java之多线程抢火车票

我不是女神ヾ 2023-10-08 18:45 25阅读 0赞

一、创建线程的方法是实现runnable，重写run方法，执行线程需要丢入runnable接口实现类,调用start方法

*********************************/
    //多个线程同时操作一个类
        //火车票
    public class TestTread4 implements Runnable{
    
        //票数
       private int ticketNums = 10;
        @Override
        public void run() {
    
            while (true) {
                if (ticketNums <= 0) {
                    break;
                }
                try {
                    Thread.sleep(200);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+"--->拿到了第"+ticketNums-- +"张票");
            }
    
        }
    
        public static void main(String[] args) {
            TestTread4 testTread4 = new TestTread4();
    
            new Thread(testTread4, "小明").start();
            new Thread(testTread4,"老师").start();
            new Thread(testTread4,"黄牛").start();
        }
    }

发现问题:多个线程操作同一个资源的情况下,线程不安全，数据紊乱.

![6e2825f76c47414db5a6ab4fba693e8a.png][]

加上锁就搞定

public class TestTread4 implements Runnable{
    
        //票数
       private int ticketNums = 10;
        @Override
        public synchronized void run() {
    
            while (true) {
                if (ticketNums <= 0) {
                    break;
                }
                try {
                    Thread.sleep(200);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()+"--->拿到了第"+ticketNums-- +"张票");
            }
    
        }
    
        public static void main(String[] args) {
            TestTread4 testTread4 = new TestTread4();
    
            new Thread(testTread4, "小明").start();
            new Thread(testTread4,"老师").start();
            new Thread(testTread4,"黄牛").start();
        }
    }

当有200人抢100张票

public class TicketRunnable implements Runnable {
    
        /**
         * 总票数
         */
        private final int ticketSize = 100;
    
        /**
         * 抢票人数
         */
        private final int peopleSize = 200;
    
        /**
         * 票数
         */
        private int ticketNum;
    
        /**
         * 人数
         */
        private int peopleNum;
    
        @Override
        public void run() {
            while(ticketNum < ticketSize && peopleNum < peopleSize){
                synchronized (this){
                    if(ticketNum < ticketSize && peopleNum < peopleSize){
                        if((int)(Math.random() * 20) % 2 == 1){
                            System.out.println(Thread.currentThread().getName() + "第" + (++peopleNum) + "个人抢到第" + (++ticketNum) + " 张票");
                        try {
                            Thread.sleep(100);
                        }catch (Exception e){
                            e.printStackTrace();
                        }
                        }else {
                            System.out.println(Thread.currentThread().getName() + "第" + (++peopleNum) + " 个人未抢到票");
                        }
                    }
                }
            }
    
        }
    }

public class TestTicket {
        public static void main(String[] args) {
            TicketRunnable tr = new TicketRunnable();
            Thread t1 = new Thread(tr , "窗口A");
            Thread t2 = new Thread(tr , "窗口B");
            Thread t3 = new Thread(tr , "窗口C");
            Thread t4 = new Thread(tr , "窗口D");
            t1.start();
            t2.start();
            t3.start();
            t4.start();
        }
    }

[6e2825f76c47414db5a6ab4fba693e8a.png]: https://img-blog.csdnimg.cn/6e2825f76c47414db5a6ab4fba693e8a.png