Java并发编程七CAS自旋锁

  • Z时代
  • 2024-01-10
  • 分类：综合

编程

public class CASLockUtil {
public static AtomicReference casLock = new AtomicReference<Thread>();
/**
     * 加锁
     * @param waitMillis 重试时间，如果超过这个时间则放弃当前的锁Millis
     * @return
*/
public  static boolean lock(long waitMillis){
long end = System.currentTimeMillis()+waitMillis;
        boolean  isLock = casLock.compareAndSet(null,Thread.currentThread());
        while (!isLock&&end> System.currentTimeMillis()){
            isLock = casLock.compareAndSet(null,Thread.currentThread());
}
//如果是0就无限尝试
while (waitMillis==0&&!isLock){
            isLock = casLock.compareAndSet(null,Thread.currentThread());
}
return isLock;
}
/**
     *  //解锁
     * @return
*/
public  static boolean unLock(){
boolean  isLock = casLock.compareAndSet(Thread.currentThread(),null);
        return isLock;
}
public static void main(String[] args) {
new Thread(new Runnable() {
            @Override
public void run() {
try {
boolean isLock =   CASLockUtil.lock(1000);
                    if(isLock){
                        System.out.println("线程1拿到锁休眠10秒");
Thread.sleep(10000);
}else {
                        System.out.println("线程1没有拿到锁");
}
                }catch (Exception e){
                }finally {
                    CASLockUtil.unLock();
}
            }
        }).start();
new Thread(new Runnable() {
            @Override
public void run() {
try {
boolean isLock =   CASLockUtil.lock(0);
                    if(isLock){
                        System.out.println("线程2拿到锁休眠10秒");
Thread.sleep(10000);
}else {
                        System.out.println("线程2没有拿到锁");
}
                }catch (Exception e){
                }finally {
                    CASLockUtil.unLock();
}
            }
        }).start();
}
}

利用AtomicReference的compareAndSet对当前线程对象进行加锁。测试结果

线程1拿到锁休眠10秒
线程2拿到锁休眠10秒

 

以上是 Java并发编程七CAS自旋锁 的全部内容， 来源链接： utcz.com/z/517493.html

回到顶部