基于Redis实现分布式锁，Redisson使用及源码分析

本是古典何须时尚 2022-05-31 10:25 212阅读 0赞

[http://blog.jobbole.com/99751/][http_blog.jobbole.com_99751]

在分布式场景下，有很多种情况都需要实现最终一致性。在设计远程上下文的领域事件的时候，为了保证最终一致性，在通过领域事件进行通讯的方式中，可以共享存储（领域模型和消息的持久化数据源），或者做全局XA事务（两阶段提交，数据源可分开），也可以借助消息中间件（消费者处理需要能幂等）。通过Observer模式来发布领域事件可以提供很好的高并发性能，并且事件存储也能追溯更小粒度的事件数据，使各个应用系统拥有更好的自治性。

本文主要探讨另外一种实现分布式最终一致性的解决方案——采用分布式锁。基于分布式锁的解决方案，比如zookeeper,redis都是相较于持久化（如利用InnoDB行锁，或事务，或version乐观锁）方案提供了高可用性，并且支持丰富化的使用场景。 本文通过Java版本的redis分布式锁开源框架——Redisson来解析一下实现分布式锁的思路。

# 分布式锁的使用场景 #

如果是不跨限界上下文的情况，跟本地领域服务相关的数据一致性，尽量还是用事务来保证。但也有些无法用事务或者乐观锁来处理的情况，这些情况大多是对于一个共享型的数据源，有并发写操作的场景，但又不是对于单一领域的操作。

举个例子，还是用租书来比喻,A和B两个人都来租书，在查看图书的时候，发现自己想要看的书《大设计》库存仅剩一本。书店系统中，书作为一种商品，是在商品系统中，以Item表示出租商品的领域模型，同时每一笔交易都会产生一个订单，Order是在订单系统（交易限界上下文）中的领域模型。这里假设先不考虑跨系统通信的问题（感兴趣的可以参考下[领域服务、领域事件][Link 1]），也暂时不考虑支付环节，但是我们需要保证A,B两个人不会都对于《大设计》产生订单就可以，也就是其中一个人是可以成功下单，另外一个人只要提示库存已没即可。此时，书的库存就是一种共享的分布式资源，下订单，减库存就是一个需要保证一致性的写操作。但又因为两个操作不能在同一个本地事务，或者说，不共享持久化的数据源的情况，这时候就可以考虑用分布式锁来实现。本例子中，就需要对于共享资源——书的库存进行加锁，至于锁的key可以结合领域模型的唯一标识，如itemId,以及操作类型（如操作类型是RENT的）设计一个待加锁的资源标识。当然，这里还有一个并发性能的问题，如果是个库存很多的秒杀类型的业务，那么就不能单纯在itemId 加类型加锁，还需要设计排队队列以及合理的调度算法，防止超卖等等，那些就是题外话了。本文只是将这个场景作为一个切入点，具体怎么设计锁，什么场景用还要结合业务。

# 需要解决的问题 #

分布式的思路和线程同步锁ReentrantLock的思路是一样的。我们也要考虑如以下几个问题：

*  死锁的情况。复杂的网络环境下，当加锁成功，后续操作正在处理时，获得锁的节点忽然宕机，无法释放锁的情况。如A在Node1 节点申请到了锁资源，但是Node1宕机，锁一直无法释放，订单没有生成，但是其他用户将无法申请到锁资源。
 *  锁的性能效率。分布式锁不能成为性能瓶颈或者单点故障不能导致业务异常。
 *  如果关键业务，可能需要重入场景，是否设计成可重入锁。这个可以参考下在多线程的情况下，比如ReentrantLock就是一种可重入锁，其内部又提供了公平锁和非公平锁两种实现和应用，本文不继续探讨。带着以上问题，和场景，沿着下文，来一一找到解决方案。

# 基于Redis实现 #

## Redis 命令 ##

在Redisson介绍前，回顾下Redis的命令，以及不通过任何开源框架，可以基于redis怎么设计一个分布式锁。基于不同应用系统实现的语言，也可以通过其他一些如Jedis,或者Spring的RedisOperations 等，来执行Reids命令[Redis command list][]。

