Redis实现分布式锁3-使用LUA脚本实现分布式锁,解决原子性问题

2020-04-02 18:10:47 浏览数 (2)

代码语言:javascript复制
private   static   final   Long SUCCESS = 1L;
private   static   String script1 =  "if redis.call('setNx',KEYS[1],ARGV[1])  then "    
         "   if redis.call('get',KEYS[1])==ARGV[1] then "    
         "      return redis.call('expire',KEYS[1],ARGV[2]) "    
         "   else "    
         "      return 0 "    
         "   end "    
         "end" ;
private   RedisScript<String> lockRedisScript1 =  new   DefaultRedisScript<>(script1, String. class );
private   static   String script2 =  "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end" ;
private   RedisScript<String> unLockRedisScript =  new   DefaultRedisScript<>(script2, String. class );
/**
  * 获取锁
  *
  * @param lockKey       redis的key
  * @param value         redis的value要求是随机串,防止释放其他请求的锁
  * @param expireTime    redis的key 的过期时间  单位(秒) 防止死锁,导致其他请求无法正常执行业务
  * @return
  */
@Override
public    boolean   lock(String lockKey, String value,  long   expireTime) {
     //对非string类型的序列化
     redisTemplate.setKeySerializer( new   StringRedisSerializer());
     redisTemplate.setValueSerializer( new   StringRedisSerializer());
     Object result = redisTemplate.execute(lockRedisScript1, Collections.singletonList(lockKey), value, String.valueOf(expireTime));
 
     return   SUCCESS.equals(result);
 
}
 
/**
  * 释放锁
  *
  * @param lockKey   redis的key
  * @param value     redis的value  只有value比对一致,才能确定是本请求 加的锁 才能正常释放
  * @return
  */
@Override
public    boolean   unlock(String lockKey, String value) {
     try   {
         Object result = redisTemplate.execute(unLockRedisScript, Collections.singletonList(lockKey), value);
         if   (SUCCESS.equals(result)) {
             return   true ;
         }
     }  catch   (Exception e) {
         e.printStackTrace();
     }
     return   false ;
}

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