• 分布式锁和同步器
    • TOC
    • Lock"> Lock
    • Fair Lock"> Fair Lock
    • MultiLock"> MultiLock
    • ReadWriteLock"> ReadWriteLock
    • Semaphore"> Semaphore
    • CountDownLatch"> CountDownLatch

    分布式锁和同步器

    TOC

    Lock

    Redisson 分布式可重入锁，实现了 java.util.concurrent.locks.Lock 接口并支持 TTL。

    1. RLock lock = redisson.getLock("anyLock");
    2. // Most familiar locking method
    3. lock.lock();
    5. // Lock time-to-live support
    6. // releases lock automatically after 10 seconds
    7. // if unlock method not invoked
    8. lock.lock(10, TimeUnit.SECONDS);
    10. // Wait for 100 seconds and automatically unlock it after 10 seconds
    11. boolean res = lock.tryLock(100, 10, TimeUnit.SECONDS);
    12. ...
    13. lock.unlock();

    Redisson 也支持 Lock 对象的异步方法：

    1. RLock lock = redisson.getLock("anyLock");
    2. lock.lockAsync();
    3. lock.lockAsync(10, TimeUnit.SECONDS);
    4. Future<Boolean> res = lock.tryLockAsync(100, 10, TimeUnit.SECONDS);

    Fair Lock

    Redisson 分布式可重入公平锁，实现了 java.util.concurrent.locks.Lock 接口并支持 TTL， 并且保证 Redisson 客户端线程将以其请求的顺序获得锁。 它和简单的 Lock 对象有相同的接口。

    1. RLock fairLock = redisson.getFairLock("anyLock");
    2. // Most familiar locking method
    3. fairLock.lock();
    5. // Lock time-to-live support
    6. // releases lock automatically after 10 seconds
    7. // if unlock method not invoked
    8. fairLock.lock(10, TimeUnit.SECONDS);
    10. // Wait for 100 seconds and automatically unlock it after 10 seconds
    11. boolean res = fairLock.tryLock(100, 10, TimeUnit.SECONDS);
    12. ...
    13. fairLock.unlock();

    Redisson 也支持公平锁对象的异步方法：

    1. RLock fairLock = redisson.getFairLock("anyLock");
    2. fairLock.lockAsync();
    3. fairLock.lockAsync(10, TimeUnit.SECONDS);
    4. Future<Boolean> res = fairLock.tryLockAsync(100, 10, TimeUnit.SECONDS);

    MultiLock

    RedissonMultiLock 对象可用于实现 Redlock 锁算法。 它将多个 RLock 对象划为一组并且将它们当作一个锁来处理。 每个 RLock 对象可以属于不同的 Redisson 实例。

    1. RLock lock1 = redissonInstance1.getLock("lock1");
    2. RLock lock2 = redissonInstance2.getLock("lock2");
    3. RLock lock3 = redissonInstance3.getLock("lock3");
    5. RedissonMultiLock lock = new RedissonMultiLock(lock1, lock2, lock3);
    6. // locks: lock1 lock2 lock3
    7. lock.lock();
    8. ...
    9. lock.unlock();

    ReadWriteLock

    Redisson 分布式可重入 ReadWriteLock 对象，实现了 java.util.concurrent.locks.ReadWriteLock 接口并支持 TTL。 可以同时存在多个 ReadLock 拥有者，但仅允许有一个 WriteLock

    1. RReadWriteLock rwlock = redisson.getLock("anyRWLock");
    2. // Most familiar locking method
    3. rwlock.readLock().lock();
    4. // or
    5. rwlock.writeLock().lock();
    7. // Lock time-to-live support
    8. // releases lock automatically after 10 seconds
    9. // if unlock method not invoked
    10. rwlock.readLock().lock(10, TimeUnit.SECONDS);
    11. // or
    12. rwlock.writeLock().lock(10, TimeUnit.SECONDS);
    14. // Wait for 100 seconds and automatically unlock it after 10 seconds
    15. boolean res = rwlock.readLock().tryLock(100, 10, TimeUnit.SECONDS);
    16. // or
    17. boolean res = rwlock.writeLock().tryLock(100, 10, TimeUnit.SECONDS);
    18. ...
    19. lock.unlock();

    Semaphore

    Redisson 分布式 Semaphore 对象，类似于 java.util.concurrent.Semaphore 对象。

    1. RSemaphore semaphore = redisson.getSemaphore("semaphore");
    2. semaphore.acquire();
    3. //or
    4. semaphore.acquireAsync();
    5. semaphore.acquire(23);
    6. semaphore.tryAcquire();
    7. //or
    8. semaphore.tryAcquireAsync();
    9. semaphore.tryAcquire(23, TimeUnit.SECONDS);
    10. //or
    11. semaphore.tryAcquireAsync(23, TimeUnit.SECONDS);
    12. semaphore.release(10);
    13. semaphore.release();
    14. //or
    15. semaphore.releaseAsync();

    CountDownLatch

    Redisson 分布式 CountDownLatch 对象，结构类似于 java.util.concurrent.CountDownLatch 对象。

    1. RCountDownLatch latch = redisson.getCountDownLatch("anyCountDownLatch");
    2. latch.trySetCount(1);
    3. latch.await();
    5. // in other thread or other JVM
    6. RCountDownLatch latch = redisson.getCountDownLatch("anyCountDownLatch");
    7. latch.countDown();