Java多线程理解：死锁问题实例-蒲公英云

Java多线程理解：死锁问题实例

原创向右看齐 2024-10-25 09:24 140阅读 0赞

死锁是多线程编程中的一种严重问题，它发生在两个或更多线程相互等待对方释放资源，从而形成的一种僵局。

以下是一个简单的Java多线程死锁问题实例：

// 线程1需要资源A和B
public class ResourceA {
    private Object resource = new Object();
    public synchronized void acquire() throws InterruptedException {
        while (resource != null) {
            await();
        }
        resource = new Object(); // 资源被占用
    }
    public synchronized void release() {
        resource = null; // 资源被释放
        notifyAll(); // 通知等待的线程
    }
}
public class ResourceB {
    private Object resource = new Object();
    public synchronized void acquire() throws InterruptedException {
        while (resource != null) {
            await();
        }
        resource = new Object(); // 资源被占用
    }
    public synchronized void release() {
        resource = null; // 资源被释放
        notifyAll(); // 通知等待的线程
    }
}
public class DeadlockExample implements Runnable {
    private ResourceA resourceA;
    private ResourceB resourceB;
    public DeadlockExample(ResourceA resourceA, ResourceB resourceB) {
        this.resourceA = resourceA;
        this.resourceB = resourceB;
    }
    @Override
    public void run() {
        try {
            // 线程1获取资源A
            resourceA.acquire();
            // 线程2获取资源B
            resourceB.acquire();
            // 死锁形成，两个线程无法同时执行
            System.out.println("Deadlock detected");
        } catch (InterruptedException e) {
            e.printStackTrace();
        } finally {
            // 释放资源
            resourceA.release();
            resourceB.release();
        }
    }
}
public class Main {
    public static void main(String[] args) {
        ResourceA resourceA = new ResourceA();
        ResourceB resourceB = new ResourceB();
        Thread thread1 = new Thread(new DeadlockExample(resourceA, resourceB)), "Thread 1");
        Thread thread2 = new Thread(new DeadlockExample(resourceA, resourceB))), "Thread 2");
        thread1.start();
        thread2.start();
    }
}