java实训 | 低配版模拟火车订票系统

代码： 

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.util.ArrayList;
import java.util.List;

public class TrainBookingSystem {

    private JFrame frame;
    private JPanel loginPanel, mainPanel;
    private JTextField usernameField;
    private JPasswordField passwordField; // 改为JPasswordField
    private JTextField departureField, destinationField;
    private JButton searchButton;
    private List<Train> trainList;
    private List<Order> paidOrders;
    private List<Order> waitingListOrders;
    private List<Order> myTickets;
    private JPanel paidPanel, waitingListPanel, myTicketsPanel;

    public TrainBookingSystem() {
        frame = new JFrame("12306 Train Booking System");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(800, 600);

        createLoginInterface();
        initTrainData();
        paidOrders = new ArrayList<>();
        waitingListOrders = new ArrayList<>();
        myTickets = new ArrayList<>();
    }

    private void createLoginInterface() {
        loginPanel = new JPanel(new BorderLayout());
        loginPanel.add(createWelcomeLabel(), BorderLayout.NORTH);

        JPanel authPanel = new JPanel(new GridBagLayout());
        GridBagConstraints constraints = new GridBagConstraints();
        constraints.insets = new Insets(10, 5, 10, 5);
        constraints.fill = GridBagConstraints.HORIZONTAL;

        constraints.gridx = 0;
        constraints.gridy = 0;
        authPanel.add(new JLabel("账号:"), constraints);
        constraints.gridx = 1;
        authPanel.add(usernameField = new JTextField(30), constraints);

        constraints.gridx = 0;
        constraints.gridy = 1;
        authPanel.add(new JLabel("密码:"), constraints);
        constraints.gridx = 1;
        authPanel.add(passwordField = new JPasswordField(30), constraints);

        JButton loginButton = new JButton("登录");
        loginButton.addActionListener(e -> login());
        constraints.gridx = 0;
        constraints.gridy = 2;
        constraints.gridwidth = 2; // 按钮横跨两列
        authPanel.add(loginButton, constraints); // 移除多余的参数

        loginPanel.add(authPanel, BorderLayout.CENTER);
        frame.setContentPane(loginPanel);
        frame.setLocationRelativeTo(null);
        frame.setVisible(true);
    }

    private JLabel createWelcomeLabel() {
        JLabel welcomeLabel = new JLabel("欢迎使用12306订票系统");
        Font font = new Font("SansSerif", Font.BOLD, 24);
        welcomeLabel.setFont(font);
        welcomeLabel.setHorizontalAlignment(SwingConstants.CENTER);
        return welcomeLabel;
    }

    private void login() {
        String username = usernameField.getText();
        char[] passwordChars = passwordField.getPassword();
        String password = new String(passwordChars);

        if (!username.isEmpty() && !password.isEmpty()) {
            // 登录逻辑
            frame.setContentPane(createMainInterface());
            frame.revalidate();
            frame.repaint();
        } else {
            JOptionPane.showMessageDialog(frame, "请输入账号和密码！");
        }
    }

    private JPanel createMainInterface() {
        mainPanel = new JPanel(new BorderLayout());

        // 左侧面板
        JPanel leftPanel = new JPanel(new BorderLayout());
        leftPanel.setPreferredSize(new Dimension((int)(frame.getWidth() * 0.75), frame.getHeight()));
        leftPanel.setBorder(BorderFactory.createTitledBorder("车票查询"));

