Java library to check whether a String contains a number *without* exceptions

Question

I\'m looking for a method that returns a boolean if the String it is passed is a valid number (e.g. \"123.55e-9\", \"-333,556\"). I don\'t want to just do:

Answer 1

Yeah a regular expression should do the trick. I only know .Net regexp but all regex languages are fairly similar so this should get you started. I didn't test it so you might want to kick it around a bit with the Java regex class.

"-?(([0-9]{1,3}(,[0-9{3,3})*)|[0-9]*)(\.[0-9]+(e-?[0-9]*)?)?"

Some of the Regex control syntax:
? - Optional element
| - OR operator. Basically I allowed numbers with or without commas if they were formatted correctly.
[ ] - Set of allowed characters
{ , } - Minimum maximum of element
* - Any number of elements, 0 to infinity
+ - At least one element, 1 to infinity
\ - Escape character
. - Any character (Hence why it was escaped)