如何在今天午夜和明天午夜创建一个Java Date对象？ [英] how to create a Java Date object of midnight today and midnight tomorrow?

问题描述

在我的代码中，我需要找到我今天发生的一切事情。所以我需要从今天上午00:00（今天凌晨凌晨）到晚上12点（今晚午夜）的日期进行比较。

In my code I need to find all my things that happened today. So I need to compare against dates from today at 00:00am (midnight early this morning) to 12:00pm (midnight tonight).

我知道...

I know ...

Date today = new Date(); 

...现在得到我和...

... gets me right now. And ...

Date beginning = new Date(0);

...在1970年1月1日获得零时间。但是什么是简单的方法来获得零时间今天和零时间明天？

... gets me zero time on Jan 1, 1970. But what's an easy way to get zero time today and zero time tomorrow?

任何帮助是非常感谢！

更新;我这样做，但肯定有一个更简单的方法？

UPDATE; I did this, but surely there's an easier way??

Calendar calStart = new GregorianCalendar();
calStart.setTime(new Date());
calStart.set(Calendar.HOUR_OF_DAY, 0);
calStart.set(Calendar.MINUTE, 0);
calStart.set(Calendar.SECOND, 0);
calStart.set(Calendar.MILLISECOND, 0);
Date midnightYesterday = calStart.getTime();

Calendar calEnd = new GregorianCalendar();
calEnd.setTime(new Date());
calEnd.set(Calendar.DAY_OF_YEAR, calEnd.get(Calendar.DAY_OF_YEAR)+1);
calEnd.set(Calendar.HOUR_OF_DAY, 0);
calEnd.set(Calendar.MINUTE, 0);
calEnd.set(Calendar.SECOND, 0);
calEnd.set(Calendar.MILLISECOND, 0);
Date midnightTonight = calEnd.getTime();

推荐答案

java.util.Calendar

java.util.Calendar

// today    
Calendar date = new GregorianCalendar();
// reset hour, minutes, seconds and millis
date.set(Calendar.HOUR_OF_DAY, 0);
date.set(Calendar.MINUTE, 0);
date.set(Calendar.SECOND, 0);
date.set(Calendar.MILLISECOND, 0);

// next day
date.add(Calendar.DAY_OF_MONTH, 1);

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JDK 8 - java.time.LocalTime和java .time.LocalDate

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JDK 8 - java.time.LocalTime and java.time.LocalDate

LocalTime midnight = LocalTime.MIDNIGHT;
LocalDate today = LocalDate.now(ZoneId.of("Europe/Berlin"));
LocalDateTime todayMidnight = LocalDateTime.of(today, midnight);
LocalDateTime tomorrowMidnight = todayMidnight.plusDays(1);

---

Joda-Time

如果您使用JDK< 8，我推荐 Joda时间，因为API真的很棒：

---

Joda-Time

If you're using a JDK < 8, I recommend Joda Time, because the API is really nice:

DateTime date = new DateTime().toDateMidnight().toDateTime();
DateTime tomorrow = date.plusDays(1);

2.3的Joda时间 DateMidnight is deprecated ，所以使用这个：

Since version 2.3 of Joda Time DateMidnight is deprecated, so use this:

DateTime today = new DateTime().withTimeAtStartOfDay();
DateTime tomorrow = today.plusDays(1).withTimeAtStartOfDay();

如果您不想要JVM的当前默认时区，请传递时区。

Pass a time zone if you don't want the JVM’s current default time zone.

DateTimeZone timeZone = DateTimeZone.forID("America/Montreal");
DateTime today = new DateTime(timeZone).withTimeAtStartOfDay(); // Pass time zone to constructor.

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