java锁之自旋锁代码验证_java自旋代码-优快云博客

本文链接：https://blog.youkuaiyun.com/cute_coder/article/details/120111897

本文介绍了Java中的SpinLockDemo，通过AtomicReference实现自旋锁，演示了其无阻塞获取锁的过程，并在多线程环境下展示了其使用场景。自旋锁有助于减少上下文切换，但可能消耗CPU资源。

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import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;

/**
 * Created by cute coder
 * 2021/9/5 10:44
 */
public class SpinLockDemo {
    /**
     * 自旋锁 好处：循环获取锁，没有阻塞
     * 是指尝试获取锁的线程不会立即阻塞，而是采取循环的方式去获取锁，这样的好处是减少线程上下文切换的消耗，缺点是会消耗cpu
     */
    AtomicReference<Thread> atomicReference = new AtomicReference<>();

    public void myLock() {
        Thread thread = Thread.currentThread();
        System.out.println(Thread.currentThread().getName() + "\t come in");
        while (!atomicReference.compareAndSet(null, thread)) {

        }

    }

    public void myUnlock() {
        Thread thread = Thread.currentThread();
        atomicReference.compareAndSet(thread, null);
        System.out.println(Thread.currentThread().getName() + "\t invoke myUnlock");
    }

    public static void main(String[] args) {
        SpinLockDemo spinLockDemo = new SpinLockDemo();
        new Thread(() -> {
            spinLockDemo.myLock();
            try {
                TimeUnit.SECONDS.sleep(5);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            spinLockDemo.myUnlock();
        }, "AA").start();
        try {
            TimeUnit.SECONDS.sleep(1);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        new Thread(() -> {
            spinLockDemo.myLock();
            try {
                TimeUnit.SECONDS.sleep(1);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            spinLockDemo.myUnlock();
        }, "BB").start();
    }
}