How to convert String to Date without knowing the format?

user_37298 0
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I have a problem. I am trying to convert some strings to date, and I don't know the format the date is arriving.

It might come as yyyy.mm.dd hh:mm:ss or MM.dd.yy hh:mm:ss and so on.

How can I convert these strings to Date? I tried this:

DateFormat formatter = new SimpleDateFormat("dd-MM-yyyy hh:mm:ss");
Date d = (Date)formatter.parse(someDate);

But when I printed out someDate it printed out like this: 2010-08-05 12:42:48.638 CEST which means yyyy.mm.dd hh:mm:ss, however when I ran the above code, the date object now became Sat Jan 31 00:42:48 CET 11 which is strange to say the least.

Any ideas how I can correctly format strings to date?

format date java
11 Answers

This answer is a copy of my answer to another question that is marked as duplicate of this one

I once had a task to write a code that would parse a String to date where date format was not known in advance. I.e. I had to parse any valid date format. I wrote a project and after that I wrote an article that described the idea behind my implementation. Here is the link to the article: Java 8 java.time package: parsing any string to date. General Idea is to write all the patterns that you wish to support into external properties file and read them from there and try to parse your String by those formats one by one until you succeed or run out of formats. Note that the order also would be important as some Strings may be valid for several formats (US/European differences). Advantage is that you can keep adding/removing formats to the file without changing your code. So such project could also be customized for different customers

user_58024170

I created a utility that tries to parse some common date formats. It tries to check which digit is greater than 12 or else if both are less than 12 it prefers user-defined boolean preferMonthFirst based on which it will choose between MM/dd/yyyy or dd/MM/yyyy

It also accepts prefer24HourTime boolean for parsing time.

I did not use the list and iterate over it and try to parse it and tried to catch exception because Exceptions are costlier. So based on separator and length I tried to find the date format.

You can find usages in the test cases.

https://github.com/rajat-g/DateParser

user_48210210
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