        JPanel inputPanel = new JPanel(new GridBagLayout());
        GridBagConstraints gbc = new GridBagConstraints();
        gbc.anchor = GridBagConstraints.WEST;
        gbc.insets = new Insets(10, 5, 10, 5);

        gbc.gridx = 0;
        gbc.gridy = 0;
        inputPanel.add(new JLabel("始发站:"), gbc);
        gbc.gridx = 1;
        gbc.gridwidth = 2;
        inputPanel.add(departureField = new JTextField(30), gbc);

        gbc.gridx = 0;
        gbc.gridy = 1;
        inputPanel.add(new JLabel("终点站:"), gbc);
        gbc.gridx = 1;
        inputPanel.add(destinationField = new JTextField(30), gbc);

        searchButton = new JButton("车次查询");
        searchButton.addActionListener(e -> showTrainList());
        gbc.gridx = 0;
        gbc.gridy = 2;
        gbc.gridwidth = 3;
        inputPanel.add(searchButton, gbc);

        leftPanel.add(inputPanel, BorderLayout.CENTER);

        // 右侧面板
        JPanel rightPanel = new JPanel(new GridLayout(3, 1)); // 3行1列的网格布局
        rightPanel.setPreferredSize(new Dimension(frame.getWidth() / 4, frame.getHeight()));
        rightPanel.setBorder(BorderFactory.createTitledBorder("个人订单查询"));

        // 初始化面板并添加到右侧面板
        paidPanel = new JPanel(new FlowLayout());
        waitingListPanel = new JPanel(new FlowLayout());
        myTicketsPanel = new JPanel(new FlowLayout());

        // 订单管理按钮初始化并添加到右侧面板
        JButton paidOrdersButton = new JButton("已支付");
        paidOrdersButton.addActionListener(e -> showOrders(paidOrders));
        rightPanel.add(paidOrdersButton, BorderLayout.NORTH);

        // 注意：需要将候补订单按钮添加到面板上
        JButton waitingListOrdersButton = new JButton("候补订单");
        waitingListOrdersButton.addActionListener(e -> showOrders(waitingListOrders));
        // 将候补订单按钮添加到rightPanel中
        rightPanel.add(waitingListOrdersButton, BorderLayout.CENTER);

        JButton myTicketsButton = new JButton("本人车票");
        myTicketsButton.addActionListener(e -> showOrders(myTickets));
        rightPanel.add(myTicketsButton, BorderLayout.SOUTH);

        rightPanel.add(new JLabel(" "), BorderLayout.CENTER);

        mainPanel.add(leftPanel, BorderLayout.CENTER);
        mainPanel.add(rightPanel, BorderLayout.EAST);

        // 初始订单显示更新
        updateOrderDisplays();
        return mainPanel;
    }
    private void showOrders(List<Order> orders) {
        if (orders.isEmpty()) {
            JOptionPane.showMessageDialog(frame, "当前没有订单！");
        } else {
            String message = "订单信息：\n";
            for (Order order : orders) {
                message += order.toString() + "\n";
            }
            JOptionPane.showMessageDialog(frame, message, "订单列表", JOptionPane.INFORMATION_MESSAGE);
        }
    }

    private void showTrainList() {
        JDialog dialog = new JDialog(frame, "车次列表", true);
        dialog.setLayout(new BorderLayout());
        dialog.setSize(400, 300);

        JPanel trainInfoPanel = new JPanel(new GridLayout(trainList.size(), 1));
        for (Train train : trainList) {
            JPanel trainPanel = new JPanel(new BorderLayout());
            JButton bookButton = new JButton("订票");
            JButton waitlistButton = new JButton("候补");
            waitlistButton.setVisible(false);

            bookButton.addActionListener(evt -> {
                if (train.book()) {
                    addOrder(train, true); // 订票成功
                    JOptionPane.showMessageDialog(frame, "订票成功！");
                    dialog.dispose();
                } else {
                    waitlistButton.setVisible(true);
                }
            });

            waitlistButton.addActionListener(evt -> {
                addOrder(train, false); // 候补票
                JOptionPane.showMessageDialog(frame, "候补成功！");
                dialog.dispose();
            });

            trainPanel.add(new JLabel(train.getTrainNumber() + " - " + train.getDepartureTime() + " - 剩余票数：" + train.getRemainingSeats()), BorderLayout.CENTER);
            JPanel buttonPanel = new JPanel(new FlowLayout());
            buttonPanel.add(bookButton);
            buttonPanel.add(waitlistButton);
            trainPanel.add(buttonPanel, BorderLayout.EAST);
            trainInfoPanel.add(trainPanel);
        }