分布式锁主要需要以下redis命令，这里列举一下。在实现部分可以继续参照命令的操作含义。

1.  SETNX key value (SET if Not eXists):当且仅当 key 不存在，将 key 的值设为 value ，并返回1；若给定的 key 已经存在，则 SETNX 不做任何动作，并返回0。详见：[SETNX commond][]
2.  GETSET key value:将给定 key 的值设为 value ，并返回 key 的旧值 (old value)，当 key 存在但不是字符串类型时，返回一个错误，当key不存在时，返回nil。详见：[GETSET commond][]
3.  GET key:返回 key 所关联的字符串值，如果 key 不存在那么返回 nil 。详见：[GET Commond][]
4.  DEL key \[KEY …\]:删除给定的一个或多个 key ,不存在的 key 会被忽略,返回实际删除的key的个数（integer）。详见：[DEL Commond][]
5.  HSET key field value：给一个key 设置一个\{field=value\}的组合值，如果key没有就直接赋值并返回1，如果field已有，那么就更新value的值，并返回0.详见：[HSET Commond][]
6.  HEXISTS key field:当key 中存储着field的时候返回1，如果key或者field至少有一个不存在返回0。详见[HEXISTS Commond][]
7.  HINCRBY key field increment:将存储在 key 中的哈希（Hash）对象中的指定字段 field 的值加上增量 increment。如果键 key 不存在，一个保存了哈希对象的新建将被创建。如果字段 field 不存在，在进行当前操作前，其将被创建，且对应的值被置为 0。返回值是增量之后的值。详见：[HINCRBY Commond][]
8.  PEXPIRE key milliseconds：设置存活时间，单位是毫秒。expire操作单位是秒。详见:[PEXPIRE Commond][]
9.  PUBLISH channel message:向channel post一个message内容的消息，返回接收消息的客户端数。详见[PUBLISH Commond][]

## Redis 实现分布式锁 ##

假设我们现在要给itemId 1234 和下单操作 OP\_ORDER 加锁，key是OP\_ORDER\_1234,结合上面的redis命令，似乎加锁的时候只要一个SETNX OP\_ORDER\_1234 currentTimestamp ，如果返回1代表加锁成功，返回0 表示锁被占用着。然后再用DEL OP\_ORDER\_1234解锁，返回1表示解锁成功，0表示已经被解锁过。然而却还存在着很多问题：SETNX会存在锁竞争，如果在执行过程中客户端宕机，也会引起死锁问题，即锁资源无法释放。并且当一个资源解锁的时候，释放锁之后，其他之前等待的锁没有办法再次自动重试申请锁（除非重新申请锁）。解决死锁的问题其实可以可以向Mysql的死锁检测学习，设置一个失效时间，通过key的时间戳来判断是否需要强制解锁。但是强制解锁也存在问题，一个就是时间差问题，不同的机器的本地时间可能也存在时间差，在很小事务粒度的高并发场景下还是会存在问题，比如删除锁的时候，在判断时间戳已经超过时效，有可能删除了其他已经获取锁的客户端的锁。另外，如果设置了一个超时时间，但是确实执行时间超过了超时时间，那么锁会被自动释放，原来持锁的客户端再次解锁的时候会出现问题，而且最为严重的还是一致性没有得到保障。

所以设计的时候需要考虑以下几点：

1.  锁的时效设置。避免单点故障造成死锁，影响其他客户端获取锁。但是也要保证一旦一个客户端持锁，在客户端可用时不会被其他客户端解锁。（网上很多解决方案都是其他客户端等待队列长度判断是否强制解锁，但其实在偶发情况下就不能保证一致性，也就失去了分布式锁的意义）。
2.  持锁期间的check,尽量在关键节点检查锁的状态，所以要设计成可重入锁，但在客户端使用时要做好吞吐量的权衡。
3.  减少获取锁的操作，尽量减少redis压力。所以需要让客户端的申请锁有一个等待时间，而不是所有申请锁的请求要循环申请锁。
4.  加锁的事务或者操作尽量粒度小，减少其他客户端申请锁的等待时间，提高处理效率和并发性。
5.  持锁的客户端解锁后，要能通知到其他等待锁的节点，否则其他节点只能一直等待一个预计的时间再触发申请锁。类似线程的notifyAll,要能同步锁状态给其他客户端，并且是分布式消息。
6.  考虑任何执行句柄中可能出现的异常，状态的正确流转和处理。比如，不能因为一个节点解锁失败，或者锁查询失败（redis 超时或者其他运行时异常），影响整个等待的任务队列，或者任务池。

