自旋锁的java实现

package com.pimee.lock;

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

/**
 * 自旋锁
 */
public class SpinLockDemo {
    // 共享
    AtomicReference<Thread> atomicReference = new AtomicReference<>();

    /**
     * 加锁
     */
    public void lock(){
        Thread thread = Thread.currentThread();
        System.out.println(thread.getName() + " 进入获取锁");
        while(!atomicReference.compareAndSet(null, thread)){
            System.out.println(thread.getName() + " 自旋等待");
        }
    }

    /**
     * 释放锁
     */
    public void unlock(){
        Thread thread = Thread.currentThread();
        System.out.println(thread.getName() + " 进入释放锁");
        while(!atomicReference.compareAndSet(thread, null)){
            System.out.println(thread.getName() + " 自旋释放锁");
        }
        System.out.println(thread.getName() + "释放锁成功，退出");
    }

    public static void main(String[] args) throws InterruptedException {
        SpinLockDemo lock = new SpinLockDemo();
        // 线程1
        new Thread(()->{
            lock.lock();
            try {
                TimeUnit.SECONDS.sleep(3);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }finally {
                lock.unlock();
            }
        }, "T1").start();

        TimeUnit.SECONDS.sleep(1);
        // 线程2
        new Thread(()->{
            try {
                lock.lock();
            }finally {
                lock.unlock();
            }
        }, "T2").start();

    }
}

结果输出：

T1 进入获取锁
T2 进入获取锁
T1 进入释放锁
T1释放锁成功，退出
T2 进入释放锁
T2释放锁成功，退出