[FIXED] Single date formatter to parse dates with different syntax

Issue

I am having a java program . In my java program the input will be date strings of different formats like the following

a) 2021-10-09T08:00:01.111Z ( with millisecond)
b) 2021-10-09T08:00:01Z ( without milliseconds)
c) 2021-10-09T08:00Z ( no seconds )
d) 2021-10-09T08Z ( no minutes ) 

Currently I am using a built in date formatter DateTimeFormatter.ISO_OFFSET_DATE_TIME . However when i run my sample snippet program it fails

the following is my sample program

import java.time.OffsetDateTime;
import java.time.format.DateTimeFormatter;

public class Tester2 {

    public static void main(String[] args) {
        
        OffsetDateTime t1 = OffsetDateTime.parse("2021-10-09T08:00:01.111Z");;
        System.out.println(t1.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));
        
        OffsetDateTime t2 = OffsetDateTime.parse("2021-10-09T08:00:01Z");;
        System.out.println(t2.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));
        
        OffsetDateTime t3 = OffsetDateTime.parse("2021-10-09T08:00Z");;
        System.out.println(t3.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));
   
        OffsetDateTime t4 = OffsetDateTime.parse("2021-10-09T08Z");;
        System.out.println(t4.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));
    }

}

However when I run my program it fails with the following output.

2021-10-09T08:00:01.111Z
2021-10-09T08:00:01Z
2021-10-09T08:00:00Z
Exception in thread "main" java.time.format.DateTimeParseException: Text '2021-10-09T08Z' could not be parsed at index 13
    at java.base/java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:2052)
    at java.base/java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1954)
    at java.base/java.time.OffsetDateTime.parse(OffsetDateTime.java:404)
    at java.base/java.time.OffsetDateTime.parse(OffsetDateTime.java:389)
    at test.Tester2.main(Tester2.java:20)

The following is the output I want

2021-10-09T08:00:01.111Z
2021-10-09T08:00:01Z
2021-10-09T08:00:00Z
2021-10-09T08:00:00Z

Is there any java built in data formatter that will help me to achieve the desired output. If there is no such dateformatter could you help me to write a new date formatter ? Another solutions are welcome.

Solution

DataTimeFormatter supports optional parsing patterns with [ and ] characters.

    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH[:mm[:ss[.SSS]]]X");

    OffsetDateTime t1 = OffsetDateTime.parse("2021-10-09T08:00:01.111Z", formatter);
    System.out.println(t1.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));

    OffsetDateTime t2 = OffsetDateTime.parse("2021-10-09T08:00:01Z", formatter);
    System.out.println(t2.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));

    OffsetDateTime t3 = OffsetDateTime.parse("2021-10-09T08:00Z", formatter);
    System.out.println(t3.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));

    OffsetDateTime t4 = OffsetDateTime.parse("2021-10-09T08Z", formatter);
    System.out.println(t4.format(DateTimeFormatter.ISO_OFFSET_DATE_TIME));

Output is what you asked for:

2021-10-09T08:00:01.111Z
2021-10-09T08:00:01Z
2021-10-09T08:00:00Z
2021-10-09T08:00:00Z

Answered By - BccHnw
Answer Checked By - Dawn Plyler (JavaFixing Volunteer)