java自旋锁的代码实现

自旋锁：spinlock

是指尝试获取锁的线程不会立即阻塞，而是采用循环的方式获取锁，这样的好处是减少线程上下文切换的消耗，缺点是循环好用CPU

 代码：

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

public class SpinLockDemo {
    //原子引用线程
    AtomicReference<Thread> atomicReference = new AtomicReference<>();

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

        }
    }

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