Question

I have a Java date object:

Date currentDate = new Date();

This will give the current date and time. Example:

Thu Jan 12 10:17:47 GMT 2012

Instead, I want to get the date, changing it to one hour back so it should give me:

Thu Jan 12 09:17:47 GMT 2012

What would be the best way to do it?

Answer 1

java.util.Calendar

Calendar cal = Calendar.getInstance();
// remove next line if you're always using the current time.
cal.setTime(currentDate);
cal.add(Calendar.HOUR, -1);
Date oneHourBack = cal.getTime();

java.util.Date

new Date(System.currentTimeMillis() - 3600 * 1000);

org.joda.time.LocalDateTime

new LocalDateTime().minusHours(1)

Java 8: java.time.LocalDateTime

LocalDateTime.now().minusHours(1)

Java 8 java.time.Instant

// always in UTC if not timezone set
Instant.now().minus(1, ChronoUnit.HOURS));
// with timezone, Europe/Berlin for example
Instant.now()
       .atZone(ZoneId.of("Europe/Berlin"))
       .minusHours(1));