springboot redis的db动态切换没有作用

springboot2.x以上版本默认采用lettuce，而SpringBoot1.5默认采用的是jedis

//springboot2.x以上版本
LettuceConnectionFactory connectionFactory = (LettuceConnectionFactory) redisTemplate.getConnectionFactory();
        if (connectionFactory != null) {
            connectionFactory.setDatabase(切换到指定的db上);
            /**
             * 在重置db之后:connectionFactory.setDatabase(i);
             * 需要将链接刷新:connectionFactory.afterPropertiesSet();
             */
            connectionFactory.afterPropertiesSet();
            this.redisTemplate.setConnectionFactory(connectionFactory);
            connectionFactory.resetConnection();
        }

//springboot1.x
JedisConnectionFactory jedisConnectionFactory = (JedisConnectionFactory) stringRedisTemplate.getConnectionFactory();
 jedisConnectionFactory.setDatabase(切换到指定的db上);

jedisConnectionFactory.afterPropertiesSet();

stringRedisTemplate.setConnectionFactory(jedisConnectionFactory);

无法切换的原因：

　　resetConnnection()方法只会释放Connection对象，RedisClient中的redisUrl对象的属性并未刷新，导致重新生成的Connection对象的DB值仍未改变，随意切换未生效，所以需要调用

connectionFactory.afterPropertiesSet();刷新RedisClient