How to determine day of week by passing specific date?

Question

For Example I have the date: \"23/2/2010\" (23th Feb 2010). I want to pass it to a function which would return the day of week. How can I do this?

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Answer 1

Yes. Depending on your exact case:

• You can use java.util.Calendar:

  Calendar c = Calendar.getInstance();
  c.setTime(yourDate);
  int dayOfWeek = c.get(Calendar.DAY_OF_WEEK);
  

• if you need the output to be Tue rather than 3 (Days of week are indexed starting at 1 for Sunday, see Calendar.SUNDAY), instead of going through a calendar, just reformat the string: new SimpleDateFormat("EE").format(date) (EE meaning "day of week, short version")

• if you have your input as string, rather than Date, you should use SimpleDateFormat to parse it: new SimpleDateFormat("dd/M/yyyy").parse(dateString)

• you can use joda-time's DateTime and call dateTime.dayOfWeek() and/or DateTimeFormat.

• edit: since Java 8 you can now use java.time package instead of joda-time

Answer 2

For Java 8 or Later, Localdate is preferable

import java.time.LocalDate;

public static String findDay(int month, int day, int year) {

    LocalDate localDate = LocalDate.of(year, month, day);

    java.time.DayOfWeek dayOfWeek = localDate.getDayOfWeek();
    System.out.println(dayOfWeek);

    return dayOfWeek.toString();
}

Note : if input is String/User defined, then you should parse it into int.

Answer 3

There is a challenge on hackerrank Java Date and Time

personally, I prefer the LocalDate class.

1. Import java.time.LocalDate
2. Retrieve localDate by using "of" method which takes 3 arguments in "int" format.
3. finally, get the name of that day using "getDayOfWeek" method.

There is one video on this challenge.

Java Date and Time Hackerrank solution

I hope it will help :)

Answer 4

...
import java.time.LocalDate;
...
//String month = in.next();
int mm = in.nextInt();
//String day = in.next();
int dd = in.nextInt();
//String year = in.next();
int yy = in.nextInt();
in.close();
LocalDate dt = LocalDate.of(yy, mm, dd);
System.out.print(dt.getDayOfWeek());

Answer 5

//to get day of any date

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

public class Show {

    public static String getDay(String day,String month, String year){


            String input_date = month+"/"+day+"/"+year;

            Date now = new Date(input_date);
            Calendar calendar = Calendar.getInstance();
            calendar.setTime(now);
            int final_day = (calendar.get(Calendar.DAY_OF_WEEK));

            String finalDay[]={"SUNDAY","MONDAY","TUESDAY","WEDNESDAY","THURSDAY","FRIDAY","SATURDAY"};

            System.out.println(finalDay[final_day-1]);

    }

    public static void main(String[] args) { 
            Scanner in = new Scanner(System.in); 
            String month = in.next(); 
        String day = in.next();
            String year = in.next();

            getDay(day, month, year);
    }

}

Answer 6

Simply use SimpleDateFormat.

SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy", java.util.Locale.ENGLISH);
Date myDate = sdf.parse("28/12/2013");
sdf.applyPattern("EEE, d MMM yyyy");
String sMyDate = sdf.format(myDate);

The result is: Sat, 28 Dec 2013

The default constructor is taking "the default" Locale, so be careful using it when you need a specific pattern.

public SimpleDateFormat(String pattern) {
    this(pattern, Locale.getDefault(Locale.Category.FORMAT));
}