How to Parse ISO 8601 Date Format in Java: 2011-08-12T20:17:46.384Z

What date format is 2011-08-12T20:17:46.384Z?

The date string "2011-08-12T20:17:46.384Z" follows the ISO 8601 format, which is widely used for representing dates and times in a standardized manner. To parse this format in Java, particularly if you are using an older version like Java 1.4, you will need to utilize the SimpleDateFormat class with a specific format string that captures both the date and time components as well as the timezone information.

import java.text.SimpleDateFormat;
import java.util.Date;

public class DateParser {
    public static void main(String[] args) {
        String dateStr = "2011-08-12T20:17:46.384Z";
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        try {
            Date date = format.parse(dateStr);
            System.out.println(date);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Causes

• The string uses 'T' as a separator between the date and time components, which is standard in ISO 8601.
• The 'Z' at the end indicates that the time is in UTC (Coordinated Universal Time).
• The presence of milliseconds (.384) requires your format to accommodate this detail.

Solutions

• Use SimpleDateFormat with the pattern "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", where:
• - 'yyyy' represents the year.
• - 'MM' represents the month.
• - 'dd' represents the day of the month.
• - 'T' is a literal character separating date and time.
• - 'HH' represents the hour (0-23).
• - 'mm' represents minutes.
• - 'ss' represents seconds.
• - 'SSS' represents milliseconds.
• - 'Z' is a literal indicating UTC.

Mistake: Using DateFormat.getDateInstance() for ISO 8601 formatting.

Solution: Use SimpleDateFormat with the appropriate pattern instead.

Mistake: Not accounting for the 'Z' in the date string.

Solution: Include 'Z' in the format string as a literal.

Mistake: Forget to pattern for milliseconds.

Solution: Make sure to include 'SSS' in the format for milliseconds.