How to round time to nearest 15 minute in java

问题

My program needs to calculate the overtime periods of workers for salary calculation purposes. To this end, what I am doing now is getting the worker's clock-in time and out time, then I calculate with the company's time scales and get how many hours overtime each worker has done. I need to round these times to the nearest 15 minutes, so I need a class to pass in the hours and return the rounded hours.

For example:

if the overtime hours is 2.17 hrs it must be rounded to 2.15.
if the overtime hours is 2.24 hrs it must be rounded to 2.30.
if the overtime hours is 2.40 hrs it must be 2.45.

if the overtime hours is 2.56 hrs it must be 3 hours.

public String RoundToNearest15Min(long Time) {

long milsec = Time;
System.out.println("milsecond :" + milsec);
long sec = Time / 1000;
ValidateValues.roundupDouble(sec);
System.out.println("second :" + sec);
double min = sec / 60;
ValidateValues.roundupDouble(min);
System.out.println("miniutes :" + min);
double hrs = min / 60;
System.out.println("hours :" + hrs);
double roundeVal = ValidateValues.roundupDouble(hrs);
String hrsvalue = String.valueOf(roundeVal);
System.out.println(hrsvalue);

String splitVal[] = hrsvalue.split("\\.");
System.out.println(splitVal[0]);
System.out.println(splitVal[1]);
int splitedValue2 = Integer.parseInt(splitVal[1]);
int splitedValue1 = Integer.parseInt(splitVal[0]);

if (splitedValue2 <= 15) {
    int rounded = splitedValue2 > 7 ? (15) : (0);
    return splitedValue1 + "." + rounded;
}
if (splitedValue2 > 15 && splitedValue2 <= 30) {
    int rounded = splitedValue2 > 22 ? (30) : (15);
    return splitedValue1 + "." + rounded;
}
if (splitedValue2 > 30 && splitedValue2 <= 45) {
    int rounded = splitedValue2 > 37 ? (45) : (30);
    return splitedValue1 + "." + rounded;
}
if (splitedValue2 > 45 && splitedValue2 <= 59) {
    int rounded = splitedValue2 > 51 ? (00) : (45);
    if (rounded == 00) {
        splitedValue1++;
        return splitedValue1 + "." + rounded;
    } else {
        return splitedValue1 + "." + rounded;
    }
}
return "";

}

回答1:

If you just can get minutes extracted from the time and pass it to this function:

public static int getNear15Minute(int minutes){
        int mod = minutes%15; 
        int res = 0 ;
        if((mod) >=8){
            res = minutes+(15 - mod);
        }else{
            res = minutes-mod;
        }
        return res; //return rounded minutes
    }

here I assumed number greater than or equal to 8 is near to 15.

回答2:

Example that uses current Date

import java.util.Calendar;
import java.util.Date;

public class Main {
    public static void main(String[] args) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(new Date());
        int round = calendar.get(Calendar.MINUTE) % 15;
        calendar.add(Calendar.MINUTE, round < 8 ? -round : (15-round));
        calendar.set( Calendar.SECOND, 0 );
        System.out.println(calendar.getTime());
    }
}

Test

Tue Jan 03 09:15:00 CET 2017

Online demo

回答3:

Well, rounding is easy to do with a modulo operation.

Here you want to round to a 15minutes.

Using the epoch time in milliseconds, you just need to remove the remainder of the modulo operation like this :

long l = System.currentTimeMillis();
l -= l % (15*60*1000);


System.out.println(new Date(System.currentTimeMillis()));
System.out.println(new Date(l));

Tue Jan 03 09:35:56 CET 2017

Tue Jan 03 09:30:00 CET 2017

15*60*1000 is simply the number of milliseconds in 15minutes

You just need to check the value of the remainder to add 15minute if need. So just store the remainder :

long r = l % (15*60*1000);

Then substract it to the current time

l -= r;

And check the number of minute (depends on the precision you really wants.

if( r / 60_000 >= 8)
     l += 15*60*1000;

This will round up if the quarter is past from 8minutes (if this really means anything in english ;) )

Full code :

long l = System.currentTimeMillis();
long r = l % (15*60*1000);
l -= r;
if( r / 60_000 >= 8)
     l += 15*60*1000;

来源：https://stackoverflow.com/questions/41438768/how-to-round-time-to-nearest-15-minute-in-java

标签

java

time

rounding