        JScrollPane scrollPane = new JScrollPane(trainInfoPanel);
        dialog.add(scrollPane, BorderLayout.CENTER);
        dialog.setLocationRelativeTo(frame);
        dialog.setVisible(true);
    }

    private void addOrder(Train train, boolean isPaid) {
        Order order = new Order(train, isPaid);
        if (isPaid) {
            paidOrders.add(order);
            myTickets.add(order);
        } else {
            waitingListOrders.add(order);
        }
        updateOrderDisplays();
    }

    private void updateOrderDisplays() {
        // 此处不再需要removeAll，因为面板已经初始化
        paidPanel.removeAll();
        waitingListPanel.removeAll();
        myTicketsPanel.removeAll();

        // 直接添加订单信息
        for (Order order : paidOrders) {
            paidPanel.add(new JLabel(order.toString()));
        }
        for (Order order : waitingListOrders) {
            waitingListPanel.add(new JLabel(order.toString()));
        }
        for (Order order : myTickets) {
            myTicketsPanel.add(new JLabel(order.toString()));
        }

        paidPanel.repaint();
        waitingListPanel.repaint();
        myTicketsPanel.repaint();
    }

    private void initTrainData() {
        trainList = new ArrayList<>();
        trainList.add(new Train("G123", "08:00", 150));
        trainList.add(new Train("G124", "09:30", 100));
        trainList.add(new Train("G125", "11:00", 200));
        trainList.add(new Train("G126", "13:00", 0));
        trainList.add(new Train("G127", "15:00", 75));
    }

    class Train {
        private String trainNumber;
        private String departureTime;
        private int remainingSeats;

        public Train(String trainNumber, String departureTime, int remainingSeats) {
            this.trainNumber = trainNumber;
            this.departureTime = departureTime;
            this.remainingSeats = remainingSeats;
        }

        public String getTrainNumber() {
            return trainNumber;
        }

        public String getDepartureTime() {
            return departureTime;
        }

        public int getRemainingSeats() {
            return remainingSeats;
        }

        public boolean book() {
            if (remainingSeats > 0) {
                remainingSeats--;
                return true;
            }
            return false;
        }
    }

    class Order {
        private Train train;
        private boolean isPaid;

        public Order(Train train, boolean isPaid) {
            this.train = train;
            this.isPaid = isPaid;
        }

        @Override
        public String toString() {
            return isPaid ? "已支付: " + train.getTrainNumber() + " " + train.getDepartureTime() :
                    "候补: " + train.getTrainNumber() + " " + train.getDepartureTime();
        }
    }

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

代码注释：

// 导入Swing库，用于创建图形用户界面  
import javax.swing.*;   
// 导入AWT库，包含用于构建图形用户界面和图像、字体、颜色等资源的类  
import java.awt.*;   
// 导入AWT的事件处理库，用于处理如按钮点击等用户事件  
import java.awt.event.ActionEvent;   
// 导入Java的集合库，用于创建列表  
import java.util.ArrayList;   
import java.util.List;   
  
// 定义一个名为TrainBookingSystem的公共类，代表火车订票系统  
public class TrainBookingSystem {   
  
    // 声明多个私有成员变量，分别用于存储框架、面板、文本字段、按钮、火车列表和订单列表等  
    private JFrame frame;   
    private JPanel loginPanel, mainPanel;   
    private JTextField usernameField;   
    private JPasswordField passwordField; // 改用JPasswordField来更安全地处理密码输入  
    private JTextField departureField, destinationField;   
    private JButton searchButton;   
    private List<Train> trainList;   
    private List<Order> paidOrders;   
    private List<Order> waitingListOrders;   
    private List<Order> myTickets;   
    private JPanel paidPanel, waitingListPanel, myTicketsPanel;   
  
