Java简易记事本

好的，下面是一个Java简易记事本的示例代码，包含基本功能如新建、打开、保存、剪切、复制、粘贴、查找、替换、字体和颜色设置等。

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;

public class SimpleNotepad extends JFrame {
    private JTextArea textArea;
    private JFileChooser fileChooser;
    private String currentFilename;

    public SimpleNotepad() {
        setTitle("Simple Notepad");
        setSize(400, 400);
        setLocationRelativeTo(null);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        textArea = new JTextArea();
        JScrollPane scrollPane = new JScrollPane(textArea);
        add(scrollPane, BorderLayout.CENTER);

        fileChooser = new JFileChooser();

        JMenuBar menuBar = new JMenuBar();
        setJMenuBar(menuBar);

        JMenu fileMenu = new JMenu("File");
        menuBar.add(fileMenu);

        JMenuItem newMenuItem = new JMenuItem("New");
        newMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                newFile();
            }
        });
        fileMenu.add(newMenuItem);

        JMenuItem openMenuItem = new JMenuItem("Open");
        openMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                openFile();
            }
        });
        fileMenu.add(openMenuItem);

        JMenuItem saveMenuItem = new JMenuItem("Save");
        saveMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                saveFile();
            }
        });
        fileMenu.add(saveMenuItem);

        JMenuItem saveAsMenuItem = new JMenuItem("Save As...");
        saveAsMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                saveFileAs();
            }
        });
        fileMenu.add(saveAsMenuItem);

        fileMenu.addSeparator();

        JMenuItem exitMenuItem = new JMenuItem("Exit");
        exitMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                System.exit(0);
            }
        });
        fileMenu.add(exitMenuItem);

        JMenu editMenu = new JMenu("Edit");
        menuBar.add(editMenu);

        JMenuItem cutMenuItem = new JMenuItem("Cut");
        cutMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textArea.cut();
            }
        });
        editMenu.add(cutMenuItem);

        JMenuItem copyMenuItem = new JMenuItem("Copy");
        copyMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textArea.copy();
            }
        });
        editMenu.add(copyMenuItem);

        JMenuItem pasteMenuItem = new JMenuItem("Paste");
        pasteMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                textArea.paste();
            }
        });
        editMenu.add(pasteMenuItem);

        editMenu.addSeparator();

        JMenuItem findMenuItem = new JMenuItem("Find");
        findMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String searchText = JOptionPane.showInputDialog(SimpleNotepad.this, "Find:");
                if (searchText != null) {
                    String text = textArea.getText();
                    int index = text.indexOf(searchText);
                    if (index != -1) {
                        textArea.setSelectionStart(index);
                        textArea.setSelectionEnd(index + searchText.length());
                        textArea.requestFocusInWindow();
                    }
                }
            }
        });
        editMenu.add(findMenuItem);

        JMenuItem replaceMenuItem = new JMenuItem("Replace");
        replaceMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                String searchText = JOptionPane.showInputDialog(SimpleNotepad.this, "Find:");
                if (searchText != null) {
                    String replaceText = JOptionPane.showInputDialog(SimpleNotepad.this, "Replace with:");
                    if (replaceText != null) {
                        String text = textArea.getText();
                        String newText = text.replace(searchText, replaceText);
                        textArea.setText(newText);
                    }
                }
            }
        });
        editMenu.add(replaceMenuItem);

        JMenu formatMenu = new JMenu("Format");
        menuBar.add(formatMenu);

        JMenuItem fontMenuItem = new JMenuItem("Font...");
        fontMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                Font font = textArea.getFont();
                JFontChooser fontChooser = new JFontChooser(SimpleNotepad.this, font);
                if (fontChooser.showDialog() == JFontChooser.OK_OPTION) {
                    Font newFont = fontChooser.getSelectedFont();
                    textArea.setFont(newFont);
                }
            }
        });
        formatMenu.add(fontMenuItem);

        JMenuItem colorMenuItem = new JMenuItem("Color...");
        colorMenuItem.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                Color color = textArea.getForeground();
                Color newColor = JColorChooser.showDialog(SimpleNotepad.this, "Choose Color", color);
                if (newColor != null) {
                    textArea.setForeground(newColor);
                }
            }
        });
        formatMenu.add(colorMenuItem);
    }

    private void newFile() {
        textArea.setText("");
        currentFilename = null;
        setTitle("Simple Notepad");
    }

    private void openFile() {
        if (fileChooser.showOpenDialog(this) == JFileChooser.APPROVE_OPTION) {
            File file = fileChooser.getSelectedFile();
            try {
                BufferedReader reader