自旋锁

自旋锁

• spinlock
  自定义一个锁测试

• public class SpinLockDemo {
      AtomicReference<Thread> atomicReference = new AtomicReference();
  
      //加锁
      public void myLock() {
          Thread thread = Thread.currentThread();
          System.out.println(Thread.currentThread().getName() + "MyLock");
          //自旋锁
          while (!atomicReference.compareAndSet(null, thread)) {
  
          }
      }
  
      // 解锁
      public void myUnLock() {
          Thread thread = Thread.currentThread();
          System.out.println(Thread.currentThread().getName() + "myUnLock");
          atomicReference.compareAndSet(thread, null);
      }
  }
  

• 

• public class Test01 {
      public static void main(String[] args) throws InterruptedException {
          /*ReentrantLock reentrantLock = new ReentrantLock();
          reentrantLock.lock();
          reentrantLock.unlock();*/
          // 底层使用的自旋锁CAS
          SpinLockDemo lock = new SpinLockDemo();
          new Thread(() -> {
              lock.myLock();
              try {
                  TimeUnit.SECONDS.sleep(5);
              } catch (Exception e) {
                  e.printStackTrace();
              } finally {
                  lock.myUnLock();
              }
          }, "T1").start();
          TimeUnit.SECONDS.sleep(1);
          new Thread(() -> {
              lock.myLock();
              try {
                  TimeUnit.SECONDS.sleep(1);
              } catch (Exception e) {
                  e.printStackTrace();
              } finally {
                  lock.myUnLock();
              }
          }, "T2").start();
      }
  }