使用redis实现自增序列

来源：

https://www.cnblogs.com/shigj/p/11215262.html

public class TestService {
  
    @Resource
    RedisTemplate<String, Object> redisTemplate;
     
    public String getId() {
        SimpleDateFormat sdf=new SimpleDateFormat("yyyyMMdd");
        Date date=new Date();
        String formatDate=sdf.format(date);
        String key="key"+formatDate;
        Long incr = getIncr(key, getCurrent2TodayEndMillisTime());
        if(incr==0) {
            incr = getIncr(key, getCurrent2TodayEndMillisTime());//从001开始
        }
        DecimalFormat df=new DecimalFormat("000");//三位序列号
        return formatDate+df.format(incr);
    }
     
    public Long getIncr(String key, long liveTime) {
            RedisAtomicLong entityIdCounter = new RedisAtomicLong(key, redisTemplate.getConnectionFactory());
            Long increment = entityIdCounter.getAndIncrement();
  
            if ((null == increment || increment.longValue() == 0) && liveTime > 0) {//初始设置过期时间
                entityIdCounter.expire(liveTime, TimeUnit.MILLISECONDS);//单位毫秒
            }
            return increment;
        }
  
    //现在到今天结束的毫秒数
    public Long getCurrent2TodayEndMillisTime() {
        Calendar todayEnd = Calendar.getInstance();
        // Calendar.HOUR 12小时制
        // HOUR_OF_DAY 24小时制
        todayEnd.set(Calendar.HOUR_OF_DAY, 23); 
        todayEnd.set(Calendar.MINUTE, 59);
        todayEnd.set(Calendar.SECOND, 59);
        todayEnd.set(Calendar.MILLISECOND, 999);
        return todayEnd.getTimeInMillis()-new Date().getTime();
    }
     
}