In this article we will cover how to initialize a date time object with time set as the start of the day or midnight or at 00:00:00 AM in Java. We will do so using the legacy
Calendar class and we will also cover how this can be achieved using the Java 8
java.time classes like
When we say set time to start of day or midnight, we mean, if the date today is 3rd September 2019, and the time is any time of the say, when I run my code, I should get the date and time as 3rd Sptember 2019 00:00:00 AM i.e. the time of the start of the current day.
This can be achieved using the
Calendar class, but at times when we set the timezone to our specific timezone after creating a Calendar class instance, the results tend to vary. But if your usecase doesn't worry about the timezone factor you can use this approach. Here is the code for it,
java.time Package classes
With Java 8, the new
java.time package was introduced which came with many better options than
java.util.Calendar class. The
java.time package is close to joda-time library which provides many advanced functions for date and time processing.
Here is the code utilising the
You can use the following code too, to get the same output. In the code below we have used java.time.LocalDateTime class which doesn't take into consideration the timezone, so if you don't care about the timezone and want minimum code for some sample application, use it.
LocalDateTime now = LocalDateTime.now();
System.out.println(now.with(LocalTime.MIN)); // 2019-09-03T00:00
System.out.println(now.with(LocalTime.MIDNIGHT)); // 2019-09-03T00:00
If your project uses the joda-time jar file, you can use the following code for accomplishing this, although we recommend using the second technique where we use the java.time package classes.
DateTime now = new DateTime();
DateTime firstMomentOfToday = now.withTimeAtStartOfDay();
System.out.println( "now: " + now );
System.out.println( "firstMomentOfToday: " + firstMomentOfToday );
Hope this article helped you with this. And one of the above specified ways proved useful. If it did, then do share it around or bookmark it for later.
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