SpringBoot下的redis：报错

String key = "TMS.INCR.TEST";
long count = redisTemplate.opsForValue().increment(key,1);
redisTemplate.expireAt(key, DateUtils.parseSimpleDate("2018-09-20 13:39:00"));
System.out.println(count);

RedisAtomicLong counter = new RedisAtomicLong(key,redisTemplate.getConnectionFactory());
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.MINUTE,21);
counter.expireAt(calendar.getTime());
long count = counter.incrementAndGet();
System.out.println(count);

以上两种方式，expireAt方法都无效，不知为何，请大神赐教