Find Format of Date in Java

Question

How can we get the format of a date in Java?? I have a column which is in the date format . I want to find its format for every rows. How can i do this ? Ex --

COL1| COL2          |COL3
-------------------------
1   | 12-2005-31    |zzz
2   | 24 March 2009 |aaa

How would you distinguish between a numerical month and a day of month <= 12? — Alistair A. Israel, Nov 11 '11 at 08:49
some date formats are ambiguous. 10-11-12 could be 2010 Nov 12 or 10 Nov 2012 or Oct 11, 2012. — Peter Lawrey, Nov 11 '11 at 08:52
why do you have different formats in the same column? it is not safe to interpret date formats through code. I would suggest that you fix the formats in the column/ source. — aishwarya, Nov 11 '11 at 09:07
ok convert the date to string using dateValue.toString() . Once we get it in string check dis discussion http://stackoverflow.com/questions/8008000/string-to-date-with-no-format-specified — justin3250, Nov 11 '11 at 09:22

score 1 · Answer 1 · edited May 23 '17 at 12:03

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As per this SO answer, Generic way to parse dates in Java, there is no way to this. There are some partial solutions, but nothing definitive.

edited May 23 '17 at 12:03

Community

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answered Nov 11 '11 at 08:52

Pieter

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score 1 · Answer 2 · answered Nov 11 '11 at 08:54

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Looks like you are storing date as strings in your database. I suggest you change the column type to Date or Timestamp in the database table and save yourself from parsing horrors.

answered Nov 11 '11 at 08:54

Manish

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score 1 · Answer 3 · answered Nov 11 '11 at 09:03

You cannot simply parse a string to form a Date because of the obvious ambiguity associated with the interpretation of the date string. For example, consider the date presented as "10/12/2009". One can interpret it as 10th of December and also as 12th of October. You can not map this string to a definitive date value unless you know the pattern it conforms to.

I agree with @Manish Sharma that changing the column type to Date would be a solution to your problem because Date values are stored as absolute seconds value starting from some fixed date in the past.

score 0 · Answer 4 · answered Nov 11 '11 at 09:05

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You will have to do your own heuristic or simply said "guess". Create a list of regexp Patterns and use the first that matches to construct a Date instance. Hope that your date's formats in database are not too variable.

answered Nov 11 '11 at 09:05

Rostislav Matl

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Find Format of Date in Java

4 Answers4