请编写一个Java程序实现如下图所示的“我的记事本”窗口(TextEditor)，窗口 1 中包括一个菜单栏(JMenuBar)，其中有三个菜单（JMennu），分别是文件菜单、编辑 菜单和查看菜单，窗口的主体部分是一个可编辑区域，用到了多行多列的文本框 （JTextArea)和滚动条面板(JScrollPane):

import java.awt.BorderLayout;
import java.awt.EventQueue;
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.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.filechooser.FileNameExtensionFilter;

public class TextEditor extends JFrame {

    private JTextArea textArea;
    private JFileChooser fileChooser;
    private String currentFile = "";

    public TextEditor() {
        initUI();
    }

    private void initUI() {
        setTitle("我的记事本");
        setSize(800, 600);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setLocationRelativeTo(null);

        textArea = new JTextArea();
        textArea.setFont(new Font("微软雅黑", Font.PLAIN, 16));
        JScrollPane scrollPane = new JScrollPane(textArea);
        getContentPane().add(scrollPane, BorderLayout.CENTER);

        JMenuBar menuBar = new JMenuBar();
        JMenu fileMenu = new JMenu("文件");
        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");

        newItem.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                newFile();
            }
        });

        openItem.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                openFile();
            }
        });

        saveItem.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                saveFile();
            }
        });

        saveAsItem.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                saveFileAs();
            }
        });

        exitItem.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                System.exit(0);
            }
        });

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

        JMenu editMenu = new JMenu("编辑");
        JMenuItem cutItem = new JMenuItem("剪切");
        JMenuItem copyItem = new JMenuItem("复制");
        JMenuItem pasteItem = new JMenuItem("粘贴");
        JMenuItem selectAllItem = new JMenuItem("全选");

        cutItem.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                textArea.cut();
            }
        });

        copyItem.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                textArea.copy();
            }
        });

        pasteItem.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                textArea.paste();
            }
        });

        selectAllItem.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                textArea.selectAll();
            }
        });

        editMenu.add(cutItem);
        editMenu.add(copyItem);
        editMenu.add(pasteItem);
        editMenu.add(selectAllItem);

        JMenu viewMenu = new JMenu("查看");
        JMenuItem zoomInItem = new JMenuItem("放大");
        JMenuItem zoomOutItem = new JMenuItem("缩小");

        zoomInItem.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                Font font = textArea.getFont();
                textArea.setFont(new Font(font.getName(), font.getStyle(), font.getSize() + 1));
            }
        });

        zoomOutItem.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                Font font = textArea.getFont();
                textArea.setFont(new Font(font.getName(), font.getStyle(), font.getSize() - 1));
            }
        });

        viewMenu.add(zoomInItem);
        viewMenu.add(zoomOutItem);

        menuBar.add(fileMenu);
        menuBar.add(editMenu);
        menuBar.add(viewMenu);
        setJMenuBar(menuBar);
    }

    private void newFile() {
        currentFile = "";
        textArea.setText("");
    }

    private void openFile() {
        if (fileChooser == null) {
            fileChooser = new JFileChooser();
            FileNameExtensionFilter filter = new FileNameExtensionFilter("Text Files", "txt");
            fileChooser.setFileFilter(filter);
        }
        int returnVal = fileChooser.showOpenDialog(this);
        if (returnVal == JFileChooser.APPROVE_OPTION) {
            File file = fileChooser.getSelectedFile();
            currentFile = file.getAbsolutePath();
            try {
                BufferedReader reader = new BufferedReader(new FileReader(file));
                String line = reader.readLine();
                StringBuilder sb = new StringBuilder();
                while (line != null) {
                    sb.append(line).append("\n");
                    line = reader.readLine();
                }
                reader.close();
                textArea.setText(sb.toString());
            } catch (IOException ex) {
                JOptionPane.showMessageDialog(this, "打开文件失败", "错误", JOptionPane.ERROR_MESSAGE);
            }
        }
    }

    private void saveFile() {
        if (currentFile.isEmpty()) {
            saveFileAs();
        } else {
            try {
                BufferedWriter writer = new BufferedWriter(new FileWriter(currentFile));
                writer.write(textArea.getText());
                writer.close();
            } catch (IOException ex) {
                JOptionPane.showMessageDialog(this, "保存文件失败", "错误", JOptionPane.ERROR_MESSAGE);
            }
        }
    }

    private void saveFileAs() {
        if (fileChooser == null) {
            fileChooser = new JFileChooser();
            FileNameExtensionFilter filter = new FileNameExtensionFilter("Text Files", "txt");
            fileChooser.setFileFilter(filter);
        }
        int returnVal = fileChooser.showSaveDialog(this);
        if (returnVal == JFileChooser.APPROVE_OPTION) {
            File file = fileChooser.getSelectedFile();
            currentFile = file.getAbsolutePath();
            if (!currentFile.endsWith(".txt")) {
                currentFile += ".txt";
            }
            try {
                BufferedWriter writer = new BufferedWriter(new FileWriter(currentFile));
                writer.write(textArea.getText());
                writer.close();
            } catch (IOException ex) {
                JOptionPane.showMessageDialog(this, "保存文件失败", "错误", JOptionPane.ERROR_MESSAGE);
            }
        }
    }

    public static void main(String[] args) {
        try {
            // 设置LookAndFeel为系统默认
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException
                | UnsupportedLookAndFeelException e) {
            e.printStackTrace();
        }

        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                TextEditor editor = new TextEditor();
                editor.setVisible(true);
            }
        });
    }
}