### 锁设计 ###

由于时间戳的设计有很多问题，以及上述几个问题，所以再换一种思路。先回顾几个关于锁的概念和经典java API。通过一些java.util.concurrent的API来处理一些本地队列的同步以及等待信号量的处理。

*  Semaphore :Semaphore可以控制某个资源可被同时访问的个数，通过 acquire() 获取一个许可，如果没有就等待，而 release() 释放一个许可。其内部维护了一个int 类型的permits。有一个关于厕所的比喻很贴切，10个人在厕所外面排队，厕所有5个坑，只能最多进去五个人，那么就是初始化一个 permits=5的Semaphore。当一个人出来，会release一个坑位，其他等坑的人会被唤醒然后开始要有人进坑。Semaphore同ReentrantLock一样都是基于AbstractQueuedSynchronizer提供了公平锁和非公平锁两种实现。如果等待的人有秩序的排队等着，就说明选择了Semaphore的公平锁实现，如果外面的人没有秩序，谁抢到是谁的（活跃线程就会一直有机会，存在线程饥饿可能），那就是Semaphore的非公平锁实现。无论外面人怎么个等法Semaphore对于出坑的控制是一致的，每次只能是从一个坑里出来一个人。理解起来，其实就是厕所的5个坑位是一个共享资源，也就是permits的值=5,每次acquire一下就是外面来了个人排队，每次release一下就是里面出来个人。厕所聊多有点不雅观，再回归到分布式锁的话题。在刚才讲述的redis实现分布式锁的“第三点”，减少redis申请锁调用频率上就可以通过Semaphore来控制请求。虽然Semaphore只是虚拟机内部的锁粒度的实现（不能跨进程），但是也可以一定程度减轻最后请求redis节点的压力。当然，也有种方法是，随机sleep一段时间再去tryLock之类的，也可以达到减轻最后redis节点压力，但是毕竟使用信号量能更好得控制。而且我们可以再简单点，对于同一个锁对象的申请锁操作，可以设计一个初始化permits = 0的LockEntry,permits = 0也就顾名思义，谁都进不来，厕所维修中。当有一个持锁对象unlock的时候，通过分布式消息机制通知所有等待节点，这时候，再release，这时候permits=1，也就是本虚拟机中只能有一个线程能在acquire（）的阻塞中脱颖而出（当然只是进了坑，但不一定能获取得到分布式锁）。
 *  ConcurrentHashMap:这个应该不必多说，之谈谈在设计分布式锁中的用途。在上述的“第一点”，对于锁的时效性的设置里提到了，要在持锁线程正常运行（持锁节点没有宕机或内部异常）的时候，保证其一直占用锁。只要占着茅坑的人还在用着，只要他还没有暴毙或者无聊占着茅坑不XX,那就应该让外面的人都等着，不能强行开门托人。再收回来。。。这里ConcurrentHashMap的key无疑是锁对象的标识（我们需要设计的redis的key），value就是一个时间任务对象，比如可以netty的TimerTask或其他定时API，定时得触发给我的锁重新设置延时。这就是好比（好吧，再次用厕所比喻），蹲在里面的人的一种主动行为，隔1分钟敲两下厕所门，让外面的等的人知道，里面的人正在使用中，如果里面的人1分钟超过还没有敲门，可能是里面人挂掉了，那么再采取强制措施，直接开门拽人，释放坑位。

并发API以及一些框架的使用主要是控制锁的进入和调度，加锁的流程以及锁的逻辑也是非常重要。因为redis支持hash结构，除了key作为锁的标识，还可以利用value的结构

### 加锁 ###

下面参数的含义先说明下 :

*  KEYS\[1\] ：需要加锁的key，这里需要是字符串类型。
 *  ARGV\[1\] ：锁的超时时间，防止死锁
 *  ARGV\[2\] ：锁的唯一标识，也就是刚才介绍的 id（UUID.randomUUID()） + “:” + threadId

