)进行替换，否则不进行while循环
            { //"区分大小写(C)"的JCheckBox是否被选中
             //int k=0,m=0;
             final String str1,str2,str3,str4,strA,strB;
             str1=editArea.getText();
             str2=findText.getText();
             str3=str1.toUpperCase();
             str4=str2.toUpperCase();
             if(matchCheckBox.isSelected())//区分大小写
             { strA=str1;
             strB=str2;
             }
             else//不区分大小写,此时把所选内容全部化成大写(或小写)，以便于查找 
             { strA=str3;
             strB=str4;
             }
             if(upButton.isSelected())
             { //k=strA.lastIndexOf(strB,editArea.getCaretPosition()-1);
             if(editArea.getSelectedText()==null)
             k=strA.lastIndexOf(strB,editArea.getCaretPosition()-1);
             else
             k=strA.lastIndexOf(strB, editArea.getCaretPosition()-findText.getText().length()-1); 
             if(k>-1)
             { 
             editArea.setCaretPosition(k);
             editArea.select(k,k+strB.length());
             }
             else
             { if(replaceCount==0)
             { JOptionPane.showMessageDialog(replaceDialog, "找不到您查找的内容!", "记事本",JOptionPane.INFORMATION_MESSAGE); 
             }
             else
             { JOptionPane.showMessageDialog(replaceDialog,"成功替换"+replaceCount+"个匹配内容!","替换成功",JOptionPane.INFORMATION_MESSAGE);
             }
             }
             }
             else if(downButton.isSelected())
             { if(editArea.getSelectedText()==null)
             k=strA.indexOf(strB,editArea.getCaretPosition()+1);
             else
             k=strA.indexOf(strB, editArea.getCaretPosition()-findText.getText().length()+1); 
             if(k>-1)
             { 
             editArea.setCaretPosition(k);
             editArea.select(k,k+strB.length());
             }
             else
             { if(replaceCount==0)
             { JOptionPane.showMessageDialog(replaceDialog, "找不到您查找的内容!", "记事本",JOptionPane.INFORMATION_MESSAGE); 
             }
             else
             { JOptionPane.showMessageDialog(replaceDialog,"成功替换"+replaceCount+"个匹配内容!","替换成功",JOptionPane.INFORMATION_MESSAGE);
             }
             }
             }
             if(replaceText.getText().length()==0 && editArea.getSelectedText()!= null)
             { editArea.replaceSelection("");
             replaceCount++;
             } 
              
             if(replaceText.getText().length()>0 && editArea.getSelectedText()!= null) 
             { editArea.replaceSelection(replaceText.getText()); 
             replaceCount++;
             }
            }//while循环结束
            }
            });//"替换全部"方法结束
             
            //创建"替换"对话框的界面
            JPanel directionPanel=new JPanel();
            directionPanel.setBorder(BorderFactory.createTitledBorder("方向"));
            //设置directionPanel组件的边框;
            directionPanel.add(upButton);
            directionPanel.add(downButton);
            JPanel panel1=new JPanel();
            JPanel panel2=new JPanel();
            JPanel panel3=new JPanel();
            JPanel panel4=new JPanel();
            panel4.setLayout(new GridLayout(2,1));
            panel1.add(findContentLabel);
            panel1.add(findText);
            panel1.add(findNextButton);
            panel4.add(replaceButton);
            panel4.add(replaceAllButton);
            panel2.add(replaceLabel);
            panel2.add(replaceText);
            panel2.add(panel4);
            panel3.add(matchCheckBox);
            panel3.add(directionPanel);
            panel3.add(cancel);
            con.add(panel1);
            con.add(panel2);
            con.add(panel3);
            replaceDialog.setSize(420,220);
            replaceDialog.setResizable(false);//不可调整大小
            replaceDialog.setLocation(230,280);
            replaceDialog.setVisible(true);
        }
    }
    
    public void checkMenuItemEnabled()
     { String selectText=editArea.getSelectedText();
     if(selectText==null)
     { cut.setEnabled(false);
     popupMenu_Cut.setEnabled(false);
     copy.setEnabled(false);
     popupMenu_Copy.setEnabled(false);
    // delete.setEnabled(false);
     popupMenu_Delete.setEnabled(false);
     }
     else
     { cut.setEnabled(true);
     popupMenu_Cut.setEnabled(true); 
     copy.setEnabled(true);
     popupMenu_Copy.setEnabled(true);
     //editMenu_Delete.setEnabled(true);
     popupMenu_Delete.setEnabled(true);
     }
     //粘帖功能可用性判断
     Transferable contents=clipBoard.getContents(this);
     if(contents==null)
     { paste.setEnabled(false);
     popupMenu_Paste.setEnabled(false);
     }
     else
     { paste.setEnabled(true);
     popupMenu_Paste.setEnabled(true); 
     }
     }//方法checkMenuItemEnabled()结束
    @Override
    public void changedUpdate(DocumentEvent e) {
        // TODO Auto-generated method stub
        
    }
    @Override
    public void insertUpdate(DocumentEvent e) {
        // TODO Auto-generated method stub
        
    }
    @Override
    public void removeUpdate(DocumentEvent e) {
        // TODO Auto-generated method stub
        
    }
    
}