How Would You Programmatically Create a Pattern from a Date that is Stored in a String?

Question

I have a string that contains the representation of a date. It looks like:

Thu Nov 30 19:00:00 EST 2006

I'm trying to create a Date object using SimpleDateFormat and have 2 problems.

1.) I can't figure out the pattern to hard-code the solution into the SimpleDateFormat constructor

2.) I can't find a way I could parse the string using API to determine the pattern so I could reuse this for different patterns of date output

If anyone knows a solution using API or a custom solution I would greatly appreciate it.

Answer 1

The format to pass to SimpleDateFormat could be looked up at http://java.sun.com/javase/6/docs/api/java/text/SimpleDateFormat.html

new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy")

As for your second question, I don't know of any Java library to figure out a date format and parse it without knowing in advance what the format is.

Answer 2

The POJava date parser org.pojava.datetime.DateTime is an immutable, and robust parser that supports multiple languages, time zones, and formats.

Best of all, the parser is heuristic and does not require a pre-existing “format” to work. You just pass it a date/date-time text string and get out a java.util.Date!

Answer 3

I'm not sure there's any easy way to parse a date and work out its pattern, but I would have thought that the pattern for the one you posted would be:

EEE MMM dd HH:mm:ss zzz yyyy