Thread - 01 -浅谈synchronized的作用

public class demo {

    public static void main(String[] args) {
        Thread t1 = new Thread(new SaleThread(),"售票人员1");
        Thread t2 = new Thread(new SaleThread(),"售票人员2");
        Thread t3 = new Thread(new SaleThread(),"售票人员3");
        Thread t4 = new Thread(new SaleThread(),"售票人员4");
        Thread t5 = new Thread(new SaleThread(),"售票人员5");
        t1.start();
        t2.start();
        t3.start();
        t4.start();
        t5.start();
    }
}


class SaleThread implements Runnable {
    /**
    * 使用静态成员变量作为100张票的保存变量，是一个共享资源。
    */
    private static int tickets = 100;
    @Override
    public void run() {
    // 完成售票过程
        while (true) {
            /*
            字符串可以作为锁对象，因为双引号包含的字符串不管在代码中如何运行，有且只有一个
            */
            synchronized ("锁") {
                try {
                    Thread.sleep(10);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                if (tickets > 0) {
                    tickets--;
                    System.out.println(Thread.currentThread().getName() + "售出了1张票,余" + tickets + "张票");
                } else {
                    System.out.println(Thread.currentThread().getName() + "售罄！！！" + tickets);
                    break;
                }
            }
        }
    	System.out.println(tickets);
    }
}