    // 构造函数，用于初始化系统  
    public TrainBookingSystem() {   
        // 创建框架并设置其标题、关闭操作和大小  
        frame = new JFrame("12306 Train Booking System");   
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);   
        frame.setSize(800, 600);   
  
        // 创建登录界面  
        createLoginInterface();   
  
        // 初始化火车数据  
        initTrainData();   
  
        // 初始化订单列表  
        paidOrders = new ArrayList<>();   
        waitingListOrders = new ArrayList<>();   
        myTickets = new ArrayList<>();   
    }   
  
    // 创建一个登录界面的方法  
    private void createLoginInterface() {   
        // 创建一个布局为BorderLayout的面板  
        loginPanel = new JPanel(new BorderLayout());   
  
        // 添加欢迎标签到面板的北部  
        loginPanel.add(createWelcomeLabel(), BorderLayout.NORTH);   
  
        // 创建一个用于账号和密码输入的面板，布局为GridBagLayout  
        JPanel authPanel = new JPanel(new GridBagLayout());   
        GridBagConstraints constraints = new GridBagConstraints();   
  
        // 设置GridBagConstraints对象，用于指定组件在GridBagLayout中的位置和填充方式  
        constraints.insets = new Insets(10, 5, 10, 5);   
        constraints.fill = GridBagConstraints.HORIZONTAL;   
  
        // 添加账号标签和文本字段到authPanel  
        constraints.gridx = 0;   
        constraints.gridy = 0;   
        authPanel.add(new JLabel("账号:"), constraints);   
        constraints.gridx = 1;   
        authPanel.add(usernameField = new JTextField(30), constraints);   
  
        // 添加密码标签和密码字段到authPanel  
        constraints.gridx = 0;   
        constraints.gridy = 1;   
        authPanel.add(new JLabel("密码:"), constraints);   
        constraints.gridx = 1;   
        authPanel.add(passwordField = new JPasswordField(30), constraints);   
  
        // 创建一个登录按钮并为其添加点击事件监听器  
        JButton loginButton = new JButton("登录");   
        loginButton.addActionListener(e -> login());   
  
        // 将登录按钮添加到authPanel，横跨两列  
        constraints.gridx = 0;   
        constraints.gridy = 2;   
        constraints.gridwidth = 2;   
        authPanel.add(loginButton, constraints);   
  
        // 将authPanel添加到loginPanel的中心区域  
        loginPanel.add(authPanel, BorderLayout.CENTER);   
  
        // 将loginPanel设置为框架的内容面板，并设置框架的位置和可见性  
        frame.setContentPane(loginPanel);   
        frame.setLocationRelativeTo(null);   
        frame.setVisible(true);   
    }   
  
    // 创建一个欢迎标签的方法  
    private JLabel createWelcomeLabel() {   
        // 创建一个标签并设置其文本、字体和对齐方式  
        JLabel welcomeLabel = new JLabel("欢迎使用12306订票系统");   
        Font font = new Font("SansSerif", Font.BOLD, 24);   
        welcomeLabel.setFont(font);
welcomeLabel.setHorizontalAlignment(SwingConstants.CENTER);   
        // 返回创建的欢迎标签  
        return welcomeLabel;   
    }   
  
    // 定义一个登录方法  
    private void login() {   
        // 从文本字段中获取账号和密码  
        String username = usernameField.getText();   
        char[] passwordChars = passwordField.getPassword();   
        String password = new String(passwordChars);   
  
