How to validate jtextfield which accepts only float/decimal value in java swing?

Question

I am trying to validate text field such that it accepts float or double values like .25, 0.2, 111.25
It should not accepts values like ...25, 0.2.2. etc

Answer 1

-?(\d*\.)?\d+([eE][+\-]?\d+)?|[nN]a[nN]|[iI]nf(inity)? is the regex I usually use for parsing doubles.

If you don't want infinities and NaNs,

-?(\d*\.)?\d+([eE][+\-]?\d+)?

If you also don't want exponential notation,

-?(\d*\.)?\d+

And don't forget to escape backslashes if you need to.