如何在java中将时间缩短到最接近的四分之一小时？ [英] How to round time to the nearest quarter hour in java?

问题描述

鉴于今天的时间，例如下午2:24，如何让它圆到下午2:30？

Given today's time e.g. 2:24PM, how do I get it to round to 2:30PM?

同样如果时间是下午2:17，我该怎么把它变成2轮： 15PM？

Similarly if the time was 2:17PM, how do I get it to round to 2:15PM?

推荐答案

舍入

您需要使用模数来截断四分之一小时：

Rounding

You will need to use modulo to truncate the quarter hour:

Date whateverDateYouWant = new Date();
Calendar calendar = Calendar.getInstance();
calendar.setTime(whateverDateYouWant);

int unroundedMinutes = calendar.get(Calendar.MINUTE);
int mod = unroundedMinutes % 15;
calendar.add(Calendar.MINUTE, mod < 8 ? -mod : (15-mod));

正如EJP所指出的，这也没关系（替换最后一行，只有在日历是 lenient ）：

As pointed out by EJP, this is also OK (replacement for the last line, only valid if the calendar is lenient):

calendar.set(Calendar.MINUTE, unroundedMinutes + mod);

---

改进

如果你想要准确，你还必须截断较小的字段：

---

Improvements

If you want to be exact, you will also have to truncate the smaller fields:

calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.MILLISECOND, 0);

您还可以使用 DateUtils.truncate（） =http://commons.apache.org/lang =noreferrer> Apache Commons / Lang 这样做：

You can also use DateUtils.truncate() from Apache Commons / Lang to do this:

calendar = DateUtils.truncate(calendar, Calendar.MINUTE);

这篇关于如何在java中将时间缩短到最接近的四分之一小时？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！