        // 如果账号和密码都不为空，则执行登录逻辑  
        if (!username.isEmpty() && !password.isEmpty()) {   
            // 假设的登录逻辑（实际中应包含与数据库的交互）  
            // 将框架的内容面板更改为主界面，并重新验证和重绘框架  
            frame.setContentPane(createMainInterface());   
            frame.revalidate();   
            frame.repaint();   
        } else {   
            // 如果账号或密码为空，则显示错误消息  
            JOptionPane.showMessageDialog(frame, "请输入账号和密码！");   
        }   
    }   
  
    // 创建一个主界面的方法  
    private JPanel createMainInterface() {   
        // 创建一个布局为BorderLayout的主面板  
        mainPanel = new JPanel(new BorderLayout());   
  
        // 创建左侧的面板用于输入始发站和终点站  
        JPanel leftPanel = new JPanel(new BorderLayout());   
        leftPanel.setPreferredSize(new Dimension((int)(frame.getWidth() * 0.75), frame.getHeight()));   
        leftPanel.setBorder(BorderFactory.createTitledBorder("车票查询"));   
  
        // 创建一个用于输入始发站和终点站的面板，布局为GridBagLayout  
        JPanel inputPanel = new JPanel(new GridBagLayout());   
        GridBagConstraints gbc = new GridBagConstraints();   
  
        // 设置GridBagConstraints对象  
        gbc.anchor = GridBagConstraints.WEST;   
        gbc.insets = new Insets(10, 5, 10, 5);   
  
        // 添加始发站标签和文本字段到inputPanel  
        gbc.gridx = 0;   
        gbc.gridy = 0;   
        inputPanel.add(new JLabel("始发站:"), gbc);   
        gbc.gridx = 1;   
        gbc.gridwidth = 2;   
        inputPanel.add(departureField = new JTextField(30), gbc);   
  
        // 添加终点站标签和文本字段到inputPanel  
        gbc.gridx = 0;   
        gbc.gridy = 1;   
        inputPanel.add(new JLabel("终点站:"), gbc);   
        gbc.gridx = 1;   
        inputPanel.add(destinationField = new JTextField(30), gbc);   
  
        // 创建一个查询按钮并为其添加点击事件监听器  
        searchButton = new JButton("车次查询");   
        searchButton.addActionListener(e -> showTrainList());   
  
        // 将查询按钮添加到inputPanel，横跨三列  
        gbc.gridx = 0;   
        gbc.gridy = 2;   
        gbc.gridwidth = 3;   
        inputPanel.add(searchButton, gbc);   
  
        // 将inputPanel添加到leftPanel的中心区域  
        leftPanel.add(inputPanel, BorderLayout.CENTER);   
  
        // 创建右侧的面板用于显示个人订单  
        JPanel rightPanel = new JPanel(new GridLayout(3, 1)); // 3行1列的网格布局  
        rightPanel.setPreferredSize(new Dimension(frame.getWidth() / 4, frame.getHeight()));   
        rightPanel.setBorder(BorderFactory.createTitledBorder("个人订单查询"));   
  
        // 初始化并添加用于显示已支付订单、候补订单和本人车票的面板  
        paidPanel = new JPanel(new FlowLayout());   
        waitingListPanel = new JPanel(new FlowLayout());   
        myTicketsPanel = new JPanel(new FlowLayout());   
  
        // 创建订单管理按钮并为其添加点击事件监听器  
        JButton paidOrdersButton = new JButton("已支付");   
        paidOrdersButton.addActionListener(e -> showOrders(paidOrders));   
        rightPanel.add(paidOrdersButton, BorderLayout.NORTH); // 注意：这里应该是使用GridLayout，而不是BorderLayout  
  
        // 创建候补订单按钮并为其添加点击事件监听器  
        JButton waitingListOrdersButton = new JButton("候补订单");   
        waitingListOrdersButton.addActionListener(e -> showOrders(waitingListOrders));   
        rightPanel.add(waitingListOrdersButton, 1); // 在GridLayout中，
// 这里的索引参数在GridLayout中应该是一个数字，表示添加到第几行（从0开始）。  
        // 但是，因为GridLayout并没有直接提供索引来指定具体位置，  
        // 所以我们简单地按照顺序添加。在GridLayout中，组件会自动按行和列的布局进行排列。  
        rightPanel.add(waitingListOrdersButton); // 正确地添加候补订单按钮到rightPanel  
  
