使用Java设计一个简单的文本编辑器，实现类似Windows的记事本打的简单功能， 具有菜单、工具栏和状态栏。要求对每段代码注释

好的，以下是代码实现：

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JColorChooser;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenuBar;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JToolBar;
import javax.swing.filechooser.FileNameExtensionFilter;

/**
 * A simple text editor implemented in Java using Swing
 * 
 * @author [Your Name]
 *
 */
public class TextEditor extends JFrame implements ActionListener {

    private static final long serialVersionUID = 1L;

    private JTextArea textArea;
    private JLabel statusBar;
    private String fileName;
    private boolean saved;

    /**
     * Constructor for TextEditor class
     */
    public TextEditor() {
        super("Text Editor");

        // Setting up menu bar
        JMenuBar menuBar = new JMenuBar();
        setJMenuBar(menuBar);

        // Setting up file menu
        JMenu fileMenu = new JMenu("File");
        menuBar.add(fileMenu);

        // Adding menu items to file menu
        JMenuItem newMenuItem = new JMenuItem("New");
        newMenuItem.addActionListener(this);
        fileMenu.add(newMenuItem);

        JMenuItem openMenuItem = new JMenuItem("Open");
        openMenuItem.addActionListener(this);
        fileMenu.add(openMenuItem);

        JMenuItem saveMenuItem = new JMenuItem("Save");
        saveMenuItem.addActionListener(this);
        fileMenu.add(saveMenuItem);

        JMenuItem saveAsMenuItem = new JMenuItem("Save As");
        saveAsMenuItem.addActionListener(this);
        fileMenu.add(saveAsMenuItem);

        JMenuItem exitMenuItem = new JMenuItem("Exit");
        exitMenuItem.addActionListener(this);
        fileMenu.add(exitMenuItem);

        // Setting up edit menu
        JMenu editMenu = new JMenu("Edit");
        menuBar.add(editMenu);

        // Adding menu items to edit menu
        JMenuItem cutMenuItem = new JMenuItem("Cut");
        cutMenuItem.addActionListener(this);
        editMenu.add(cutMenuItem);

        JMenuItem copyMenuItem = new JMenuItem("Copy");
        copyMenuItem.addActionListener(this);
        editMenu.add(copyMenuItem);

        JMenuItem pasteMenuItem = new JMenuItem("Paste");
        pasteMenuItem.addActionListener(this);
        editMenu.add(pasteMenuItem);

        // Setting up toolbar
        JToolBar toolBar = new JToolBar();
        add(toolBar, BorderLayout.PAGE_START);

        // Adding buttons to toolbar
        ImageIcon newIcon = new ImageIcon("icons/new.png");
        JButton newButton = new JButton(newIcon);
        newButton.addActionListener(this);
        toolBar.add(newButton);

        ImageIcon openIcon = new ImageIcon("icons/open.png");
        JButton openButton = new JButton(openIcon);
        openButton.addActionListener(this);
        toolBar.add(openButton);

        ImageIcon saveIcon = new ImageIcon("icons/save.png");
        JButton saveButton = new JButton(saveIcon);
        saveButton.addActionListener(this);
        toolBar.add(saveButton);

        ImageIcon cutIcon = new ImageIcon("icons/cut.png");
        JButton cutButton = new JButton(cutIcon);
        cutButton.addActionListener(this);
        toolBar.add(cutButton);

        ImageIcon copyIcon = new ImageIcon("icons/copy.png");
        JButton copyButton = new JButton(copyIcon);
        copyButton.addActionListener(this);
        toolBar.add(copyButton);

        ImageIcon pasteIcon = new ImageIcon("icons/paste.png");
        JButton pasteButton = new JButton(pasteIcon);
        pasteButton.addActionListener(this);
        toolBar.add(pasteButton);

        // Setting up text area
        textArea = new JTextArea();
        textArea.setFont(new Font("Arial", Font.PLAIN, 20));
        textArea.setBorder(BorderFactory.createLineBorder(Color.BLACK));
        JScrollPane scrollPane = new JScrollPane(textArea);
        add(scrollPane, BorderLayout.CENTER);

        // Setting up status bar
        statusBar = new JLabel("Ready");
        add(statusBar, BorderLayout.SOUTH);

        // Setting up frame
        setSize(800, 600);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setVisible(true);

        // Initializing fields
        fileName = "Untitled";
        saved = true;
    }

    /**
     * Main method for TextEditor class
     * 
     * @param args
     */
    public static void main(String[] args) {
        new TextEditor();
    }

