线程安全问题的代码实现和线程安全问题产生的原理

线程安全问题的代码实现

public class RunnableImpl implements Runnable{

    private int ticket = 100;
    //设置线程任务:卖票
    @Override
    public void run() {
        //使用死循环,让卖票操作重复执行while(true){
        //先判断票是否存在
        if(ticket>0){
            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

            //票存在,卖票ticket--
        System.out .println(Thread.currentThread( ).getName()+"-->正在卖第" +ticket+"张票"+ticket--);
        }
    }
}

 public static void main(String[] args) {
        RunnableImpl runnable = new RunnableImpl();
        Thread thread = new Thread(runnable);
        Thread thread1 = new Thread(runnable);
        Thread thread2 = new Thread(runnable);

        thread.start();
        thread1.start();
        thread2.start();
    }

class Counter {
    private int count;
    public void increase() {
        ++this.count;
    }
    public int getCount() {
        return this.count;
    }
}

public class Main11 {
    private static final int CNT = 50000;
    private static final Counter counter = new Counter();
    public static void main(String[] args) throws InterruptedException {

        Thread thread1 = new Thread(() -> {
            for (int i = 0; i < CNT; i++) {
                counter.increase();
            }
        });
        Thread thread2 = new Thread(() -> {
            for (int j = 0; j < CNT; j++) {
                counter.increase();
            }
        });

        thread1.start();
        thread2.start();

        thread1.join();
        thread2.join();

        System.out.println(counter.getCount());
    }
}

 

线程安全问题产生的原理