每天一篇開發日記,輕鬆快樂每一天！今天介紹的是利用java,Calendar類計算出兩個日期之間的天數和週數的演算法!

計算出日期之間的天數:

public Object countTwoDate(Object startDate, Object endDate) 
	{
		if(StringUtils.isNotEmpty(startDate) && StringUtils.isNotEmpty(endDate))
		{
			Date start=(Date)startDate;
			Date end = (Date)endDate;
			Calendar cal=Calendar.getInstance();
			cal.setTime(start);
			long time1=cal.getTimeInMillis();
			cal.setTime(end);
			long time2=cal.getTimeInMillis();
			long between_days=(time2-time1)/(1000*3600*24);
			return Integer.parseInt(String.valueOf(between_days));
		}
		return null;
	}
 

public Object countTwoDayWeek(Object startDate, Object endDate)
	{
		if(StringUtils.isNotEmpty(startDate) && StringUtils.isNotEmpty(endDate))
		{
			Date start=(Date)startDate;
			Date end = (Date)endDate;
			Calendar cal=Calendar.getInstance();
			cal.setTime(start);
			long time1=cal.getTimeInMillis();
			cal.setTime(end);
			long time2=cal.getTimeInMillis();
			long between_days=(time2-time1)/(1000*3600*24);
			Double days=Double.parseDouble(String.valueOf(between_days));
			if((days/7)>0 && (days/7)<=1){
				//不滿一週的按一週算
				return 1;
			}else if(days/7>1){
				int day=days.intValue();
				if(day%7>0){
					return day/7+1;
				}else{
					return day/7;
				}
			}else if((days/7)==0){
				return 0;
			}else{
				//負數返還null
				return null;
			}
		}
		return null;
	}