Julian day of the year in Java

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I have seen the "solution" at http://www.rgagnon.com/javadetails/java-0506.html, but it doesn't work correctly. E.g. yesterday (June 8) should have been 159, but it said it was 245.

So, does someone have a solution in Java for getting the current date's three digit Julian day (not Julian date - I need the day this year)?

Thanks! Mark


If all you want is the day-of-year, why don'you just use GregorianCalendars DAY_OF_YEAR field?

import java.util.GregorianCalendar;
public class CalTest {
    public static void main(String[] argv) {
        GregorianCalendar gc = new GregorianCalendar();
        gc.set(GregorianCalendar.DAY_OF_MONTH, 8);
        gc.set(GregorianCalendar.MONTH, GregorianCalendar.JUNE);
        gc.set(GregorianCalendar.YEAR, 2010);
        System.out.println(gc.get(GregorianCalendar.DAY_OF_YEAR));
}

}

Alternatively, you could calculate the difference between today's Julian date and that of Jan 1st of this year. But be sure to add 1 to the result, since Jan 1st is not the zeroth day of the year:

int[] now = {2010, 6, 8};
int[] janFirst = {2010, 1, 1};
double dayOfYear = toJulian(now) - toJulian(janFirst) + 1
System.out.println(Double.valueOf(dayOfYear).intValue());

Get a julian date, The following day will begin the first day of the second Julian date period (or 7,980 year cycle). import java.util.Calendar; public class JulianDate { /** * Returns  You can have the Modified Julian Date (JD) or the Truncated Julian Date (TJD) . The main difference is the starting for counting the days. Before Y2K, many applications (especially mainframe systems) were storing dates in a format called "the Julian format".


DateFormat d = new SimpleDateFormat("D");
System.out.println(d.format(date));

JulianFields (Java Platform SE 8 ), The Julian Day is a standard way of expressing date and time commonly used in the scientific community. It is expressed as a decimal number of whole days  Modified Julian Day (MJD) is a well-known system that counts days continuously. It is defined relative to astronomical Julian Day as MJD = JD - 2400000.5 . Each Modified Julian Day runs from midnight to midnight. The field always refers to the local date-time, ignoring the offset or zone.


import java.util.Calendar;
// ...
final int julianDay = Calendar.getInstance().get(Calendar.DAY_OF_YEAR);

Note that this doesn't take into account the "starts at noon" deal claimed by that weird site you referenced. That could be fixed by just checking the time of course.

JulianFields (Java Platform SE 8 ), Julian Day is a well-known system that represents the count of whole days since day 0, which is defined to be January 1, 4713 BCE in the Julian calendar, and -4713-11-24 Gregorian. The field has "JulianDay" as 'name', and 'DAYS' as 'baseUnit'. The field always refers to the local date-time, ignoring the offset or zone. Alternatively, you could calculate the difference between today's Julian date and that of Jan 1st of this year. But be sure to add 1 to the result, since Jan 1st is not the zeroth day of the year: int[] now = {2010, 6, 8}; int[] janFirst = {2010, 1, 1}; double dayOfYear = toJulian(now) - toJulian(janFirst) + 1 System.out.println(Double.valueOf(dayOfYear).intValue());


JulianDate.java, This calendar system is the forerunner to the modern Gregorian and ISO calendars. * The Julian differs from the Gregorian only in terms of the leap year rule. The term "Julian date" is ambiguous. Do you want a date in the Julian calendar, the one which predated the Gregorian Calendar? Or do you want a Julian day number, which is the number of days elapsed since noon on 1 January 4713 B.C. (GMT).


if we get a double julian date such as chordiant decision manager

http://java.ittoolbox.com/groups/technical-functional/java-l/java-function-to-convert-julian-date-to-calendar-date-1947446

The following is working but second is not taken care of How can I convert between a Java Date and Julian day number?

