How can I find Saturdays and Sundays in A given month?

Question

I want find all Saturdays and Sundays in A given month. How can I do so?

Answer 1

Try this:

import java.util.Calendar;
import java.util.GregorianCalendar;

public class Sundays {
    public static void main(String[] args) {
        int year = 2012;

        // put the month you want
        int month = Calendar.JANUARY;

        Calendar cal = new GregorianCalendar(year, month, 1);
        do {
            int day = cal.get(Calendar.DAY_OF_WEEK);
            if (day == Calendar.SATURDAY || day == Calendar.SUNDAY) {
                System.out.println(cal.get(Calendar.DAY_OF_MONTH));
            }
            cal.add(Calendar.DAY_OF_YEAR, 1);
        }  while (cal.get(Calendar.MONTH) == month);
    }
}

Answer 2

The simplest way is to just iterate over all the days in the month, and check the day of week for each of them. For example:

// This takes a 1-based month, e.g. January=1. If you want to use a 0-based
// month, remove the "- 1" later on.
public int countWeekendDays(int year, int month) {
    Calendar calendar = Calendar.getInstance();
    // Note that month is 0-based in calendar, bizarrely.
    calendar.set(year, month - 1, 1);
    int daysInMonth = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);

    int count = 0;
    for (int day = 1; day <= daysInMonth; day++) {
        calendar.set(year, month - 1, day);
        int dayOfWeek = calendar.get(Calendar.DAY_OF_WEEK);
        if (dayOfWeek == Calendar.SUNDAY || dayOfweek == Calendar.SATURDAY) {
            count++;
            // Or do whatever you need to with the result.
        }
    }
    return count;
}

I'm absolutely sure there are far more efficient ways of doing this - but that's what I'd start with, and optimize when I'd found it's too slow.

Note that if you're able to use Joda Time that would make your life a lot easier...

Answer 3

Base on the previous answer, I have a small modification When u find the first Saturday and Sunday, you can simply add 7 days to it until the month is changed.

Answer 4

Please go through this method, I faced a lot finally I created my own.

public static int getDayDiff(String dateFrom, String dateTo){ // DD/MM/YYYY
    Timestamp tDtF = getTimestampDDmmYYYY(dateFrom);//returning timestamp from / DD/MM/YYYY
    Timestamp tDtT = getTimestampDDmmYYYY(dateTo);
    Calendar dtF = new GregorianCalendar();
    Calendar dtT = new GregorianCalendar();
    dtF.setTimeInMillis(tDtF.getTime());
    dtT.setTimeInMillis(tDtT.getTime());
    int count = 0;
    while(dtF.before(dtT)){
        count++;
        dtF.add(Calendar.DAY_OF_YEAR, 1);
    }
    return count;
}

public static int countDateSatOrSun(String dateFrom, String dateTo){//DD/MM/YYYY
    Timestamp tDtF = getTimestampDDmmYYYY(dateFrom);//returning timestamp from / DD/MM/YYYY
    Timestamp tDtT = getTimestampDDmmYYYY(dateTo);
    Calendar dtF = new GregorianCalendar();
    Calendar dtT = new GregorianCalendar();
    dtF.setTimeInMillis(tDtF.getTime());
    dtT.setTimeInMillis(tDtT.getTime());
    int count = 0;
    while(dtF.before(dtT)){
        if((dtF.get(Calendar.DAY_OF_WEEK) == Calendar.SATURDAY| dtF.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY))
                count++;
        dtF.add(Calendar.DAY_OF_YEAR, 1);
    }
    return count;
}

It will give you exact result.