多线程模拟售票

Posted 2020-11-09

需求:某电影院出售某些电影的票(复联3,红高粱....),有三个窗口同时进行售票(100张票),请您设计一个程序,模拟电影院售票
两种方式:
继承
接口
（1）synchronized实现
public class SellTicketDemo {

public static void main(String[] args) {

//创建资源类对象(共享资源类/目标对象)
    SellTicket st = new SellTicket() ;

    //创建线程类对象
    Thread t1 = new Thread(st, "窗口1") ;
    Thread t2 = new Thread(st ,"窗口2") ;
    Thread t3 = new Thread(st, "窗口3") ;
    //启动线程
    st1.start();
    st2.start();
    st3.start();
}

}
public class SellTicket implements Runnable {

//定义100张票
private int tickets = 100 ;

private Object obj = new Object() ;

@Override
public void run() {
    while(true) {

        //new Object():锁对象 (门和关)
        //t1,t2,t3
        synchronized(obj) {//t1进来,门一关,t2,t3进不来了
            if(tickets>0) {
                try {
                    //睡眠:延迟
                    Thread.sleep(100); 
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(Thread.currentThread().getName()
                        +"正在出售第"+(tickets--)+"张票");//0,-1
            }
        }

    }
}

}
（2）Lock实现
//测试类
public class SellTicketDemo {

public static void main(String[] args) {

    SellTicket st = new SellTicket() ;

    Thread t1 = new Thread(st,"窗口1") ;
    Thread t2 = new Thread(st,"窗口2") ;
    Thread t3 = new Thread(st,"窗口3") ;
    //启动线程
    t1.start(); 
    t2.start(); 
    t3.start();
}

}
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class SellTicket implements Runnable {

// 定义票
private int tickets = 100;
// Object obj = new Object();

// Jdk5.0以后,java提供了一个具体的锁: 接口:Lock
private Lock lock= new ReentrantLock(); //显示获取锁的前提,一定要创建Lock接口对象

@Override
public void run() {
    while (true) {
        try { //try...finally
            lock.lock(); // 获取锁    syncrhonized(obj)
            if (tickets > 0) {
                try {
                    Thread.sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

                System.out.println(Thread.currentThread().getName() + "正在出售第" + (tickets--) + "张票");
            }

        } finally {//释放锁
            if(lock!=null) {
                lock.unlock();
            }

        }

    }

}

}