用菜单+CardLayout 布局，通过录入界面将多人的通讯录写入文件“通讯录.txt”，点击“显示”菜单项，显示通讯录

好的，这里是一个基于菜单+CardLayout布局的Java通讯录程序示例，可以将多人的通讯录写入文件并读取并显示通讯录。

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

public class AddressBook extends JFrame implements ActionListener {

    private static final long serialVersionUID = 1L;
    private CardLayout cardLayout;
    private JPanel cardPanel;
    private JTextArea displayArea;
    private JTextField nameField, phoneField, emailField;
    private JButton addButton, saveButton;

    public AddressBook() {
        super("Address Book");

        // Create menu bar
        JMenuBar menuBar = new JMenuBar();
        setJMenuBar(menuBar);

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

        // Create "Add" menu item
        JMenuItem addMenuItem = new JMenuItem("Add");
        addMenuItem.addActionListener(this);
        fileMenu.add(addMenuItem);

        // Create "Save" menu item
        JMenuItem saveMenuItem = new JMenuItem("Save");
        saveMenuItem.addActionListener(this);
        fileMenu.add(saveMenuItem);

        // Create "Display" menu item
        JMenuItem displayMenuItem = new JMenuItem("Display");
        displayMenuItem.addActionListener(this);
        fileMenu.add(displayMenuItem);

        // Create card panel
        cardLayout = new CardLayout();
        cardPanel = new JPanel(cardLayout);
        getContentPane().add(cardPanel);

        // Create "Add" panel
        JPanel addPanel = new JPanel(new GridLayout(3, 2));
        addPanel.add(new JLabel("Name:"));
        nameField = new JTextField();
        addPanel.add(nameField);
        addPanel.add(new JLabel("Phone:"));
        phoneField = new JTextField();
        addPanel.add(phoneField);
        addPanel.add(new JLabel("Email:"));
        emailField = new JTextField();
        addPanel.add(emailField);
        addButton = new JButton("Add");
        addButton.addActionListener(this);
        addPanel.add(addButton);
        cardPanel.add(addPanel, "ADD");

        // Create "Display" panel
        JPanel displayPanel = new JPanel(new BorderLayout());
        displayArea = new JTextArea();
        JScrollPane scrollPane = new JScrollPane(displayArea);
        displayPanel.add(scrollPane, BorderLayout.CENTER);
        cardPanel.add(displayPanel, "DISPLAY");

        // Set default panel
        cardLayout.show(cardPanel, "ADD");

        // Set frame properties
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setSize(400, 300);
        setLocationRelativeTo(null);
        setVisible(true);
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == addButton) {
            // Add contact to file
            String name = nameField.getText().trim();
            String phone = phoneField.getText().trim();
            String email = emailField.getText().trim();
            if (!name.isEmpty() && !phone.isEmpty() && !email.isEmpty()) {
                try {
                    FileWriter fileWriter = new FileWriter("通讯录.txt", true);
                    fileWriter.write(name + "," + phone + "," + email + "\n");
                    fileWriter.close();
                    JOptionPane.showMessageDialog(this, "Contact added.");
                    nameField.setText("");
                    phoneField.setText("");
                    emailField.setText("");
                } catch (IOException ex) {
                    JOptionPane.showMessageDialog(this, "Error: " + ex.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
                }
            } else {
                JOptionPane.showMessageDialog(this, "Please fill in all fields.", "Error", JOptionPane.ERROR_MESSAGE);
            }
        } else if (e.getSource() == saveButton) {
            // Save contacts to file
            try {
                FileWriter fileWriter = new FileWriter("通讯录.txt", false);
                fileWriter.write(displayArea.getText());
                fileWriter.close();
                JOptionPane.showMessageDialog(this, "Contacts saved.");
            } catch (IOException ex) {
                JOptionPane.showMessageDialog(this, "Error: " + ex.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
            }
        } else if (e.getActionCommand().equals("Display")) {
            // Display contacts in text area
            try {
                BufferedReader bufferedReader = new BufferedReader(new FileReader("通讯录.txt"));
                String line;
                StringBuilder stringBuilder = new StringBuilder();
                while ((line = bufferedReader.readLine()) != null) {
                    String[] parts = line.split(",");
                    stringBuilder.append("Name: ").append(parts[0]).append("\n");
                    stringBuilder.append("Phone: ").append(parts[1]).append("\n");
                    stringBuilder.append("Email: ").append(parts[2]).append("\n\n");
                }
                bufferedReader.close();
                displayArea.setText(stringBuilder.toString());
                cardLayout.show(cardPanel, "DISPLAY");
            } catch (IOException ex) {
                JOptionPane.showMessageDialog(this, "Error: " + ex.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
            }
        } else if (e.getActionCommand().equals("Add")) {
            // Switch to add panel
            cardLayout.show(cardPanel, "ADD");
        } else if (e.getActionCommand().equals("Save")) {
            // Switch to save panel
            saveButton = new JButton("Save");
            saveButton.addActionListener(this);
            JPanel savePanel = new JPanel(new BorderLayout());
            savePanel.add(new JScrollPane(displayArea), BorderLayout.CENTER);
            savePanel.add(saveButton, BorderLayout.SOUTH);
            cardPanel.add(savePanel, "SAVE");
            cardLayout.show(cardPanel, "SAVE");
        }
    }

    public static void main(String[] args) {
        new AddressBook();
    }

}

在该程序中，我们使用了JFrame、JMenuBar、JMenu、JMenuItem、CardLayout、JPanel、JTextArea、JTextField和JButton等Swing组件。其中，JMenuBar、JMenu和JMenuItem用于创建菜单栏和菜单项，CardLayout和JPanel用于实现多个面板的切换，JTextArea、JTextField和JButton用于录入、显示和保存通讯录信息。

在程序中，我们首先创建了菜单栏和菜单项，并将它们添加到窗口的顶部。然后，我们创建了一个CardLayout布局的JPanel，并在其中添加了两个面板：录入面板和显示面板。录入面板包含三个文本框和一个“添加”按钮，用于录入通讯录信息并将其写入文件。显示面板包含一个文本区域，用于显示从文件中读取的通讯录信息。我们使用了CardLayout布局，使得录入面板和显示面板可以在需要时进行切换。当用户点击“显示”菜单项时，程序会读取文件中的通讯录信息，并在文本区域中显示它们。当用户点击“添加”菜单项时，程序会切换到录入面板，以便用户可以录入新的通讯录信息。当用户点击“保存”菜单项时，程序会切换到一个新的面板，该面板包含一个文本区域和一个“保存”按钮，用于编辑并保存通讯录信息。

请注意，在该程序中，我们将通讯录信息保存在名为“通讯录.txt”的文件中。如果您想要将文件保存在不同的位置或使用不同的文件名，请相应地更改代码。