validating a date using dateformat

Question

I am trying to validate a date which is actually a string, trying to print it in yyyy/MM/dd format. Here is the code.

String s="2012/12/0390990";
SimpleDateFormat ft = new SimpleDateFormat("yyyy/MM/dd");
System.out.println(ft.format(ft.parse(s)));

and the output is 3083/05/30. I want to have the validations too. No clue how to proceed.

BalusC · Accepted Answer · 2012-10-24T21:25:22.880

5

It's by default lenient. You need to set it non-lenient before parsing.

ft.setLenient(false);

This will result in a ParseException when an invalid day and/or month is been supplied as compared to the year. Note that this doesn't validate the year itself as basically any number of years is valid. Depending on the concrete functional requirement, you might want to do an additional check on the year, e.g. split string on / and then check if the length of the 1st part is 4.

edited Oct 24 '12 at 21:25

answered Oct 24 '12 at 20:47

BalusC

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But why does lenient parsing result in a date that seems to different from the input... – Miserable Variable Oct 24 '12 at 20:55
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@Miserable: 390990 days is about 1071 years. It's literally been interpreted and rolled into the month/year to fit the amount of days the month can hold. You end up about 1071 years further. – BalusC Oct 24 '12 at 20:56

score -2 · Answer 2 · edited May 23 '17 at 12:12

-2

You might better use a RegExp to validate input,
see for example this answer:
https://stackoverflow.com/a/2149692/1448704

Sebastian

edited May 23 '17 at 12:12

Community

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answered Oct 24 '12 at 20:48

seba.wagner

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DateFormat is more suitable than a regex for this task. – Keppil Oct 24 '12 at 20:50

validating a date using dateformat

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