java记事本

import javax.swing.*;
import javax.swing.event.*;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.swing.text.BadLocationException;
import java.awt.*;
import java.awt.event.*;
import java.io.*;

public class NotepadApp extends JFrame {
    private JTextArea textArea; // 文本区域
    private JFileChooser fileChooser; // 文件选择器
    private File currentFile = null; // 当前文件
    private JTextArea lineNumbers; // 行号区域
    private JLabel positionLabel; // 显示当前位置（行、列）的标签
    private JLabel charCountLabel; // 显示字符数的标签
    private JLabel encodingLabel; // 显示编码格式的标签

    public NotepadApp() {
        setTitle("简易记事本");
        setSize(600, 400);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // 创建文本区域，自动换行
        textArea = new JTextArea();
        textArea.setFont(new Font("Monospaced", Font.PLAIN, 14));
        textArea.setLineWrap(true);  // 自动换行
        textArea.setWrapStyleWord(true); // 按单词换行

        // 创建行号显示区域
        lineNumbers = new JTextArea("1\n");
        lineNumbers.setFont(new Font("Monospaced", Font.PLAIN, 14));
        lineNumbers.setBackground(Color.LIGHT_GRAY);
        lineNumbers.setEditable(false);

        // 文本滚动面板
        JScrollPane scrollPane = new JScrollPane(textArea);
        scrollPane.setRowHeaderView(lineNumbers); // 左侧显示行号
        add(scrollPane, BorderLayout.CENTER);

        // 底部状态栏
        JPanel statusBar = new JPanel(new GridLayout(1, 3));
        positionLabel = new JLabel("行: 1, 列: 1");
        charCountLabel = new JLabel("字符数: 0");
        encodingLabel = new JLabel("编码: UTF-8");

        statusBar.add(positionLabel);
        statusBar.add(charCountLabel);
        statusBar.add(encodingLabel);
        add(statusBar, BorderLayout.SOUTH);

        // 创建菜单栏
        JMenuBar menuBar = new JMenuBar();
        JMenu fileMenu = new JMenu("文件");
        JMenu editMenu = new JMenu("编辑");
        JMenu formatMenu = new JMenu("格式");

        JMenuItem newItem = new JMenuItem("新建");
        JMenuItem openItem = new JMenuItem("打开");
        JMenuItem saveItem = new JMenuItem("保存");
        JMenuItem saveAsItem = new JMenuItem("另存为");
        JMenuItem exitItem = new JMenuItem("退出");

        JMenuItem findReplaceItem = new JMenuItem("查找/替换");
        JMenuItem fontItem = new JMenuItem("字体选择");

        fileMenu.add(newItem);
        fileMenu.add(openItem);
        fileMenu.add(saveItem);
        fileMenu.add(saveAsItem);
        fileMenu.addSeparator();
        fileMenu.add(exitItem);

        editMenu.add(findReplaceItem);
        formatMenu.add(fontItem);

        menuBar.add(fileMenu);
        menuBar.add(editMenu);
        menuBar.add(formatMenu);
        setJMenuBar(menuBar);

        // 右键菜单
        JPopupMenu popupMenu = new JPopupMenu();
        JMenuItem cutItem = new JMenuItem("剪切");
        JMenuItem copyItem = new JMenuItem("复制");
        JMenuItem pasteItem = new JMenuItem("粘贴");

        popupMenu.add(cutItem);
        popupMenu.add(copyItem);
        popupMenu.add(pasteItem);
        textArea.setComponentPopupMenu(popupMenu);

        // 文件选择器
        fileChooser = new JFileChooser();
        fileChooser.setFileFilter(new FileNameExtensionFilter("文本文件 (*.txt)", "txt"));

        // 事件监听
        newItem.addActionListener(e -> newFile());
        openItem.addActionListener(e -> openFile());
        saveItem.addActionListener(e -> saveFile());
        saveAsItem.addActionListener(e -> saveFileAs());
        exitItem.addActionListener(e -> System.exit(0));

        findReplaceItem.addActionListener(e -> showFindReplaceDialog());
        fontItem.addActionListener(e -> showFontDialog());

        cutItem.addActionListener(e -> textArea.cut());
        copyItem.addActionListener(e -> textArea.copy());
        pasteItem.addActionListener(e -> textArea.paste());

        // 监听文本变化，自动更新行号和字符数
        textArea.getDocument().addDocumentListener(new DocumentListener() {
            public void insertUpdate(DocumentEvent e) { updateStatusBar(); }
            public void removeUpdate(DocumentEvent e) { updateStatusBar(); }
            public void changedUpdate(DocumentEvent e) { updateStatusBar(); }
        });

        // 监听光标位置变化
        textArea.addCaretListener(e -> updateCursorPosition());

        setVisible(true);
    }
    private void showFontDialog() {
        String[] fonts = GraphicsEnvironment.getLocalGraphicsEnvironment().getAvailableFontFamilyNames();
        JComboBox<String> fontBox = new JComboBox<>(fonts);
        Integer[] sizes = {10, 12, 14, 16, 18, 20, 24, 28, 32, 36, 40};
        JComboBox<Integer> sizeBox = new JComboBox<>(sizes);
        JCheckBox boldBox = new JCheckBox("加粗");
        JCheckBox italicBox = new JCheckBox("斜体");

