java 多线程的售票问题

java 多线程的售票问题

1. 对票的库存进行操作

    public class Tickets  implements Runnable{
        private int ticket = 100;
        public void run() {
            while (true) {
                if ( ticket > 0 ) {
                    try{
                        Thread.sleep(10);
                    }catch (Exception e) {
                        e.printStackTrace();
                    }
                    System.out.println(Thread.currentThread().getName()+" 出售第 "+ticket--);
                }
            }
        }
    }

1. 开启多个线程同事操作票的库存

    public class ThDemo {
    public static void main(String[] args) {
        Tickets tickets = new Tickets();
        Thread t0 = new Thread(tickets);
        t0.setName("1hao");
        Thread t1 = new Thread(tickets);
        t1.setName("2hao");
        Thread t2 = new Thread(tickets);
        t2.setName("3hao");
        t0.start();
        t1.start();
        t2.start();
    }
}

1. 结果是库存数减到负数还可以售票， 利用同步代码块解决这个问题

    public class Tickets  implements Runnable{
        private int ticket = 100;
        private Object obj = new Object();
        public void run() {
            while (true) {
                synchronized (obj) {
                    if ( ticket > 0 ) {
                        try{
                            Thread.sleep(10);
                        }catch (Exception e) {
                            e.printStackTrace();
                        }
                        System.out.println(Thread.currentThread().getName()+" 出售第 "+ticket--);
                    }
                }
            }
        }
    }