Regular expression for a valid filename without extension

Question

I need a regular expression pattern to check a string for alphanumeric(a-zA-z0-9) and also can contain underscore, hypen and dot this will be a file name so i dont want othe

Answer 1

Check out "Character Classes" in the docs. Basically, [a-zA-Z0-9_\-\.]+ should do it. If you put that in a string, be sure to escape the backslashes.

Answer 2

Re:

I need a regular expression pattern to check a string for alphanumeric(a-zA-z0-9) and also can contain underscore, hypen and dot

The pattern will be "[_a-zA-Z0-9\\-\\.]+"

Note the double-backslashes, since this is first interpreted as a Java string and the backslashes need to stay intact for the regex.