public static String julianDate(String julianDateStr) {

    try{
        // Calcul date calendrier Gr?gorien ? partir du jour Julien ?ph?m?ride 
        // Tous les calculs sont issus du livre de Jean MEEUS "Calcul astronomique" 
        // Chapitre 3 de la soci?t? astronomique de France 3 rue Beethoven 75016 Paris 
        // Tel 01 42 24 13 74 
        // Valable pour les ann?es n?gatives et positives mais pas pour les jours Juliens n?gatifs
        double jd=Double.parseDouble(julianDateStr);
          double z, f, a, b, c, d, e, m, aux;
            Date date = new Date();
            jd += 0.5;
            z = Math.floor(jd);
            f = jd - z;

            if (z >= 2299161.0) {
              a = Math.floor((z - 1867216.25) / 36524.25);
              a = z + 1 + a - Math.floor(a / 4);
            } else {
              a = z;
            }

            b = a + 1524;
            c = Math.floor((b - 122.1) / 365.25);
            d = Math.floor(365.25 * c);
            e = Math.floor((b - d) / 30.6001);
            aux = b - d - Math.floor(30.6001 * e) + f;
            Calendar calendar = new GregorianCalendar();
            calendar.setTime(date);
            calendar.set(Calendar.DAY_OF_MONTH, (int) aux);

            double hhd= aux-calendar.get(Calendar.DAY_OF_MONTH);                
            aux = ((aux - calendar.get(Calendar.DAY_OF_MONTH)) * 24);




            calendar.set(Calendar.HOUR_OF_DAY, (int) aux);

            calendar.set(Calendar.MINUTE, (int) ((aux - calendar.get(Calendar.HOUR_OF_DAY)) * 60));



         // Calcul secondes 
            double mnd = (24 * hhd) - calendar.get(Calendar.HOUR_OF_DAY);
            double ssd = (60 * mnd) - calendar.get(Calendar.MINUTE); 
            int ss = (int)(60 * ssd);
            calendar.set(Calendar.SECOND,ss);



            if (e < 13.5) {
              m = e - 1;
            } else {
              m = e - 13;
            }
            // Se le resta uno al mes por el manejo de JAVA, donde los meses empiezan en 0.
            calendar.set(Calendar.MONTH, (int) m - 1);
            if (m > 2.5) {
              calendar.set(Calendar.YEAR, (int) (c - 4716));
            } else {
              calendar.set(Calendar.YEAR, (int) (c - 4715));
            }


        SimpleDateFormat sdf=new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");
        //System.out.println("Appnumber= "+appNumber+" TimeStamp="+timeStamp+" Julian Date="+julianDateStr+" Converted Date="+sdf.format(calendar.getTime()));
        return sdf.format(calendar.getTime());

}catch(Exception e){
    e.printStackTrace();
}
return null;

}  

jodd.time.JulianDate java code examples, The Julian day or Julian day number (JDN) is the (integer) number of days that have elapsed since Monday, January 1, 4713 BC in the proleptic Julian calendar 1. This question already has answers here : Julian day of the year in Java (9 answers) Closed 3 years ago. I want to get the number of day.. i.e. Jan 1 is day 1 jan 2 is day 2 Feb 1 is day 32 and december 31 is day 365 or 366 depending on leap year or not.


Joda-Time – Java date and time API, The Julian calendar defines a leap year as once every four years. This becomes inaccurate over time, to such an extent that by 1582, 10 days had  Represents the creation date of the file in Julian date format (0YYDDD): 0 – numeric zero YY – last two digits of the year DDD – day number within the year Can be up to 7 calendar days before the date of transmission Example: 010163 = June 11, 2010. What is really looking is some thing like this


Julian day, Without an astronomical or historical context, a "Julian date" given as "36" most likely means the 36th day of a given Gregorian year, namely February 5. Other  Find answers to Convert given date (mm/dd/yyyy) to julian date (ddd) in java from the expert community at Experts Exchange


Julian day of the year in Java, JulianFields (Java Platform SE 8 ), Julian Day is a well-known system that represents the count of whole days since day 0, which is defined to be January 1, 4713  “Julian day” terminology. The term “Julian day” is sometimes used loosely to mean the ordinal day of the year, or Ordinal date, meaning a number from 1 to 365 or 366 . January 1 is 1, January 2 is 2, December 31 is 365 (or 366 in leap years).