急求,JAVA语言高手帮我解难

Question

今天朋友给了我一个简单的JAVA 应用程序
本人网络方向,有些地方不是太懂
   希望大家帮我解释一下
   帮我写下每一段或句字的解释代码如下:是一个记事本的代码希望高手可以粘贴过后,帮我每行注释
import javax.swing.*; 
import javax.swing.event.*; 
import java.awt.*; 
import java.awt.event.*; 
import java.io.*; 
import java.awt.color.*; 
import java.awt.font.*; 
import javax.swing.undo.*; public class Note extends JFrame 
{ 
boolean isChange=false; 
boolean wasChange=false; 
JMenuBar menuBar=new JMenuBar(); JMenu menuFile=new JMenu("File"); 
JMenuItem menuFileOpen=new JMenuItem("Open.."); 
JMenuItem menuFileSave=new JMenuItem("Save.."); 
JMenuItem menuFileExit=new JMenuItem("Exit"); JMenu menuEdit=new JMenu("Edit"); 
JMenuItem menuFileCut=new JMenuItem("Cut"); 
JMenuItem font=new JMenuItem("Font"); 
JMenuItem menuFilePaste=new JMenuItem("Paste"); JTextArea fileArea=new JTextArea(); public Note() 
{ 
this.setTitle("记事本"); 
Toolkit tool=this.getToolkit();//窗口图标！ 
Image myimage=tool.getImage("戒指.jpg"); 
this.setIconImage(myimage); 
setDefaultCloseOperation(DO_NOTHING_ON_CLOSE); 
addWindowListener(new WindowAdapter() 
{ 
public void windowClosing(WindowEvent e) 
{ 
exit(); 
} 
}); 
menuFileOpen.addActionListener(new ActionListener() 
{ 
public void actionPerformed(ActionEvent e) 
{ 
fileOpen_actionPerformed(e); 
} 
}); 
menuFileSave.addActionListener(new ActionListener() 
{ 
public void actionPerformed(ActionEvent e) 
{ 
fileSave_actionPerformed(e); 
} 
}); 
menuFileExit.addActionListener(new ActionListener() 
{ 
public void actionPerformed(ActionEvent e) 
{ 
fileExit_actionPerformed(e); 
} 
}); 
menuFileCut.addActionListener(new ActionListener() 
{ 
public void actionPerformed(ActionEvent e) 
{ 
fileCut_actionPerformed(e); 
} 
}); 
menuFilePaste.addActionListener(new ActionListener() 
{ 
public void actionPerformed(ActionEvent e) 
{ 
filePaste_actionPerformed(e); 
} 
}); 
font.addActionListener(new ActionListener () 
{ 
public void actionPerformed(ActionEvent e) 
{ 
fileColor_actionPerformed(e); 
} 
}); 
fileArea.getDocument().addDocumentListener(new DocumentListener() 
{ 
public void insertUpdate(DocumentEvent e) 
{ 
wasChange=isChange; 
isChange=true; 
} 
public void removeUpdate(DocumentEvent e) 
{ 
wasChange=isChange; 
isChange=true; 
} 
public void changedUpdate(DocumentEvent e) 
{ 
wasChange=isChange; 
isChange=true; 
} 
}); 
setSize(500,450); 
menuBar.add(menuFile); 
menuFile.setMnemonic('F'); 
menuBar.add(menuEdit); 
menuEdit.setMnemonic('E'); 
menuFile.add(menuFileOpen); 
menuFileOpen.setMnemonic('O');//访问健; 
menuFileOpen.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O,InputEvent.CTRL_MASK));//快捷健; 
menuFile.add(menuFileSave); 
menuFileSave.setMnemonic('S'); 
menuFileSave.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S,InputEvent.CTRL_MASK)); 
menuFile.addSeparator(); 
menuFile.add(menuFileExit); 
menuFileExit.setMnemonic('E'); 
menuEdit.add(menuFileCut); 
menuFileCut.setMnemonic('C'); 
menuFileCut.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C,InputEvent.CTRL_MASK)); 
menuEdit.add(menuFilePaste); 
menuFilePaste.setMnemonic('P'); 
menuFilePaste.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_P,InputEvent.CTRL_MASK)); 
menuEdit.add(font); 
font.setMnemonic('N'); 
font.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_N,InputEvent.CTRL_MASK)); 
this.getContentPane().add(new JScrollPane(fileArea)); 
setJMenuBar(menuBar); 
fileArea.setLineWrap(true); 
} 
public void fileExit_actionPerformed(ActionEvent e) 
{ 
System.exit(0); 
} 
public void fileOpen_actionPerformed(ActionEvent e) 
{ 
//以下是filter; 
JFileChooser fileChooser=new JFileChooser(); 
//fileChooser.addChoosableFileFilter(new myFilter("*.txt","Files(*.txt)")); 
fileChooser.addChoosableFileFilter(fileChooser.getFileFilter()); 
if(fileChooser.APPROVE_OPTION!=fileChooser.showOpenDialog(this))return; 
//以下是文件读 
