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

Question

I have the following date: 2011-08-12T20:17:46.384Z. What format is this? I\'m trying to parse it with Java 1.4 via DateFormat.getDateInstance().parse(

Answer 1

@John-Skeet gave me the clue to fix my own issue around this. As a younger programmer this small issue is easy to miss and hard to diagnose. So Im sharing it in the hopes it will help someone.

My issue was that I wanted to parse the following string contraining a time stamp from a JSON I have no influence over and put it in more useful variables. But I kept getting errors.

So given the following (pay attention to the string parameter inside ofPattern();

String str = "20190927T182730.000Z"

LocalDateTime fin;
fin = LocalDateTime.parse( str, DateTimeFormatter.ofPattern("yyyyMMdd'T'HHmmss.SSSZ") );

Error:

Exception in thread "main" java.time.format.DateTimeParseException: Text 
'20190927T182730.000Z' could not be parsed at index 19

The problem? The Z at the end of the Pattern needs to be wrapped in 'Z' just like the 'T' is. Change "yyyyMMdd'T'HHmmss.SSSZ" to "yyyyMMdd'T'HHmmss.SSS'Z'" and it works.

Removing the Z from the pattern alltogether also led to errors.

Frankly, I'd expect a Java class to have anticipated this.

Answer 2

You can use the following example.

    String date = "2011-08-12T20:17:46.384Z";

    String inputPattern = "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'";

    String outputPattern = "yyyy-MM-dd HH:mm:ss";

    LocalDateTime inputDate = null;
    String outputDate = null;


    DateTimeFormatter inputFormatter = DateTimeFormatter.ofPattern(inputPattern, Locale.ENGLISH);
    DateTimeFormatter outputFormatter = DateTimeFormatter.ofPattern(outputPattern, Locale.ENGLISH);

    inputDate = LocalDateTime.parse(date, inputFormatter);
    outputDate = outputFormatter.format(inputDate);

    System.out.println("inputDate: " + inputDate);
    System.out.println("outputDate: " + outputDate);