Question

I’ve to create a java regex that disable creation of databases.
(I’m following these restrictions: http://dev.mysql.com/doc/refman/5.0/en/identifiers.html)

Can anyone help me to build a regex with this restriction [0-9,a-z,A-Z$_] ?

This is my snippet:

    Pattern pattern = Pattern.compile("[0-9a-zA-Z$_]");
    Matcher matcher = pattern.matcher("userdatabase");
    System.out.println(matcher.matches());

Answer 1

You didn’t specify a quantifier. Your expression will only match one character.

Try changing it to:

Pattern pattern = Pattern.compile("[0-9a-zA-Z$_]+");

The + indicates that it should be that expressions 1 or more times.