银行排队机程序Java

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.sql.*;
import java.util.Random;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class BankQueueMachine implements ActionListener {
    private JFrame frame;
    private JLabel ticketDisplay;
    private JButton callButton;
    private Connection connection;
    private ExecutorService threadPool;

    public BankQueueMachine() {
        frame = new JFrame("Bank Queue Machine");
        ticketDisplay = new JLabel("Ticket #");
        callButton = new JButton("Call Next");
        callButton.addActionListener(this);

        frame.setLayout(new FlowLayout());
        frame.add(ticketDisplay);
        frame.add(callButton);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);

        threadPool = Executors.newFixedThreadPool(5); // 创建一个固定大小的线程池，表示有5个柜员
    }

    public void connectToDatabase() {
        try {
            String url = "jdbc:postgresql://localhost:5432/dbname";
            String user = "username";
            String password = "password";
            connection = DriverManager.getConnection(url, user, password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == callButton) {
            threadPool.execute(new CallNextTask());
        }
    }

    private class CallNextTask implements Runnable {
        public void run() {
            try {
                Statement statement = connection.createStatement();
                ResultSet resultSet = statement.executeQuery("SELECT MIN(ticket_number) FROM queue");
                if (resultSet.next()) {
                    int nextTicketNumber = resultSet.getInt(1);
                    Random rand = new Random();
                    int delay = rand.nextInt(5000) + 1000; // 每个号码之间随机延迟1到6秒钟
                    Thread.sleep(delay);
                    ticketDisplay.setText("Ticket #" + nextTicketNumber);
                    statement.executeUpdate("DELETE FROM queue WHERE ticket_number = " + nextTicketNumber);
                    statement.executeUpdate("INSERT INTO call_records (ticket_number) VALUES (" + nextTicketNumber + ")");
                }
            } catch (SQLException | InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        BankQueueMachine bankQueueMachine = new BankQueueMachine();
        bankQueueMachine.connectToDatabase();
    }
}