java多线程模拟实现售票功能

Java多线程模拟实现售票功能，主要涉及Java的并发编程和线程同步操作。以下是实现该功能的步骤：

步骤一：创建Ticket类及构造方法

public class Ticket {
    private int num;

    public Ticket(int num) {
        this.num = num;
    }

    public int getNum() {
        return num;
    }

    public void setNum(int num) {
        this.num = num;
    }
}

注释：该类表示售票的对象，其中num表示剩余票数。

步骤二：创建Thread子类TicketSeller

public class TicketSeller extends Thread {
    private final Ticket ticket;
    private int nums;

    public TicketSeller(Ticket ticket, int nums, String name) {
        super(name);
        this.ticket = ticket;
        this.nums = nums;
    }

    @Override
    public void run() {
        while (ticket.getNum() > 0) {
            synchronized (ticket) {
                if (ticket.getNum() - nums >= 0) {
                    ticket.setNum(ticket.getNum() - nums);
                    System.out.println(Thread.currentThread().getName() + " sale " + nums + " tickets, there are " + ticket.getNum() + " left." );
                } else {
                    System.err.println(Thread.currentThread().getName() + " sale " + ticket.getNum() + " tickets, the ticket has sold out.");
                    break;
                }
            }
            try {
                // 模拟售票时间
                Thread.sleep(50);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

注释：该类继承自Thread类，主要用于售票线程的实现。其中，ticket表示售票对象，nums表示每次售票的数量。在run()方法中，通过synchronized关键字来实现线程同步。

步骤三：创建TicketSellerTest类

public class TicketSellerTest {
    public static void main(String[] args) {
        Ticket ticket = new Ticket(100);//创建售票对象
        TicketSeller seller1 = new TicketSeller(ticket, 1, "售票窗口1");
        TicketSeller seller2 = new TicketSeller(ticket, 2, "售票窗口2");
        seller1.start();
        seller2.start();
    }
}

注释：该类为测试类，主要用于执行售票功能的调用。其中，创建售票对象ticket，同时创建两个售票窗口seller1和seller2。创建并启动售票线程。

步骤四：测试结果

运行TicketSellerTest类，运行结果如下：

售票窗口1 sale 1 tickets, there are 99 left.
售票窗口2 sale 2 tickets, there are 97 left.
售票窗口1 sale 1 tickets, there are 96 left.
售票窗口2 sale 2 tickets, there are 94 left.
售票窗口1 sale 1 tickets, there are 93 left.
售票窗口2 sale 2 tickets, there are 91 left.
售票窗口1 sale 1 tickets, there are 90 left.
售票窗口2 sale 2 tickets, there are 88 left.
...

注释：售票窗口1和售票窗口2异步售票，两个窗口共同售出了售票对象ticket中的100张票。

示例说明

1. 如果将TicketSeller类的run()方法中synchronized改为锁住当前类对象，则每次只有一个线程能卖到票，其余线程都无法访问，从而失败。这说明线程同步的作用。
2. 如果将Ticket类的构造方法中num改为0，则TicketSeller类的run()方法中不会进入循环，从而不会售票。这说明必须保证售票对象中票数大于0，否则售票无法进行。