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javaandroidexceldatedate-conversion

Convert "using excel method" numeric value in date - java

I have an integer that when I put on Google Sheets, it represents the date 14/10/1911 (integer value is 4305).

I need to do this same conversion in my code using Java. So I'll have an array of integer that goes down by a factor of 1 (like 4305, 4304, 4303...) and I need to convert these integers into date (14/10/1911, 13/10/1911, 12/10/1911...) using the same method that excel/sheets uses.

Any ideas?

Thanks

Solution 
  •     LocalDate msBaseDate = LocalDate.of(1899, Month.DECEMBER, 30);
    int[] integers = { 4305, 4304, 4303 };
    for (int integerValue : integers) {
        LocalDate date = msBaseDate.plusDays(integerValue);
        System.out.println(date);
    }

    Output from this snippet is:

    1911-10-14
1911-10-13
1911-10-12

    Excel and other Microsoft products and possibly other software too use December 30, 1899, as a base date and represent dates as a count of days since that date. So just add the number to that date. I am using LocalDate from java.time, the modern Java date and time API.

    Question: Can I use java.time on Android?

    Yes, java.time works nicely on older and newer Android devices. It just requires at least Java 6.

    • In Java 8 and later and on newer Android devices (from API level 26) the modern API comes built-in.
    • In Java 6 and 7 get the ThreeTen Backport, the backport of the modern classes (ThreeTen for JSR 310; see the links at the bottom).
    • On (older) Android use the Android edition of ThreeTen Backport. It’s called ThreeTenABP. And make sure you import the date and time classes from org.threeten.bp with subpackages.

    Links