订单号生成

实时生成，适合并发不高的场景，利用redis自增特性，单号构成为：
2位年份+2位月份+2位日+5位当天经过秒数+5位自增=16位

@Component
public class OrderNoUtil {

    @Autowired
    RedisTemplate redisTemplate;

    public String getNo() {
        String incrKey = "incr_no";
        LocalDateTime now = LocalDateTime.now();
        int hour = now.getHour();
        int minute = now.getMinute();
        int second = now.getSecond();
        int year = now.getYear() / 100;
        int monthValue = now.getMonthValue();
        int dayOfMonth = now.getDayOfMonth();
        int secondOfDay = hour * 3600 + minute * 60 + second;
        return String.format("%02d%02d%02d%05d%05d", year, monthValue, dayOfMonth, secondOfDay, getIncrInt(incrKey));
    }

    private Integer getIncrInt(String key) {
        RedisAtomicInteger redisCount = new RedisAtomicInteger(key, redisTemplate.getConnectionFactory());
        int i = redisCount.incrementAndGet();
        if (i == 1) {
            redisCount.expire(60, TimeUnit.SECONDS);
        }
        return i;
    }

}