        // 创建本人车票按钮并为其添加点击事件监听器  
        JButton myTicketsButton = new JButton("本人车票");   
        myTicketsButton.addActionListener(e -> showOrders(myTickets));   
        rightPanel.add(myTicketsButton); // 将本人车票按钮添加到rightPanel  
  
        // 注意：这里添加了一个JLabel(" ")作为占位符是不必要的，因为GridLayout会自动处理布局  
        // rightPanel.add(new JLabel(" "), BorderLayout.CENTER); // 移除这个不必要的代码  
  
        // 将leftPanel和rightPanel添加到mainPanel中  
        mainPanel.add(leftPanel, BorderLayout.CENTER);   
        mainPanel.add(rightPanel, BorderLayout.EAST);   
  
        // 初始化并更新订单显示  
        updateOrderDisplays();   
  
        // 返回创建的主界面面板  
        return mainPanel;   
    }   
  
    // 显示订单列表的方法  
    private void showOrders(List<Order> orders) {   
        if (orders.isEmpty()) {   
            // 如果没有订单，则显示一个消息框提示没有订单  
            JOptionPane.showMessageDialog(frame, "当前没有订单！");   
        } else {   
            // 如果有订单，则创建一个消息框显示所有订单信息  
            String message = "订单信息：\n";   
            for (Order order : orders) {   
                message += order.toString() + "\n";   
            }   
            JOptionPane.showMessageDialog(frame, message, "订单列表", JOptionPane.INFORMATION_MESSAGE);   
        }   
    }   
  
    // 显示车次列表的方法  
    private void showTrainList() {   
        // 创建一个对话框用于显示车次列表  
        JDialog dialog = new JDialog(frame, "车次列表", true);   
        dialog.setLayout(new BorderLayout());   
        dialog.setSize(400, 300);   
  
        // 创建一个面板用于显示火车信息，布局为GridLayout，大小与trainList的大小一致  
        JPanel trainInfoPanel = new JPanel(new GridLayout(trainList.size(), 1));   
  
        // 遍历trainList中的每一辆火车  
        for (Train train : trainList) {   
            // 为每一辆火车创建一个面板  
            JPanel trainPanel = new JPanel(new BorderLayout());   
  
            // 创建订票和候补按钮  
            JButton bookButton = new JButton("订票");   
            JButton waitlistButton = new JButton("候补");   
            waitlistButton.setVisible(false); // 默认情况下不显示候补按钮  
  
            // 为订票按钮添加点击事件监听器  
            bookButton.addActionListener(evt -> {   
                if (train.book()) {   
                    // 如果订票成功，则添加订单并显示成功消息  
                    addOrder(train, true);   
                    JOptionPane.showMessageDialog(frame, "订票成功！");   
                    dialog.dispose(); // 关闭车次列表对话框  
                } else {   
                    // 如果订票失败（没有剩余座位），则显示候补按钮  
                    waitlistButton.setVisible(true);   
                }   
            });   
  
            // 为候补按钮添加点击事件监听器  
            waitlistButton.addActionListener(evt -> {   
                // 添加候补订单并显示成功消息  
                addOrder(train, false);   
                JOptionPane.showMessageDialog(frame, "候补成功！");   
                dialog.dispose(); // 关闭车次列表对话框  
            });   
  
            // 在trainPanel中添加火车信息和按钮  
            trainPanel.add(new JLabel(train.getTrainNumber() + " - " + train.getDepartureTime() + " - 剩余票数：" + train.getRemainingSeats()), BorderLayout.CENTER);   
            JPanel buttonPanel = new JPanel(new FlowLayout());   
            buttonPanel.add(bookButton);   
            buttonPanel.add(waitlistButton);   
            trainPanel.add(buttonPanel, BorderLayout.EAST);   
  
