Java LocalDateTime Format toDoubleExcelFormat(LocalDateTime date, boolean date1904)

Description

to Double Excel Format

License

Open Source License

Declaration

public static String toDoubleExcelFormat(LocalDateTime date, boolean date1904) 

Method Source Code

//package com.java2s;
//License from project: Open Source License 

import java.time.LocalDateTime;

import java.time.temporal.ChronoUnit;

public class Main {
    public static String toDoubleExcelFormat(LocalDateTime date, boolean date1904) {
        if (date == null)
            return "";

        LocalDateTime from;/*from   www  .j a v  a  2  s.c  o  m*/

        // Excel has 2 date systems:
        // - https://support.microsoft.com/pt-br/help/214330/differences-between-the-1900-and-the-1904-date-system-in-excel
        if (date1904) {
            from = LocalDateTime.of(1904, 1, 1, 0, 0, 0);
        } else {
            from = LocalDateTime.of(1900, 1, 1, 0, 0, 0);
            // http://polymathprogrammer.com/2009/10/26/the-leap-year-1900-bug-in-excel/
            if (date.isBefore(LocalDateTime.of(1900, 3, 1, 0, 0, 0))) {
                from = from.minusDays(1);
            } else {
                from = from.minusDays(2);
            }
        }

        long millis = from.until(date, ChronoUnit.MILLIS);

        // excel hours are represented as a fraction of a day
        double dayMillis = 24.0 * 60.0 * 60.0 * 1000.0;

        return Double.toString(millis / dayMillis);
    }
}

Related

1. formatShortDate(LocalDateTime dateTime)
2. formattedWeek(LocalDateTime localDateTime)
3. formatTime(LocalDateTime dateTime)
4. formatTime(LocalDateTime time)
5. localDateTime2Str(LocalDateTime localDateTime, String dateTimeFormatter)
6. toLocalDateTime(String date, DateTimeFormatter formatter)
7. toString(LocalDateTime ldt, DateTimeFormatter formatter)