redisson同步锁

旧城等待， 2022-12-22 09:24 185阅读 0赞

## 实现： ##

*  基于zookeeper实现分布式锁  [https://mp.csdn.net/editor/html/109091509][https_mp.csdn.net_editor_html_109091509]
 *  基于Redis缓存实现分布式锁

## 1.redis  ##

Boolean isLockFree = RedisUtils.isLockFree(LIVE_LOCK, LIVE_LOCK, LOCK_TIME);
        if(!isLockFree){
            log.info("当前推送被锁定无法执行！！！");
            return;
        }
    
       public static boolean isLockFree(String key, String value,int circleSecond)
        {
            //返回0表示该key的资源已经被占用，不能修改
            long rs = getJedis().setnx(key, value);
            if (0 == rs)
            {
                return false;
            }
            //锁最多的持续时间,避免死锁.一定要加这个功能，为了避免重启服务的时候在执行中，导致死锁，下次无法启动服务
            getJedis().expire(key, circleSecond);
            return true;
        }

## 上面会有一个问题：如果缓存时间5s但是当前代码执行要10s,在还没执行完，锁就释放了，别的线程再去获取加锁也是成功的，会导致业务逻辑混乱或者脏数据。 ##

## 使用redisson能避免这个问题。 ##

# #

## 2.redisson ##

2.0 新建redisson.yml 四个文件内容一致，替换各自环境集群即可 ![20201119162407954.png][]

clusterServersConfig:
      idleConnectionTimeout: 10000
      connectTimeout: 10000
      timeout: 3000
      retryAttempts: 3
      retryInterval: 1500
      password: null
      subscriptionsPerConnection: 5
      clientName: null
      #loadBalancer: !<org.redisson.connection.balancer.RoundRobinLoadBalancer> {}
      slaveSubscriptionConnectionMinimumIdleSize: 1
      slaveSubscriptionConnectionPoolSize: 50
      slaveConnectionMinimumIdleSize: 32
      slaveConnectionPoolSize: 64
      masterConnectionMinimumIdleSize: 32
      masterConnectionPoolSize: 64
      readMode: "SLAVE"
      nodeAddresses:
        - "redis://172.28.1.127:7000"
        - "redis://172.28.1.127:7001"
        - "redis://172.28.1.127:7002"
      scanInterval: 1000
    threads: 0
    nettyThreads: 0

2.1

package com.test.mybatisplus.util;
    
    import lombok.extern.slf4j.Slf4j;
    import org.redisson.Redisson;
    import org.redisson.api.RedissonClient;
    import org.redisson.config.Config;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.core.io.ClassPathResource;
    
    @Configuration
    @Slf4j
    public class RedissonUtils {
    
        @Value("${spring.profiles.active}")
        private String active;
    
        @Bean
         public RedissonClient redissonClient() {
    
    //方式一
    //                 Config config = new Config();
    //
    //                 config.useClusterServers()
    //                         .setScanInterval(2000)
    //                         .addNodeAddress("redis://172.28.1.127:7000", "redis://172.28.1.127:7001")
    //                         .addNodeAddress("redis://172.28.1.127:7002");
    //
    //                RedissonClient redisson = Redisson.create(config);
    //方式二
            log.error("active::::::"+active);
            RedissonClient redisson =null;
                try {
                   // Config config1=Config.fromYAML(new ClassPathResource("redisson.yml").getInputStream());
                    Config config1=Config.fromYAML(new ClassPathResource("redisson-"+active+".yml").getInputStream());
                     redisson = Redisson.create(config1);
                }catch (Exception e){
                 log.error(e.getMessage());
                }
                  return redisson;
             }
    
    
    }

2.2

RLock lock=redissonUtils.redissonClient().getLock(ES_LOCK);
          try{
              if(lock.isLocked()){
                  log.info("islock");
              }else{
                  lock.lock();
                  //do something
                  String date= DateUtils.dateToStr(DateUtils.addDay(new Date(),-1), DateUtils.YYYY_MM_DD);
                  updateEsData(date);
              }
          }catch (Exception e){
             log.error(e.getMessage());
          }finally {
             //是否有锁且是否是当前线程持有
              if(lock.isLocked()&&lock.isHeldByCurrentThread()){
                  log.info("isHeldByCurrentThread");
                  lock.unlock();
              }
    
         }

[https_mp.csdn.net_editor_html_109091509]: https://mp.csdn.net/editor/html/109091509
[20201119162407954.png]: /images/20221120/3057c58364a941f29829276163260b17.png