How to check if a String is numeric in Java

Question

How would you check if a String was a number before parsing it?

Answer 1

I modified CraigTP's solution to accept scientific notation and both dot and comma as decimal separators as well

^-?\d+([,\.]\d+)?([eE]-?\d+)?$

example

var re = new RegExp("^-?\d+([,\.]\d+)?([eE]-?\d+)?$");
re.test("-6546"); // true
re.test("-6546355e-4456"); // true
re.test("-6546.355e-4456"); // true, though debatable
re.test("-6546.35.5e-4456"); // false
re.test("-6546.35.5e-4456.6"); // false