How to parse dates in multiple formats using SimpleDateFormat
datetime, java, parsing, simpledateformat
Solution
You'll need to use a different `SimpleDateFormat` object for each different pattern. That said, you don't need that many different ones, thanks to this:
Number: For formatting, the number of pattern letters is the minimum number of digits, and shorter numbers are zero-padded to this amount. For parsing, the number of pattern letters is ignored unless it's needed to separate two adjacent fields.
So, you'll need these formats:
- `"M/y"` (that covers `9/09`, `9/2009`, and `09/2009`)
- `"M/d/y"` (that covers `9/1/2009`)
- `"M-d-y"` (that covers `9-1-2009`)
So, my advice would be to write a method that works something like this (untested):
// ...
List<String> formatStrings = Arrays.asList("M/y", "M/d/y", "M-d-y");
// ...
Date tryParse(String dateString)
{
for (String formatString : formatStrings)
{
try
{
return new SimpleDateFormat(formatString).parse(dateString);
}
catch (ParseException e) {}
}
return null;
}
Problem
I am trying to parse some dates that are coming out of a document. It would appear users have entered these dates in a similar but not exact format. here are the formats: ``` 9/09 9/2009 09/2009 9/1/2009 9-1-2009 ``` What is the best way to go about trying to parse all of these? These seem to be the most common, but I guess what is hanging me up is that if i have a pattern of "M/yyyy" wont that always catch before "MM/yyyy" Do I have to set up my try/catch blocks nested in a least restrictive to most restrictive way? it seems like it sure is going to take a lot of code duplication to get this right.