BufferedReader dataIn=null; 
try 
{ 
dataIn=new BufferedReader(new FileReader(fileChooser.getSelectedFile().getPath())); 
String c=null; 
do 
{ 
c=dataIn.readLine(); 
if(c!=null) 
fileArea.append(c+"\n"); 
} 
while(c!=null); 
} 
catch(Exception ex) 
{ 
System.out.println("Catch exception:"+ex.toString()); 
} 
} 
public void exit() 
{ 
if(isChange==false) 
System.exit(1); 
else 
{ 
int decision=JOptionPane.showConfirmDialog(this,"The File has Change.\n"+"Do you want to save the change?", 
"Notepad",JOptionPane.YES_NO_CANCEL_OPTION,JOptionPane.WARNING_MESSAGE); 
if (decision == JOptionPane.YES_OPTION) 
{ 
//以下是将文件写入计算机! 
try { 
JFileChooser fileSave = new JFileChooser(); 
fileSave.setDialogTitle("保存文件"); 
//fileSave.addChoosableFileFilter(new myFilter("*.txt","Files(*.txt)")); 
fileSave.addChoosableFileFilter(fileSave.getFileFilter()); 
if (fileSave.APPROVE_OPTION != fileSave.showSaveDialog(this)) 
return; 
BufferedWriter dataOut = new BufferedWriter(new BufferedWriter(new 
FileWriter(fileSave.getSelectedFile()))); 
String c = null; 
do { 
String str = fileArea.getText(); 
dataOut.write(str); 
dataOut.close(); 
} 
while (c != null); 
} 
catch (Exception e2) { 
System.out.println("Catch exception:有错误!" + e2.toString()); 
} 
} 
else if (decision == JOptionPane.NO_OPTION) 
System.exit(1); 
else if (decision == JOptionPane.CANCEL_OPTION); 
; 
} 
//innerclass.fileSave_actionPerformed(); 
} 
public void fileSave_actionPerformed(ActionEvent e1) 
{ //以下是将文件写入计算机! 
try 
{ 
JFileChooser fileSave=new JFileChooser(); 
fileSave.setDialogTitle("保存文件" ); 
//fileSave.addChoosableFileFilter(new myFilter("*.txt","Files(*.txt)")); 
fileSave.addChoosableFileFilter(fileSave.getFileFilter()); 
if(fileSave.APPROVE_OPTION!=fileSave.showSaveDialog(this))return; 
BufferedWriter dataOut=new BufferedWriter(new BufferedWriter(new FileWriter(fileSave.getSelectedFile()+".txt"))); 
//RandomAccessFile dataOut=new RandomAccessFile(fileSave.getSelectedFile(),"rw"); 
String c=null; 
do 
{ 
String str=fileArea.getText(); 
dataOut.write(str); 
dataOut.close(); 
} 
while(c!=null); 
} 
catch(Exception e2) 
{ 
System.out.println("Catch exception:有错误!"+e2.toString()); 
} 
} 
public static void main(String arg[]) 
{ 
Note nt=new Note(); 
nt.show(); 
} 
public void fileCut_actionPerformed(ActionEvent e) 
{ 
fileArea.cut(); 
} 
public void filePaste_actionPerformed(ActionEvent e) 
{ 
fileArea.paste(); 
} 
public void fileColor_actionPerformed(ActionEvent e) 
{ 
JColorChooser fileColor=new JColorChooser(); 
//fileArea.setForeground(fileColor.showDialog(this,"颜色",Color.red)); 
//fileArea.setSelectionColor(fileColor.showDialog(this,"颜色",Color.red)); 
fileArea.setSelectionColor(fileColor.showDialog(this,"颜色",Color.black)); 
} 
} 

Answer 1

package infant.query;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.awt.color.*;
import java.awt.font.*;
import javax.swing.undo.*;/**
 * <p>Title: </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2007</p>
 *
 * <p>Company: </p>
 *
 * @author not attributable
 * @version 1.0
 */public class Note extends JFrame {
    boolean isChange = false;
    boolean wasChange = false;
    JMenuBar menuBar = new JMenuBar();//实例菜单栏    JMenu menuFile = new JMenu("File");//实例"File"菜单
    JMenuItem menuFileOpen = new JMenuItem("Open..");//实例“File”菜单下的“Open..”选项
    JMenuItem menuFileSave = new JMenuItem("Save..");
    JMenuItem menuFileExit = new JMenuItem("Exit");    JMenu menuEdit = new JMenu("Edit");
    JMenuItem menuFileCut = new JMenuItem("Cut");
    JMenuItem font = new JMenuItem("Font");
    JMenuItem menuFilePaste = new JMenuItem("Paste");    JTextArea fileArea = new JTextArea();    public Note() {
        this.setTitle("记事本");
        Toolkit tool = this.getToolkit(); //窗口图标！
        Image myimage = tool.getImage("戒指.jpg");
        this.setIconImage(myimage);
