Java中的日期差异计算 [英] Date difference calculation in Java
本文介绍了Java中的日期差异计算的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我想计算两个日期之间的差异。
目前,我在做:
I want to calculate the difference between two dates. Currently, I am doing:
Calendar firstDate = Calendar.getInstance();
firstDate.set(Calendar.DATE, 15);
firstDate.set(Calendar.MONTH, 4);
firstDate.get(Calendar.YEAR);
int diff = (new Date().getTime - firstDate.getTime)/(1000 * 60 * 60 * 24)
这给我输出0.但是我希望当新的Date()为15时,我应该得到输出0.当前的新日期是14.它使我进一步的计算错误我很困惑如何解决这个。请建议。
This gives me output 0. But I want that I should get the output 0 when the new Date() is 15. Currently the new date is 14. It makes my further calculation wrong and I am confused how to resolve this. Please suggest.
推荐答案
找出两个日期之间的差异并不像
减去两个日期并将结果除以(24 * 60 * 60 *
1000)。
Finding the difference between two dates isn't as straightforward as subtracting the two dates and dividing the result by (24 * 60 * 60 * 1000). Infact, its erroneous!
/* Using Calendar - THE CORRECT (& Faster) WAY**/
//assert: startDate must be before endDate
public static long daysBetween(final Calendar startDate, final Calendar endDate) {
int MILLIS_IN_DAY = 1000 * 60 * 60 * 24;
long endInstant = endDate.getTimeInMillis();
int presumedDays = (int) ((endInstant - startDate.getTimeInMillis()) / MILLIS_IN_DAY);
Calendar cursor = (Calendar) startDate.clone();
cursor.add(Calendar.DAY_OF_YEAR, presumedDays);
long instant = cursor.getTimeInMillis();
if (instant == endInstant)
return presumedDays;
final int step = instant < endInstant ? 1 : -1;
do {
cursor.add(Calendar.DAY_OF_MONTH, step);
presumedDays += step;
} while (cursor.getTimeInMillis() != endInstant);
return presumedDays;
}
您可以阅读更多此处。
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