Java

以上的方法，当返回空是，说明获取到锁，如果返回一个long数值（pttl 命令的返回值），说明锁已被占用，通过返回剩余时间，外部可以做一些等待时间的判断和调整。

### 解锁 ###

也还是先说明一下参数信息：

– KEYS\[1\] ：需要加锁的key，这里需要是字符串类型。

– KEYS\[2\] ：redis消息的ChannelName,一个分布式锁对应唯一的一个channelName:“redisson\_lock\_\_channel\_\_\{” + getName() + “\}”

– ARGV\[1\] ：reids消息体，这里只需要一个字节的标记就可以，主要标记redis的key已经解锁，再结合redis的Subscribe，能唤醒其他订阅解锁消息的客户端线程申请锁。

– ARGV\[2\] ：锁的超时时间，防止死锁

– ARGV\[3\] ：锁的唯一标识，也就是刚才介绍的 id（UUID.randomUUID()） + “:” + threadId

Java

这就是解锁过程，当然建议提供强制解锁的接口，直接删除key，以防一些紧急故障出现的时候，关键业务节点受到影响。这里还有一个关键点，就是publish命令，通过在锁的唯一通道发布解锁消息，可以减少其他分布式节点的等待或者空转，整体上能提高加锁效率。至于redis的消息订阅可以有多种方式，基于Jedis的订阅API或者Spring的MessageListener都可以实现订阅，这里就可以结合刚才说的Semaphore,在第一次申请锁失败后acquire,接收到分布式消息后release就可以控制申请锁流程的再次进入。下面结合Redisson源码，相信会有更清晰的认识。

# 使用Redisson示例 #

Redisson使用起来很方便，但是需要redis环境支持eval命令，否则一切都是悲剧，比如me.结果还是要用RedisCommands去写一套。例子就如下，获得一个RLock锁对象，然后tryLock 和unlock。trylock方法提供了锁重入的实现，并且客户端一旦持有锁，就会在能正常运行期间一直持有锁，直到主动unlock或者节点故障，主动失效（超过默认的过期时间）释放锁。

Java

Redisson还提供了设置最长等待时间以及设置释放锁时间的含参tryLock接口 boolean tryLock(long waitTime, long leaseTime, TimeUnit unit) throws InterruptedException; 。Redisson的lock 扩展了java.util.concurrent.locks.Lock的实现，也基本按照了Lock接口的实现方案。lock（）方法会一直阻塞申请锁资源，直到有可用的锁释放。下面一部分会详细解析一部分关键实现的代码。

# Redisson源码解析 #

Redisson 的异步任务(Future,Promise，FutureListener API)，任务计时器(Timeout，TimerTask)，以及通过AbstractChannel连接redis以及写入执行批处理命令等很多都是基于netty框架的。po主因为不能使用eval,所以用Spring提供的redisApi ,RedisOperations来处理redis指令，异步调度等用了Spring的AsyncResult，MessageListener以及一些concurrent api。这里还是先看一下Redisson的实现。