        JPanel panel = new JPanel();
        panel.setLayout(new GridLayout(4, 1));
        panel.add(fontBox);
        panel.add(sizeBox);
        panel.add(boldBox);
        panel.add(italicBox);

        int result = JOptionPane.showConfirmDialog(this, panel, "字体选择", JOptionPane.OK_CANCEL_OPTION);
        if (result == JOptionPane.OK_OPTION) {
            String fontName = (String) fontBox.getSelectedItem();
            int fontSize = (int) sizeBox.getSelectedItem();
            int fontStyle = Font.PLAIN;
            if (boldBox.isSelected()) fontStyle |= Font.BOLD;
            if (italicBox.isSelected()) fontStyle |= Font.ITALIC;
            textArea.setFont(new Font(fontName, fontStyle, fontSize));
        }
    }
    // 更新状态栏信息
    private void updateStatusBar() {
        // 获取当前文本内容
        String text = textArea.getText();
        int charCount = text.length();

        // 更新字符数
        charCountLabel.setText("字符数: " + charCount);

        // 更新编码（这里假设编码为 UTF-8）
        encodingLabel.setText("编码: UTF-8");
    }

    // 更新光标位置信息
    private void updateCursorPosition() {
        // 获取光标位置
        int caretPos = textArea.getCaretPosition();

        try {
            // 计算光标所在行和列
            int line = textArea.getLineOfOffset(caretPos) + 1; // 行从 1 开始
            int column = caretPos - textArea.getLineStartOffset(line - 1) + 1; // 列从 1 开始

            // 更新显示位置
            positionLabel.setText("行: " + line + ", 列: " + column);
        } catch (BadLocationException e) {
            e.printStackTrace();
        }
    }

    // 新建文件
    private void newFile() {
        textArea.setText("");
        currentFile = null;
        setTitle("新建 - 记事本");
        updateStatusBar();
    }

    // 打开文件
    private void openFile() {
        if (fileChooser.showOpenDialog(this) == JFileChooser.APPROVE_OPTION) {
            currentFile = fileChooser.getSelectedFile();
            try (BufferedReader reader = new BufferedReader(new FileReader(currentFile))) {
                textArea.read(reader, null);
                setTitle(currentFile.getName() + " - 记事本");
                updateStatusBar();
            } catch (IOException e) {
                JOptionPane.showMessageDialog(this, "无法打开文件", "错误", JOptionPane.ERROR_MESSAGE);
            }
        }
    }

    // 保存文件
    private void saveFile() {
        if (currentFile != null) {
            try (BufferedWriter writer = new BufferedWriter(new FileWriter(currentFile))) {
                textArea.write(writer);
            } catch (IOException e) {
                JOptionPane.showMessageDialog(this, "无法保存文件", "错误", JOptionPane.ERROR_MESSAGE);
            }
        } else {
            saveFileAs();
        }
    }

    // 另存为
    private void saveFileAs() {
        if (fileChooser.showSaveDialog(this) == JFileChooser.APPROVE_OPTION) {
            currentFile = fileChooser.getSelectedFile();
            if (!currentFile.getName().toLowerCase().endsWith(".txt")) {
                currentFile = new File(currentFile.getAbsolutePath() + ".txt");
            }
            saveFile();
            setTitle(currentFile.getName() + " - 记事本");
        }
    }

    // 查找和替换
    private void showFindReplaceDialog() {
        JDialog dialog = new JDialog(this, "查找/替换", true);
        dialog.setSize(400, 150);
        dialog.setLayout(new GridLayout(3, 2));

        JLabel findLabel = new JLabel("查找:");
        JTextField findField = new JTextField();
        JLabel replaceLabel = new JLabel("替换:");
        JTextField replaceField = new JTextField();
        JButton findButton = new JButton("查找");
        JButton replaceButton = new JButton("替换");

        dialog.add(findLabel);
        dialog.add(findField);
        dialog.add(replaceLabel);
        dialog.add(replaceField);
        dialog.add(findButton);
        dialog.add(replaceButton);

        findButton.addActionListener(e -> {
            String findText = findField.getText();
            String content = textArea.getText();
            int index = content.indexOf(findText);
            if (index != -1) {
                textArea.setCaretPosition(index);
                textArea.select(index, index + findText.length());
            } else {
                JOptionPane.showMessageDialog(dialog, "未找到文本", "提示", JOptionPane.INFORMATION_MESSAGE);
            }
        });

        replaceButton.addActionListener(e -> {
            String findText = findField.getText();
            String replaceText = replaceField.getText();
            textArea.setText(textArea.getText().replace(findText, replaceText));
        });

        dialog.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(NotepadApp::new);
    }
}