Calculate Business Days between two dates using java

[pallavi chaudhari]

Hi experts,

I want to find the business days between two dates. I found following solution on google.

public static int getWorkingDaysBetweenTwoDates(Date startDate, Date endDate) {
    Calendar startCal;
    Calendar endCal;
    startCal = Calendar.getInstance();
    startCal.setTime(startDate);
    endCal = Calendar.getInstance();
    endCal.setTime(endDate);
    int workDays = 0;

    //Return 0 if start and end are the same
    if (startCal.getTimeInMillis() == endCal.getTimeInMillis()) {
        return 0;
    }

    if (startCal.getTimeInMillis() > endCal.getTimeInMillis()) {
        startCal.setTime(endDate);
        endCal.setTime(startDate);
    }

    do {
        startCal.add(Calendar.DAY_OF_MONTH, 1);
        if (startCal.get(Calendar.DAY_OF_WEEK) != Calendar.SATURDAY 
       && startCal.get(Calendar.DAY_OF_WEEK) != Calendar.SUNDAY) {
            ++workDays;
        }
    } while (startCal.getTimeInMillis() < endCal.getTimeInMillis());

    return workDays;
}

Is it good way to calculate business days?

Suggest a solution

Thanks

[Paul Clapham]

If it works for your test cases, then yes, it's a good way. But if it doesn't, then no, it isn't a good way.

What I'm saying: Set up some test cases and run the code to see if it produces the answer you want.

[Rob Spoor]

I don't like the loop's guard. It's too precise. What if you want to calculate the difference in days between 2011-08-08 09:00 and 2011-08-08 18:00? Your code would result in one day, whereas it should be 0 days.

The following should be a better guard:

while (startCal.get(Calendar.YEAR) < endCal.get(Calendar.YEAR) ||
       (startCal.get(Calendar.YEAR) == endCal.get(Calendar.YEAR) && startCal.get(Calendar.DAY_OF_YEAR) < endCal.get(Calendar.DAY_OF_YEAR)))

[fred rosenberger]

It is impossible to say if this is good or bad until you define what is a business day and what isn't. I work in healthcare, so EVERY day is a business day. Do you need to account for national holidays?

[Rob Spoor]

I wrote an entire library at work (which means I can't share the code...) that can calculate the difference in both days and minutes between any two timestamps, including opening and closing times and holidays - all configurable of course. It wasn't easy though.