## trylock ##

这里以带参数的trylock解析一下，无参的trylock是一种默认参数的实现。先源码走读一下。

Java

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     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       13 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       14 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       15 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       16 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       17 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       18 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       19 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       20 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       21 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       22 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       23 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       24 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       25 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       26 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       27 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       28 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       29 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       30 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       31 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       32 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       33 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       34 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       35 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       36 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       37 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       38 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       39 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       40 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       41 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       42 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       43 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       44 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       45 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       46 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       47 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       48 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       49 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       50 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       51 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       52 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       53 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       54 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       55 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       56 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       57 
     </div> 
     <div style="border-top:none;border-right:1px solid rgb(222,222,222);border-bottom:none;border-left:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;text-align:right;height:inherit;min-width:1.2em;color:rgb(170,170,170);">
       58 
     </div> 
    </div></td> 
   <td style="font-size:13px;text-align:center;width:1334px;background:none;border-style:none;margin:0px;padding:0px;vertical-align:top;font-family:Monaco, MonacoRegular, 'Courier New', monospace;"> 
    <div style="margin:0px;padding-right:0px;padding-left:0px;text-align:left;color:rgb(0,0,0);white-space:pre;border:none;padding-top:5px;padding-bottom:3px;background:none;line-height:15px;"> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-style:italic;color:rgb(102,102,102);">@Override</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(128,0,128);">public</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">boolean</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">tryLock</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">long</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">waitTime</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">,</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">long</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">leaseTime</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">,</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">TimeUnit </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">unit</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(128,0,128);">throws</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">InterruptedException</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">{ </span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">long</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">time</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">=</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">unit</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">toMillis</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">waitTime</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 申请锁，返回还剩余的锁过期时间</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">Long</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">ttl</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">=</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">tryAcquire</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">leaseTime</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">,</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">unit</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 如果为空，表示申请锁成功</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">if</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">ttl</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">==</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">null</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">{ </span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">return</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">true</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">}</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 订阅监听redis消息，并且创建RedissonLockEntry，其中RedissonLockEntry中比较关键的是一个 Semaphore属性对象用来控制本地的锁请求的信号量同步，返回的是netty框架的Future实现。</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">Future </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">future</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">=</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">subscribe</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 阻塞等待subscribe的future的结果对象，如果subscribe方法调用超过了time，说明已经超过了客户端设置的最大wait time，则直接返回false，取消订阅，不再继续申请锁了。</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">if</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">!</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">future</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">await</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">time</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">,</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">TimeUnit</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">MILLISECONDS</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">{ </span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">future</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">addListener</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">new</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">FutureListener</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">{ </span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-style:italic;color:rgb(102,102,102);">@Override</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(128,0,128);">public</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">void</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">operationComplete</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">Future </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">future</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(128,0,128);">throws</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">Exception</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">{ </span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">if</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">future</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">isSuccess</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">{ </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">unsubscribe</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">future</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">}</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">}</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">}</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">return</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">false</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">}</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;">
       &nbsp; 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">try</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">{ </span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">while</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">true</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">{ </span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 再次尝试一次申请锁</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">ttl</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">=</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">tryAcquire</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">leaseTime</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">,</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">unit</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 获得锁，返回</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">if</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">ttl</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">==</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">null</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">{ </span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">return</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">true</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">}</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 不等待申请锁，返回</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">if</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;">time</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,153,153);">0</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">{ </span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">return</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">false</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">}</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;">
       &nbsp; 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 阻塞等待锁</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">long</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">current</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">=</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">System</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">currentTimeMillis</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">RedissonLockEntry </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">entry</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">=</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">getEntry</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;">
       &nbsp; 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">if</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">ttl</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&gt;=</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,153,153);">0</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&amp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">ttl</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 通过信号量(共享锁)阻塞,等待解锁消息.</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 如果剩余时间(ttl)小于wait time ,就在 ttl 时间内，从Entry的信号量获取一个许可(除非被中断或者一直没有可用的许可)。</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 否则就在wait time 时间范围内等待可以通过信号量</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">entry</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">getLatch</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">tryAcquire</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">ttl</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">,</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">TimeUnit</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">MILLISECONDS</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">}</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;">else</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">{ </span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">entry</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">getLatch</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:#008080;">tryAcquire</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">(</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">time</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">,</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">TimeUnit</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">.</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">MILLISECONDS</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">)</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">;</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(51,51,51);">}</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(153,153,153);font-style:italic;">// 更新等待时间(最大等待时间-已经消耗的阻塞时间)</span> 
     </div> 
     <div style="border:none;margin:0px;padding:0px 5px;font-family:inherit;background:none;height:inherit;"> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;font-weight:bold;color:rgb(128,0,128);">long</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,45,122);">elapsed</span> 
      <span style="border:0px;margin:0px;padding:0px;font-family:inherit;height:inherit;color:rgb(0,111,224);"> </span> 
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  </tr> 
 </tbody> 
</table>

上述方法，调用加锁的逻辑就是在tryAcquire(long leaseTime, TimeUnit unit)中

Java

tryAcquire(long leaseTime, TimeUnit unit)只是针对leaseTime的不同参数进行不同的转发处理，再提一下，trylock的无参方法就是直接调用了get(tryLockInnerAsync(Thread.currentThread().getId()));

所以下面再看核心的tryLockInnerAsync 基本命令已经在之前解析过，相信这里看起来应该比较轻松，返回的是一个future对象，是为了异步处理IO，提高系统吞吐量。

