Extracting dates using Java by matching date format from string

Question

Is anybody aware of a third-party package that directly finds portions of an input string that match a Java DateFormat? In other words, that converts a DateFormat to a regular expression?

E.g., it might convert;

DateFromat df = new SimpleDateFormat("MM/dd/yyyy")

to something like "(0[1-9]|1[0-2])\\/(0[1-9]|1[0-9]|2[0-9]|3[01])\\/([0-9]{4})" so that you would have seamless methods available like (fantasy code):

DateFormat df = new SimpleDateFormat("MM/dd/yyyy");

DateMatcher dm = df.dateMatcher(inputString);

while (dfm.findDate()) {
#dostuff
}; // or 

if (dfm.matchesDate()) #dosomething

http://stackoverflow.com/questions/3850784/recognise-an-arbitrary-date-string — user1519979, Nov 25 '14 at 16:08

score 2 · Accepted Answer · answered Dec 04 '14 at 22:41

2

SimpleDateFormat#toPattern gets the pattern String of your SimpleDateFormat instance! So instantiate a SimpleDateFormat with the constructor of your choice and use toPattern to extract the pattern String.

answered Dec 04 '14 at 22:41

Daniel

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Puneet Jaiswal · Answer 2 · 2015-02-07T01:08:09.443

1

yes this magic parser code is available in joda-time package. Check the implementation of DateTimeParser there.

Check classes InternalParserDateTimeParser, DateTimeParserBucket to understand how jodatime extracts date as given pattern from the input line.

edited Feb 07 '15 at 01:08

answered Jan 23 '15 at 18:14

Puneet Jaiswal

313
4
9

Extracting dates using Java by matching date format from string

2 Answers2