分布式锁：RedisLockRegistry和Zookeeper

RedisLockRegistry https://www.jianshu.com/p/8373d1e9f7a7

ZookeeperLockRegistry 通过zookeeper创建和删除有序临时节点实现 https://www.jianshu.com/p/da6ef8031eb6（暂时没有更好的原理文章）

使用实例（RedisLockRegistry、ZookeeperLockRegistry 可独立使用，本文为方便才放在一起）：

1.首先引入依赖

<dependency>
 <groupId>org.springframework.integration</groupId>
 <artifactId>spring-integration-zookeeper</artifactId> </dependency> <dependency>
 <groupId>org.springframework.integration</groupId>
 <artifactId>spring-integration-redis</artifactId> </dependency></pre>

2.配置bean

@Configuration public class RedisLockConfiguration {   
 @Bean
  public RedisLockRegistry redisLockRegistry(
  RedisConnectionFactory redisConnectionFactory
  ) {
  // 注意这里的时间单位是毫秒
  return new RedisLockRegistry(redisConnectionFactory, "redis_lock_ledger", 1000 * 40L);
  } } 

@Configuration public class ZookeeperLockConfiguration {
  @Value("${spring.elasticjob.zookeeper.server-lists}")
  private String url;    
@Bean
  public ZookeeperLockRegistry zookeeperLockRegistry() { // 重试策略，重试时间1s，重试10次
  RetryPolicy policy = new ExponentialBackoffRetry(1000, 10); // 通过工厂创建 Curator  CuratorFramework newClient = CuratorFrameworkFactory.newClient(url, policy);
  newClient.start();
  // 注意这里的时间单位是毫秒
  return new ZookeeperLockRegistry(newClient);
  } }

3.使用锁

注入bean

使用ZookeeperLockRegistry： Lock lock = zookeeperLockRegistry.obtain(key);
使用RedisLockRegistry： Lock lock = redisLockRegistry.obtain(key); </pre>

Lock lock = null;
  try {
....
//       指定key
  lock = zookeeperLockRegistry.obtain(key);
 // lock = redisLockRegistry.obtain(key);
 //      尝试获取锁   getLock = lock.tryLock(1, TimeUnit.SECONDS);
  if (!getLock) { 
  log.info("获取分布式锁超时{}", key);
  return;
  }
// 获取分布式锁成功、开始执行业务代码
  。。。。业务代码。。。。    } catch (InterruptedException e) {
  e.printStackTrace();
  } finally {
 //      释放放锁
  if (getLock) {
  lock.unlock();
  }
 }