java简易记事本代码

Java简易记事本代码通常是一个基础的控制台应用，它允许用户创建、编辑和查看文本文件。以下是一个简单的例子，使用Java Swing库来创建一个基本的界面：

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

public class SimpleNotePad {
    private JTextArea textArea;
    private JButton btnSave, btnCancel, btnLoad;

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    SimpleNotePad window = new SimpleNotePad();
                    window.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public SimpleNotePad() throws IOException {
        JFrame frame = new JFrame("Simple Note Pad");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(400, 300);
        frame.setLayout(new BorderLayout());

        textArea = new JTextArea();
        textArea.setEditable(true);
        JScrollPane scrollPane = new JScrollPane(textArea);

        JPanel buttonPanel = new JPanel();
        btnSave = new JButton("Save");
        btnCancel = new JButton("Cancel");
        btnLoad = new JButton("Load");

        btnSave.addActionListener(e -> saveToFile());
        btnCancel.addActionListener(e -> close());
        btnLoad.addActionListener(e -> loadFromFile());

        buttonPanel.add(btnSave);
        buttonPanel.add(btnCancel);
        buttonPanel.add(btnLoad);

        frame.add(scrollPane, BorderLayout.CENTER);
        frame.add(buttonPanel, BorderLayout.SOUTH);
    }

    private void saveToFile() {
        JFileChooser chooser = new JFileChooser();
        if (chooser.showSaveDialog(frame) == JFileChooser.APPROVE_OPTION) {
            File file = chooser.getSelectedFile();
            try (BufferedWriter writer = new BufferedWriter(new FileWriter(file))) {
                writer.write(textArea.getText());
            } catch (IOException e) {
                System.out.println("Error saving file: " + e.getMessage());
            }
        }
    }

    private void loadFromFile() {
        JFileChooser chooser = new JFileChooser();
        if (chooser.showOpenDialog(frame) == JFileChooser.APPROVE_OPTION) {
            File file = chooser.getSelectedFile();
            try (BufferedReader reader = new BufferedReader(new FileReader(file))) {
                textArea.setText(reader.lines().collect(Collectors.joining("\n")));
            } catch (IOException e) {
                System.out.println("Error loading file: " + e.getMessage());
            }
        }
    }

    private void close() {
        frame.dispose();
    }
}

这个程序创建了一个简单的窗口，包含一个文本区域用于显示或编辑文本，以及三个按钮用来保存、加载和关闭。用户可以通过选择文件来保存或读取内容。