分布式鎖用Redis好？還是Zookeeper好？

//基于jedis和lua腳本來(lái)實(shí)現(xiàn)
privatestaticfinal?String?LOCK_SUCCESS?=?"OK";
privatestaticfinal?Long?RELEASE_SUCCESS?=?1L;
privatestaticfinal?String?SET_IF_NOT_EXIST?=?"NX";
privatestaticfinal?String?SET_WITH_EXPIRE_TIME?=?"PX";

@Override
public?String?acquire()?{
????try?{
????????//?獲取鎖的超時(shí)時(shí)間，超過這個(gè)時(shí)間則放棄獲取鎖
????????long?end?=?System.currentTimeMillis()?+?acquireTimeout;
????????//?隨機(jī)生成一個(gè)?value
????????String?requireToken?=?UUID.randomUUID().toString();
????????while?(System.currentTimeMillis()?????????????String?result?=?jedis
????????????????.set(lockKey,?requireToken,?SET_IF_NOT_EXIST,?SET_WITH_EXPIRE_TIME,?expireTime);
????????????if?(LOCK_SUCCESS.equals(result))?{
????????????????return?requireToken;
????????????}
????????????try?{
????????????????Thread.sleep(100);
????????????}?catch?(InterruptedException?e)?{
????????????????Thread.currentThread().interrupt();
????????????}
????????}
????}?catch?(Exception?e)?{
????????log.error("acquire?lock?due?to?error",?e);
????}

????returnnull;
}

@Override
public?boolean?release(String?identify)?{
????if?(identify?==?null)?{
????????returnfalse;
????}
????//通過lua腳本進(jìn)行比對(duì)刪除操作，保證原子性
????String?script?=?"if?redis.call('get',?KEYS[1])?==?ARGV[1]?then?return?redis.call('del',?KEYS[1])?else?return?0?end";
????Object?result?=?new?Object();
????try?{
????????result?=?jedis.eval(script,?Collections.singletonList(lockKey),
????????????Collections.singletonList(identify));
????????if?(RELEASE_SUCCESS.equals(result))?{
????????????log.info("release?lock?success,?requestToken:{}",?identify);
????????????returntrue;
????????}
????}?catch?(Exception?e)?{
????????log.error("release?lock?due?to?error",?e);
????}?finally?{
????????if?(jedis?!=?null)?{
????????????jedis.close();
????????}
????}

????log.info("release?lock?failed,?requestToken:{},?result:{}",?identify,?result);
????returnfalse;
}

<dependency>
????<groupId>org.redissongroupId>
????<artifactId>redissonartifactId>
????<version>3.13.4version>
dependency>

private?void?test()?{
????//分布式鎖名??鎖的粒度越細(xì)，性能越好
????RLock?lock?=?redissonClient.getLock("test_lock");
????lock.lock();
????try?{
????????//具體業(yè)務(wù)......
????}?finally?{
????????lock.unlock();
????}
}

//?最常見的使用方法
lock.lock();

//?加鎖以后10秒鐘自動(dòng)解鎖
//?無(wú)需調(diào)用unlock方法手動(dòng)解鎖
lock.lock(10,?TimeUnit.SECONDS);

public?void?test()?{
????RLock?lock?=?redissonClient.getLock("test_lock");
????lock.lock(30,?TimeUnit.SECONDS);
????try?{
????????//.......具體業(yè)務(wù)
????}?finally?{
????????//手動(dòng)釋放鎖
????????lock.unlock();
????}
}

public?class?ZooKeeperDistributedLock?implements?Watcher?{

????private?ZooKeeper?zk;
????private?String?locksRoot?=?"/locks";
????private?String?productId;
????private?String?waitNode;
????private?String?lockNode;
????private?CountDownLatch?latch;
????private?CountDownLatch?connectedLatch?=?new?CountDownLatch(1);
????private?int?sessionTimeout?=?30000;

