How to parse ISO date with microsecond precision in Kotlin

December 29, 2022

I got this from https://stackoverflow.com/a/18217193/6727914

val df1: DateFormat = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ")
val string1 = "2022-12-29T19:59:20.783357Z"
val result1: Date = df1.parse(string1)

But it does not work:

Exception in thread "main" java.text.ParseException: Unparseable date:
"2022-12-29T19:59:20.783357Z" at java.text.DateFormat.parse (:-1)
at FileKt.main (File.kt:13) at FileKt.main (File.kt:-1)

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I can’t use Instant.parse(date)

The date "2022-12-29T19:59:20.783357Z" is a valid Iso8601String where 783 is the milliseconds and 357 is the micro seconds

>Solution :

SimpleDateFormat can not handle fraction-of-second up to microseconds resolution, its limit is up to millisecond resolution. If you try to parse it as it is, you will get the wrong result as explained in this answer.

You have two choices:

Truncate fraction of second up to milliseconds resolution
Use ThreeTenABP which is an adaptation of the JSR-310 backport for Android.

Note: In any case, you need to use X instead of Z in the pattern.

Demo:

import java.text.ParseException;
import java.text.SimpleDateFormat;

public class Main {
    public static void main(String[] args) throws ParseException {
        var df1 = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSX");
        var string1 = "2022-12-29T19:59:20.783357Z";
        string1 = string1.replaceAll("(\\.\\d{3})\\d+", "$1");
        var result1 = df1.parse(string1);
        System.out.println(result1);
    }
}

Output in my time zone, Europe/London: