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  • Java分布式集群,使用synchronized和Redis保证Job的原子性

    1.使用synchronized保证并发时,同时只会有一个请求执行该代码段;

    2.在执行前先设置并获取Reids标记,先设置然后获取确保是否已经执行;SetOption.SET_IF_ABSENT 可以保证Reids如果存在Key的话就不再Set;

    public synchronized static boolean isWorking(final String keyLock, final String uuidValue,long seconds){
            
            if(null == keyLock || uuidValue == null) {
                return false;
            }
            RedisConnection redisConnection = null;
            try {
                JedisConnectionFactory jedisConnectionFactory = ac.getBean("jedisConnectionFactory", JedisConnectionFactory.class);
                StringRedisTemplate redisTemplate = new StringRedisTemplate(jedisConnectionFactory);
                String value = System.currentTimeMillis() + "::" + uuidValue;
                logger.info("{} 尝试获取锁: {}, value:{}", ip, keyLock, value);
                //必须设置和过期同时执行
                redisConnection = redisTemplate.getConnectionFactory().getConnection();
                redisConnection.set(keyLock.getBytes(),
                        value.getBytes(), Expiration.seconds(seconds), SetOption.SET_IF_ABSENT);
                
                if(value.equals(redisTemplate.opsForValue().get(keyLock))){
                    logger.info("{} 成功获取锁: {}, value:{}", ip, keyLock, value);
                    return true;
                }
                logger.info("{} 无法获取锁: {}, value:{}", ip, keyLock, value);
                return false;
            }catch(Exception e) {
                logger.error(e.getMessage(), e);
                return false;
            }finally {
                if(null != redisConnection) {
                    redisConnection.close();
                }
            }
            
        }
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  • 原文地址:https://www.cnblogs.com/raphael5200/p/9012984.html
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