JDK8 - Java时间模块方式:

LocalDateTime todayMidnight = LocalDate.now（）.atStartOfDay（）;

也工作:

LocalDateTime todayMidnight = LocalDateTime.now（）.with（LocalTime.MIDNIGHT）;

Apache Commons Lang

DateUtils.isSameDay(date1, date2)

http://commons.apache.org/proper/commons lang/javadocs/api - 2.6 - / - org/apache/commons/lang/time/dateutils.html # isSameDay (java.util.Date java.util.Date)

和之前的答案差不多，但是没有人提到AM_PM参数:

    Calendar cal = Calendar.getInstance();
    cal.set(Calendar.HOUR, 0);
    cal.set(Calendar.MINUTE, 0);
    cal.set(Calendar.SECOND, 0);
    cal.set(Calendar.MILLISECOND, 0);
    cal.set(Calendar.AM_PM, Calendar.AM);

从JodaTime 2.3开始，toDateMidnight()已弃用。

从2.2升级到2.3

    Deprecations since 2.2
    ----------------------
    - DateMidnight [#41]
     This class is flawed in concept
     The time of midnight occasionally does not occur in some time-zones
     This is a result of a daylight savings time from 00:00 to 01:00
     DateMidnight is essentially a DateTime with a time locked to midnight
     Such a concept is more generally a poor one to use, given LocalDate
     Replace DateMidnight with LocalDate
     Or replace it with DateTime, perhaps using the withTimeAtStartOfDay() method

下面是一个没有toDateMidnight()方法的示例代码。

Code

DateTime todayAtMidnight = new DateTime().withTimeAtStartOfDay();
System.out.println(todayAtMidnight.toString("yyyy-MM-dd HH:mm:ss"));

输出(根据您所在的时区可能有所不同)

2013-09-28 00:00:00

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);

JDK 8 - java.time.LocalTime和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);

乔达时间

如果你使用的是小于8的JDK，我推荐Joda Time，因为这个API真的很棒:

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

因为2.3版本的Joda Time DateMidnight已弃用，所以使用这个:

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

如果不希望使用JVM当前的默认时区，则传递一个时区。

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

JodaTime最简单的方法

日期日期=日期日期。