        setDefaultCloseOperation(DO_NOTHING_ON_CLOSE);//设置用户在此窗体上发起 "close" 时默认执行的操作。“DO_NOTHING_ON_CLOSE”是指关闭的时候什么都不做
        addWindowListener(new WindowAdapter() {//添加指定的窗口侦听器
            public void windowClosing(WindowEvent e) {
                exit();
            }
        });
        menuFileOpen.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                fileOpen_actionPerformed(e);
            }
        });
        menuFileSave.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                fileSave_actionPerformed(e);
            }
        });
        menuFileExit.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                fileExit_actionPerformed(e);
            }
        });
        menuFileCut.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                fileCut_actionPerformed(e);
            }
        });
        menuFilePaste.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                filePaste_actionPerformed(e);
            }
        });
        font.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                fileColor_actionPerformed(e);
            }
        });
        fileArea.getDocument().addDocumentListener(new DocumentListener() {
            public void insertUpdate(DocumentEvent e) {
                wasChange = isChange;
                isChange = true;
            }            public void removeUpdate(DocumentEvent e) {
                wasChange = isChange;
                isChange = true;
            }            public void changedUpdate(DocumentEvent e) {
                wasChange = isChange;
                isChange = true;
            }
        });
        setSize(500, 450);//设置窗体大小
        menuBar.add(menuFile);
        menuFile.setMnemonic('F');
        menuBar.add(menuEdit);
        menuEdit.setMnemonic('E');
        menuFile.add(menuFileOpen);
        menuFileOpen.setMnemonic('O'); //访问健;
        menuFileOpen.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O,
                InputEvent.CTRL_MASK)); //快捷健;
        menuFile.add(menuFileSave);
        menuFileSave.setMnemonic('S');//设置当前模型上的键盘助记符，不过现在setMnemonic(char mnemonic)方法已废弃,应使用setMnemonic(int mnemonic) 
        menuFileSave.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S,
                InputEvent.CTRL_MASK));
        menuFile.addSeparator();
        menuFile.add(menuFileExit);
        menuFileExit.setMnemonic('E');
        menuEdit.add(menuFileCut);
        menuFileCut.setMnemonic('C');
        menuFileCut.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_C,
                InputEvent.CTRL_MASK));
        menuEdit.add(menuFilePaste);
        menuFilePaste.setMnemonic('P');
        menuFilePaste.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_P,
                InputEvent.CTRL_MASK));
        menuEdit.add(font);
        font.setMnemonic('N');
        font.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_N,
                InputEvent.CTRL_MASK));
        this.getContentPane().add(new JScrollPane(fileArea));
        setJMenuBar(menuBar);
        fileArea.setLineWrap(true);
    }    public void fileExit_actionPerformed(ActionEvent e) {//“fileExit”选项监听器
        System.exit(0);//执行退出操作
    }    public void fileOpen_actionPerformed(ActionEvent e) {//“fileOpen”选项监听器
//以下是filter;
        JFileChooser fileChooser = new JFileChooser();//目录文件选择器
//fileChooser.addChoosableFileFilter(new   myFilter("*.txt","Files(*.txt)"));
        fileChooser.addChoosableFileFilter(fileChooser.getFileFilter());
        if (fileChooser.APPROVE_OPTION != fileChooser.showOpenDialog(this))//“fileChooser.APPROVE_OPTION”:选择确认（yes、ok）后返回该值。
            return;
//以下是文件读
        BufferedReader dataIn = null;//“BufferedReader”：从字符输入流中读取文本
        try {
            dataIn = new BufferedReader(new FileReader(fileChooser.