????public?ZooKeeperDistributedLock(String?productId)?{
????????this.productId?=?productId;
????????try?{
????????????String?address?=?"192.168.189.131:2181,192.168.189.132:2181";
????????????zk?=?new?ZooKeeper(address,?sessionTimeout,?this);
????????????connectedLatch.await();
????????}?catch?(IOException?e)?{
????????????throw?new?LockException(e);
????????}?catch?(KeeperException?e)?{
????????????throw?new?LockException(e);
????????}?catch?(InterruptedException?e)?{
????????????throw?new?LockException(e);
????????}
????}

????public?void?process(WatchedEvent?event)?{
????????if?(event.getState()?==?KeeperState.SyncConnected)?{
????????????connectedLatch.countDown();
????????????return;
????????}

????????if?(this.latch?!=?null)?{
????????????this.latch.countDown();
????????}
????}

????public?void?acquireDistributedLock()?{
????????try?{
????????????if?(this.tryLock())?{
????????????????return;
????????????}?else?{
????????????????waitForLock(waitNode,?sessionTimeout);
????????????}
????????}?catch?(KeeperException?e)?{
????????????throw?new?LockException(e);
????????}?catch?(InterruptedException?e)?{
????????????throw?new?LockException(e);
????????}
????}
????//獲取鎖
????public?boolean?tryLock()?{
????????try?{
????????//?傳入進(jìn)去的locksRoot?+?“/”?+?productId
????????//?假設(shè)productId代表了一個(gè)商品id，比如說(shuō)1
????????//?locksRoot?=?locks
????????//?/locks/10000000000，/locks/10000000001，/locks/10000000002
????????lockNode?=?zk.create(locksRoot?+?"/"?+?productId,?new?byte[0],?ZooDefs.Ids.OPEN_ACL_UNSAFE,?CreateMode.EPHEMERAL_SEQUENTIAL);

????????//?看看剛創(chuàng)建的節(jié)點(diǎn)是不是最小的節(jié)點(diǎn)
????????// locks：10000000000，10000000001，10000000002
????????List?locks?=?zk.getChildren(locksRoot,?false);
????????Collections.sort(locks);

????????if(lockNode.equals(locksRoot+"/"+?locks.get(0))){
????????????//如果是最小的節(jié)點(diǎn),則表示取得鎖
????????????return?true;
????????}

????????//如果不是最小的節(jié)點(diǎn)，找到比自己小1的節(jié)點(diǎn)
??????int?previousLockIndex?=?-1;
????????????for(int?i?=?0;?i?????????if(lockNode.equals(locksRoot?+?“/”?+?locks.get(i)))?{
????????????????????previousLockIndex?=?i?-?1;
????????????break;
????????}
???????}

???????this.waitNode?=?locks.get(previousLockIndex);
????????}?catch?(KeeperException?e)?{
????????????throw?new?LockException(e);
????????}?catch?(InterruptedException?e)?{
????????????throw?new?LockException(e);
????????}
????????return?false;
????}

????private?boolean?waitForLock(String?waitNode,?long?waitTime)?throws?InterruptedException,?KeeperException?{
????????Stat?stat?=?zk.exists(locksRoot?+?"/"?+?waitNode,?true);
????????if?(stat?!=?null)?{
????????????this.latch?=?new?CountDownLatch(1);
????????????this.latch.await(waitTime,?TimeUnit.MILLISECONDS);
????????????this.latch?=?null;
????????}
????????return?true;
????}

????//釋放鎖
????public?void?unlock()?{
????????try?{
????????????System.out.println("unlock?"?+?lockNode);
????????????zk.delete(lockNode,?-1);
????????????lockNode?=?null;
????????????zk.close();
????????}?catch?(InterruptedException?e)?{
????????????e.printStackTrace();
????????}?catch?(KeeperException?e)?{
????????????e.printStackTrace();
????????}
????}
????//異常
????public?class?LockException?extends?RuntimeException?{
????????private?static?final?long?serialVersionUID?=?1L;

????????public?LockException(String?e)?{
????????????super(e);
????????}

????????public?LockException(Exception?e)?{
????????????super(e);
????????}
????}
}