分布式鎖用 Redis 還是 Zookeeper？

//?獲取鎖
//?NX是指如果key不存在就成功，key存在返回false，PX可以指定過(guò)期時(shí)間
SET?anyLock?unique_value?NX?PX?30000


//?釋放鎖：通過(guò)執(zhí)行一段lua腳本
//?釋放鎖涉及到兩條指令，這兩條指令不是原子性的
//?需要用到redis的lua腳本支持特性，redis執(zhí)行l(wèi)ua腳本是原子性的
if?redis.call("get",KEYS[1])?==?ARGV[1]?then
return?redis.call("del",KEYS[1])
else
return?0
end

Config?config?=?new?Config();
config.useClusterServers()
.addNodeAddress("redis://192.168.31.101:7001")
.addNodeAddress("redis://192.168.31.101:7002")
.addNodeAddress("redis://192.168.31.101:7003")
.addNodeAddress("redis://192.168.31.102:7001")
.addNodeAddress("redis://192.168.31.102:7002")
.addNodeAddress("redis://192.168.31.102:7003");

RedissonClient?redisson?=?Redisson.create(config);


RLock?lock?=?redisson.getLock("anyLock");
lock.lock();
lock.unlock();

//?加鎖邏輯
private??RFuture?tryAcquireAsync(long?leaseTime,?TimeUnit?unit,?final?long?threadId)?{
????if?(leaseTime?!=?-1)?{
????????return?tryLockInnerAsync(leaseTime,?unit,?threadId,?RedisCommands.EVAL_LONG);
????}
????//?調(diào)用一段lua腳本，設(shè)置一些key、過(guò)期時(shí)間
????RFuture?ttlRemainingFuture?=?tryLockInnerAsync(commandExecutor.getConnectionManager().getCfg().getLockWatchdogTimeout(),?TimeUnit.MILLISECONDS,?threadId,?RedisCommands.EVAL_LONG);
????ttlRemainingFuture.addListener(new?FutureListener()?{
????????@Override
????????public?void?operationComplete(Future?future)?throws?Exception?{
????????????if?(!future.isSuccess())?{
????????????????return;
????????????}

????????????Long?ttlRemaining?=?future.getNow();
????????????//?lock?acquired
????????????if?(ttlRemaining?==?null)?{
????????????????//?看門狗邏輯
????????????????scheduleExpirationRenewal(threadId);
????????????}
????????}
????});
????return?ttlRemainingFuture;
}


?RFuture?tryLockInnerAsync(long?leaseTime,?TimeUnit?unit,?long?threadId,?RedisStrictCommand?command)?{
????internalLockLeaseTime?=?unit.toMillis(leaseTime);

????return?commandExecutor.evalWriteAsync(getName(),?LongCodec.INSTANCE,?command,
??????????????"if?(redis.call('exists',?KEYS[1])?==?0)?then?"?+
??????????????????"redis.call('hset',?KEYS[1],?ARGV[2],?1);?"?+
??????????????????"redis.call('pexpire',?KEYS[1],?ARGV[1]);?"?+
??????????????????"return?nil;?"?+
??????????????"end;?"?+
??????????????"if?(redis.call('hexists',?KEYS[1],?ARGV[2])?==?1)?then?"?+
??????????????????"redis.call('hincrby',?KEYS[1],?ARGV[2],?1);?"?+
??????????????????"redis.call('pexpire',?KEYS[1],?ARGV[1]);?"?+
??????????????????"return?nil;?"?+
??????????????"end;?"?+
??????????????"return?redis.call('pttl',?KEYS[1]);",
????????????????Collections.