    /**
     * Method to handle actionPerformed events
     */
    public void actionPerformed(ActionEvent e) {
        String command = e.getActionCommand();

        switch (command) {
        case "New":
            newFile();
            break;
        case "Open":
            openFile();
            break;
        case "Save":
            saveFile();
            break;
        case "Save As":
            saveFileAs();
            break;
        case "Exit":
            exit();
            break;
        case "Cut":
            textArea.cut();
            break;
        case "Copy":
            textArea.copy();
            break;
        case "Paste":
            textArea.paste();
            break;
        }
    }

    /**
     * Method to create a new file
     */
    private void newFile() {
        if (!saved) {
            int option = JOptionPane.showConfirmDialog(this, "Do you want to save changes to " + fileName + "?",
                    "Save Changes", JOptionPane.YES_NO_CANCEL_OPTION);
            if (option == JOptionPane.YES_OPTION) {
                saveFile();
            } else if (option == JOptionPane.CANCEL_OPTION) {
                return;
            }
        }

        textArea.setText("");
        fileName = "Untitled";
        saved = true;
        statusBar.setText("New file created");
    }

    /**
     * Method to open a file
     */
    private void openFile() {
        if (!saved) {
            int option = JOptionPane.showConfirmDialog(this, "Do you want to save changes to " + fileName + "?",
                    "Save Changes", JOptionPane.YES_NO_CANCEL_OPTION);
            if (option == JOptionPane.YES_OPTION) {
                saveFile();
            } else if (option == JOptionPane.CANCEL_OPTION) {
                return;
            }
        }

        JFileChooser fileChooser = new JFileChooser();
        FileNameExtensionFilter filter = new FileNameExtensionFilter("Text Files", "txt");
        fileChooser.setFileFilter(filter);
        int option = fileChooser.showOpenDialog(this);
        if (option == JFileChooser.APPROVE_OPTION) {
            File file = fileChooser.getSelectedFile();
            fileName = file.getName();
            try {
                BufferedReader reader = new BufferedReader(new FileReader(file));
                String line;
                StringBuilder sb = new StringBuilder();
                while ((line = reader.readLine()) != null) {
                    sb.append(line).append("\n");
                }
                reader.close();
                textArea.setText(sb.toString());
                saved = true;
                statusBar.setText("File opened: " + fileName);
            } catch (IOException e) {
                JOptionPane.showMessageDialog(this, "Error: " + e.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
            }
        }
    }

    /**
     * Method to save a file
     */
    private void saveFile() {
        if (saved) {
            return;
        }

        if (fileName.equals("Untitled")) {
            saveFileAs();
        } else {
            try {
                BufferedWriter writer = new BufferedWriter(new FileWriter(fileName));
                writer.write(textArea.getText());
                writer.close();
                saved = true;
                statusBar.setText("File saved: " + fileName);
            } catch (IOException e) {
                JOptionPane.showMessageDialog(this, "Error: " + e.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
            }
        }
    }

    /**
     * Method to save a file with a new name
     */
    private void saveFileAs() {
        JFileChooser fileChooser = new JFileChooser();
        FileNameExtensionFilter filter = new FileNameExtensionFilter("Text Files", "txt");
        fileChooser.setFileFilter(filter);
        int option = fileChooser.showSaveDialog(this);
        if (option == JFileChooser.APPROVE_OPTION) {
            File file = fileChooser.getSelectedFile();
            fileName = file.getName();
            if (!fileName.endsWith(".txt")) {
                fileName += ".txt";
            }
            try {
                BufferedWriter writer = new BufferedWriter(new FileWriter(file));
                writer.write(textArea.getText());
                writer.close();
                saved = true;
                statusBar.setText("File saved: " + fileName);
            } catch (IOException e) {
                JOptionPane.showMessageDialog(this, "Error: " + e.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
            }
        }
    }

    /**
     * Method to exit the program
     */
    private void exit() {
        if (!saved) {
            int option = JOptionPane.showConfirmDialog(this, "Do you want to save changes to " + fileName + "?",
                    "Save Changes", JOptionPane.YES_NO_CANCEL_OPTION);
            if (option == JOptionPane.YES_OPTION) {
                saveFile();
            } else if (option == JOptionPane.CANCEL_OPTION) {
                return;
            }
        }

        System.exit(0);
    }
}

此代码实现了一个简单的文本编辑器，具有菜单、工具栏和状态栏。可以打开、编辑、保存和另存为文本文件。还可以剪切、复制和粘贴文本。状态栏显示文件的状态，以及操作的结果。