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(); } } }