Java

再说明一下，tryLock(long waitTime, long leaseTime, TimeUnit unit)有leaseTime参数的申请锁方法是会按照leaseTime时间来自动释放锁的。但是没有leaseTime参数的，比如tryLock()或者tryLock(long waitTime, TimeUnit unit)以及lock()是会一直持有锁的。再来看一下没有leaseTime参数的tryLockInnerAsync(Thread.currentThread().getId())

Java

这里比有leaseTime参数的trylock就多了异步scheduleExpirationRenewal调度。可以继续看一下,这里的expirationRenewalMap就是之前降到的一个ConcurrentMap结构。下面的这个调度方式很精妙。除非被unlock的cancleTask方法触发，否则会一直循环重置过期时间。

Java

这个任务，其实还有一个问题，个人觉得在expirationRenewalMap.containsKey判断时也加上isLocked判断会比较好，以防止unlock时出现redis节点异常的时候，任务没有办法自动停止，或者设置一个最大执行次数的限制也可以，否则极端情况下也会耗尽本地节点的CPU资源。

## unlock ##

解锁的逻辑相对简单，如下，redis 命令相信看起来也会比较轻松了。

Java

这里的 cancelExpirationRenewal对应着取消 scheduleExpirationRenewal的重置expire时间任务。

Java

再看一下Redisson是如何处理unlock的redis消息的。这里的消息内容就是unlockMessage = 0L和unlock方法中publish的内容是对应的。

Java

Redisson还支持Redis的多种集群配置，一主一备，一主多备，单机等等。也是通过netty的EventExecutorGroup，Promise，Future等API实现调度的。

# 结语 #

在思考是否采用分布式锁以及采用哪种实现方案的时候，还是要基于业务，技术方案一定是基于业务基础，服务于业务，并且衡量过投入产出比的。所以如果有成熟的解决方案，在业务可承受规模肯定是不要重复造轮子，当然还要经过严谨的测试。在po主用Spring的redis api实现时，也遇到了一些问题。

比如hIncrBy 的字符集问题，在使用命令的时候，当然可以直接set a 1然后incr a 1，这个问题可以参考[ERR value is not an integer or out of range 问题][ERR value is not an integer or out of range]，但在使用RedisConnection的时候，需要通过转码，byte\[\] value =SafeEncoder.encode(String.valueOf(“1”)) 再 connection.hSet(key, field, value)这样才可以，或者自己通过String转成正确的编码也可以。

还有刚才说的调度pexpire任务，在unlock异常的时候，任务池中的任务无法自动结束。另外就是Spring的MessageListener的onMessage(Message message, byte\[\] pattern)回调方法message.getBody()是byte数组，消息内容转化的时候要处理一下。

## 资源 ##

*  [领域服务、领域事件][Link 1]
 *  [几种并发锁性能对比][Link 2]
 *  [ERR value is not an integer or out of range 问题][ERR value is not an integer or out of range]
 *  [Redis 命令查询][Redis]
 *  [Redisson github][]

[http_blog.jobbole.com_99751]: http://blog.jobbole.com/99751/
[Link 1]: http://blog.csdn.net/lijingyao8206/article/details/50867008
[Redis command list]: https://github.com/antirez/redis/blob/93e7a130fc9594e41ccfc996b5eca7626ae5356a/src/redis.c#L119
[SETNX commond]: http://redis.io/commands/setnx
[GETSET commond]: http://redis.io/commands/GETSET
[GET Commond]: http://redis.io/commands/get
[DEL Commond]: http://redis.io/commands/del
[HSET Commond]: http://redis.io/commands/HSET
[HEXISTS Commond]: http://redis.io/commands/hexists
[HINCRBY Commond]: http://redis.io/commands/HINCRBY
[PEXPIRE Commond]: http://redis.io/commands/pexpire
[PUBLISH Commond]: http://redis.io/commands/publish
[ERR value is not an integer or out of range]: http://www.hydrogen18.com/blog/first-impression-redis.html
[Link 2]: http://baptiste-wicht.com/posts/2010/09/java-synchronization-mutual-exclusion-benchmark.html
[Redis]: http://redis.io/commands
[Redisson github]: https://github.com/mrniko/redisson