说明
1、是指试图获得锁的线程不会堵塞，而是通过循环获得锁。
2、优点：减少上下文切换的消耗。
缺点：循环消耗CPU。
实例
public class ReentrantSpinLock {
private AtomicReference<Thread> owner = new AtomicReference<>();
// 可重入次数
private int count = 0;
// 加锁
public void lock() {
Thread current = Thread.currentThread();
if (owner.get() == current) {
count++;
return;
}
while (!owner.compareAndSet(null, current)) {
System.out.println("--我在自旋--");
}
}
//解锁
public void unLock() {
Thread current = Thread.currentThread();
//只有持有锁的线程才能解锁
if (owner.get() == current) {
if (count > 0) {
count--;
} else {
//此处无需CAS操作，因为没有竞争，因为只有线程持有者才能解锁
owner.set(null);
}
}
}
public static void main(String[] args) {
ReentrantSpinLock spinLock = new ReentrantSpinLock();
Runnable runnable = () -> {
System.out.println(Thread.currentThread().getName() + "开始尝试获取自旋锁");
spinLock.lock();
try {
System.out.println(Thread.currentThread().getName() + "获取到了自旋锁");
Thread.sleep(4000);
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
spinLock.unLock();
System.out.println(Thread.currentThread().getName() + "释放了了自旋锁");
}
};
Thread thread1 = new Thread(runnable);
Thread thread2 = new Thread(runnable);
thread1.start();
thread2.start();
}
}以上是java怎么实现可重入的自旋锁的详细内容。更多信息请关注PHP中文网其他相关文章！
