How to round time to the nearest quarter hour in java?

Question

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

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

Answer 1

Using some code on I found on Stackoverflow, I have created the following code. It will output for every minute the quarter it will be rounded to.

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

DateTimeFormatter Datum_Format = DateTimeFormatter.ofPattern("HH:mm");

LocalDateTime time = LocalDateTime.now();
for(int i=0; i<=59; i++) {
  time = time.withMinute(i);
  int Minute = time.getMinute();
  int Quarter = 15 * (int) Math.round(Minute / 15);
  if (Quarter == 60) { 
    Time2 = time.plusHours(1);
    Time2 = Time2.withMinute(0); 
    LOG.info (Datum_Format.format(time) + "," + Datum_Format.format(Time2));
  }
  else {
    Time2 = time; 
    Time2 = Time2.withMinute(Quarter); 
    LOG.info (Datum_Format.format(time) + "," + Datum_Format.format(Time2));
  }
}

As I output the code to a console, you will have to replace the LOG.info with something like System.out.println.

Result:

2016-08-16 15:14:31 INFO 15:05,15:00
2016-08-16 15:14:31 INFO 15:06,15:00
2016-08-16 15:14:31 INFO 15:07,15:00
2016-08-16 15:14:31 INFO 15:08,15:15
2016-08-16 15:14:31 INFO 15:09,15:15
2016-08-16 15:14:31 INFO 15:10,15:15