                    getSelectedFile().getPath()));
            String c = null;
            do {
                c = dataIn.readLine();//读取一个文本行
                if (c != null)
                    fileArea.append(c + "\n");//将给定文本追加到文档结尾,此处为“换行”
            } while (c != null);
        } catch (Exception ex) {
            System.out.println("Catch   exception:" + ex.toString());
        }
    }    public void exit() {
        if (isChange == false)
            System.exit(1);
        else {
            int decision = JOptionPane.showConfirmDialog(this,//退出时如果未执行保存操作则提示
                    "The   File   has   Change.\n" +
                    "Do   you   want   to   save   the   change?",
                        "Notepad", JOptionPane.YES_NO_CANCEL_OPTION,
                        JOptionPane.WARNING_MESSAGE);//拥有“是”“否”“撤销”类型的提示框
            if (decision == JOptionPane.YES_OPTION) {//选择“是”的情况
//以下是将文件写入计算机!
                try {
                    JFileChooser fileSave = new JFileChooser();
                    fileSave.setDialogTitle("保存文件");
//fileSave.addChoosableFileFilter(new   myFilter("*.txt","Files(*.txt)"));
                    fileSave.addChoosableFileFilter(fileSave.getFileFilter());
                    if (fileSave.APPROVE_OPTION != fileSave.showSaveDialog(this))
                        return;
                    BufferedWriter dataOut = new BufferedWriter(new
                            BufferedWriter(new
                                           FileWriter(fileSave.getSelectedFile())));//“BufferedWriter”：将文本写入字符输出流
                    String c = null;
                    do {
                        String str = fileArea.getText();
                        dataOut.write(str);
                        dataOut.close();
                    } while (c != null);
                } catch (Exception e2) {
                    System.out.println("Catch   exception:有错误!" + e2.toString());
                }
            } else if (decision == JOptionPane.NO_OPTION)//选择“否”的情况
                System.exit(1);
            else if (decision == JOptionPane.CANCEL_OPTION)//选择“取消”的情况
                ;
                ;
        }
//innerclass.fileSave_actionPerformed();
    }    /***********************/
}

Answer 2

 public void fileSave_actionPerformed(ActionEvent e1) {//以下是将文件写入计算机!
        try {
            JFileChooser fileSave = new JFileChooser();
            fileSave.setDialogTitle("保存文件");
//fileSave.addChoosableFileFilter(new   myFilter("*.txt","Files(*.txt)"));
            fileSave.addChoosableFileFilter(fileSave.getFileFilter());
            if (fileSave.APPROVE_OPTION != fileSave.showSaveDialog(this))
                return;
            BufferedWriter dataOut = new BufferedWriter(new BufferedWriter(new
                    FileWriter(fileSave.getSelectedFile() + ".txt")));
//RandomAccessFile   dataOut=new   RandomAccessFile(fileSave.getSelectedFile(),"rw");
            String c = null;
            do {
                String str = fileArea.getText();
                dataOut.write(str);
                dataOut.close();
            } while (c != null);
        } catch (Exception e2) {
            System.out.println("Catch   exception:有错误!" + e2.toString());
        }
    }    public static void main(String arg[]) {
        Note nt = new Note();
        nt.show();
    }    public void fileCut_actionPerformed(ActionEvent e) {
        fileArea.cut();
    }    public void filePaste_actionPerformed(ActionEvent e) {
        fileArea.paste();
    }    public void fileColor_actionPerformed(ActionEvent e) {
        JColorChooser fileColor = new JColorChooser();
//fileArea.setForeground(fileColor.showDialog(this,"颜色",Color.red));
//fileArea.setSelectionColor(fileColor.showDialog(this,"颜色",Color.red));
        fileArea.setSelectionColor(fileColor.showDialog(this, "颜色", Color.black));
    }