8.多线程死锁demo及其解决方案

最新推荐文章于 2025-07-07 15:23:49 发布

原创最新推荐文章于 2025-07-07 15:23:49 发布 · 514 阅读

0 ·

CC 4.0 BY-SA版权

4.并发编程专栏收录该内容

22 篇文章

订阅专栏

本文通过一个简单的Java代码示例展示了线程死锁的现象，两个线程分别持有资源并请求对方持有的资源，导致双方陷入等待状态。死锁的解决方法包括避免锁的嵌套使用、设置锁的超时、按特定顺序获取锁等策略。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

Java线程死锁demo

当线程中的同步代码有多个嵌套同步锁时容易发生死锁，下面的例子中2个线程公用2锁，一个拿着钱，要饭，一个拿着饭，要钱，互相不给，所以可能造成死锁现象：

package dielock;

public class Money implementsRunnable{
    private Object money;
    private Object food;

    public Money(Objectmoney, Object food) {
        this.money = money;
        this.food = food;
    }

   @Override
    public void run() {
        synchronized (money) {
            System.out.println("现在我拿着钱，但是我要先吃饭");
            try {
                Thread.sleep(0);
            } catch (InterruptedExceptione) {
                e.printStackTrace();
            }
            synchronized (food) {
                System.out.println("死锁解除");
            }
        }
    }
}

package dielock;

public class Food implements Runnable{
        private Object money;
        private Object food;

        public Food(Object money, Object food) {
            this.money = money;
            this.food = food;
        }

        @Override
        public void run() {
            synchronized (food) {
                System.out.println("现在我拿着饭，但是我要先要钱");
                try {
                    Thread.sleep(0);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                synchronized (money) {
                    System.out.println("死锁解除");
                }
            }
        }


}

package dielock;

public class test {
    public static void main(String[] args) {
        Object money = new Object();
        Object food = new Object();

        Food food1 = new Food(money, food);
        Money money1 = new Money(money, food);

        Thread thread = new Thread(food1);
        Thread thread1 = new Thread(money1);
        thread.start();
        thread1.start();
    }
}

可以看出锁住了，没有死锁解除的字样。但是有时候也可能会有，就是一个人同时拿到两个锁，

弄完了释放2个资源给对方，如下：但是概率太小了。

package dielock;

public class Food implementsRunnable{
        private Object money;
        private Object food;

        public Food(Objectmoney, Object food) {
            this.money = money;
            this.food = food;
        }

        @Override
        public void run() {
            synchronized (money) {
                System.out.println("现在我拿着饭，但是可以给你先吃饭，再给钱");
                try {
                    Thread.sleep(0);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                synchronized (food) {
                    System.out.println("收到钱了谢谢亲");
                }
            }
        }

}

package dielock;

public class test {
    public static void main(String[] args) {
        Object money = new Object();
        Object food = new Object();

        Food food1 = new Food(money, food);
        Money money1 = new Money(money, food);

        Thread thread = new Thread(food1);
        Thread thread1 = new Thread(money1);
        thread1.start();
        thread.start();

    }
}