            // 将trainPanel添加到trainInfoPanel中  
            trainInfoPanel.add(trainPanel);   
        }   
  
// 创建一个滚动面板来包含trainInfoPanel，并添加到对话框中  
        JScrollPane scrollPane = new JScrollPane(trainInfoPanel);   
        dialog.add(scrollPane, BorderLayout.CENTER); // 将滚动面板添加到对话框的中心位置  
  
        // 设置对话框的位置相对于父窗口居中  
        dialog.setLocationRelativeTo(frame);   
  
        // 设置对话框为可见  
        dialog.setVisible(true);   
    }  
  
    // 添加订单到对应列表的方法  
    private void addOrder(Train train, boolean isPaid) {   
        Order order = new Order(train, isPaid); // 创建一个新的订单对象  
  
        // 根据订单是否已支付，将其添加到对应的列表中  
        if (isPaid) {   
            paidOrders.add(order); // 添加到已支付订单列表  
            myTickets.add(order); // 添加到本人车票列表  
        } else {   
            waitingListOrders.add(order); // 添加到候补订单列表  
        }  
  
        // 更新订单显示面板的内容  
        updateOrderDisplays();   
    }  
  
    // 更新订单显示面板的方法  
    private void updateOrderDisplays() {   
        // 清除之前的订单信息  
        paidPanel.removeAll();   
        waitingListPanel.removeAll();   
        myTicketsPanel.removeAll();   
  
        // 遍历订单列表，将订单信息添加到对应的面板中  
        for (Order order : paidOrders) {   
            paidPanel.add(new JLabel(order.toString()));   
        }  
        for (Order order : waitingListOrders) {   
            waitingListPanel.add(new JLabel(order.toString()));   
        }  
        for (Order order : myTickets) {   
            myTicketsPanel.add(new JLabel(order.toString()));   
        }  
  
        // 重新绘制面板以显示新的订单信息  
        paidPanel.repaint();   
        waitingListPanel.repaint();   
        myTicketsPanel.repaint();   
    }  
  
    // 初始化火车数据的方法  
    private void initTrainData() {   
        trainList = new ArrayList<>();   
  
        // 添加几辆火车到trainList中，包括车次、发车时间和剩余座位数  
        trainList.add(new Train("G123", "08:00", 150));   
        trainList.add(new Train("G124", "09:30", 100));   
        trainList.add(new Train("G125", "11:00", 200));   
        trainList.add(new Train("G126", "13:00", 0)); // 这辆火车没有剩余座位  
        trainList.add(new Train("G127", "15:00", 75));   
    }  
  
    // 火车类Train，表示一辆火车  
    class Train {   
        // ...（类的成员变量和方法省略，已在前面定义）  
  
        // book方法，尝试预订火车票  
        public boolean book() {   
            if (remainingSeats > 0) { // 如果剩余座位数大于0  
                remainingSeats--; // 预订成功后，剩余座位数减1  
                return true; // 返回true表示预订成功  
            }  
            return false; // 返回false表示预订失败（没有剩余座位）  
        }  
    }  
  
    // 订单类Order，表示一个订单  
    class Order {   
        // ...（类的成员变量和方法省略，已在前面定义）  
  
        // toString方法，返回订单的字符串表示形式  
        @Override   
        public String toString() {   
            return isPaid ? "已支付: " + train.getTrainNumber() + " " + train.getDepartureTime() :  
                           "候补: " + train.getTrainNumber() + " " + train.getDepartureTime();   
        }  
    }  
  
    // 主方法，程序入口  
    public static void main(String[] args) {   
        new TrainBookingSystem(); // 创建TrainBookingSystem对象，启动订票系统  
    }  
}