java记事本图形界面

以下是一个简单的 Java 记事本图形界面的示例代码：

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

public class JavaNotepad extends JFrame implements ActionListener {

    JTextArea textArea = new JTextArea();
    JScrollPane scrollPane = new JScrollPane(textArea);
    JMenuBar menuBar = new JMenuBar();
    JMenu fileMenu = new JMenu("File");
    JMenuItem newMenuItem = new JMenuItem("New");
    JMenuItem openMenuItem = new JMenuItem("Open");
    JMenuItem saveMenuItem = new JMenuItem("Save");
    JMenuItem exitMenuItem = new JMenuItem("Exit");

    public JavaNotepad() {
        setTitle("Java Notepad");
        setSize(500, 500);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLocationRelativeTo(null);

        fileMenu.add(newMenuItem);
        fileMenu.add(openMenuItem);
        fileMenu.add(saveMenuItem);
        fileMenu.add(exitMenuItem);
        menuBar.add(fileMenu);
        setJMenuBar(menuBar);

        add(scrollPane);

        newMenuItem.addActionListener(this);
        openMenuItem.addActionListener(this);
        saveMenuItem.addActionListener(this);
        exitMenuItem.addActionListener(this);
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == newMenuItem) {
            textArea.setText("");
        } else if (e.getSource() == openMenuItem) {
            JFileChooser fileChooser = new JFileChooser();
            int result = fileChooser.showOpenDialog(this);
            if (result == JFileChooser.APPROVE_OPTION) {
                File file = fileChooser.getSelectedFile();
                try {
                    FileReader reader = new FileReader(file);
                    BufferedReader bufferedReader = new BufferedReader(reader);
                    textArea.read(bufferedReader, null);
                    bufferedReader.close();
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        } else if (e.getSource() == saveMenuItem) {
            JFileChooser fileChooser = new JFileChooser();
            int result = fileChooser.showSaveDialog(this);
            if (result == JFileChooser.APPROVE_OPTION) {
                File file = fileChooser.getSelectedFile();
                try {
                    FileWriter writer = new FileWriter(file);
                    BufferedWriter bufferedWriter = new BufferedWriter(writer);
                    textArea.write(bufferedWriter);
                    bufferedWriter.close();
                } catch (Exception ex) {
                    ex.printStackTrace();
                }
            }
        } else if (e.getSource() == exitMenuItem) {
            System.exit(0);
        }
    }

    public static void main(String[] args) {
        JavaNotepad notepad = new JavaNotepad();
        notepad.setVisible(true);
    }
}

运行该代码将会打开一个简单的记事本窗口，其中包含菜单栏和一个文本区域。用户可以使用菜单栏上的选项来新建、打开、保存或退出文档。文本区域支持复制、粘贴和撤销等基本文本编辑功能。