I need a method that can tell me if a String has non alphanumeric characters.
For example if the String is "abcdef?" or "abcdefà", the method must return true.
Using Apache Commons Lang:
!StringUtils.isAlphanumeric(String)
Alternativly iterate over String's characters and check with:
!Character.isLetterOrDigit(char)
You've still one problem left:
Your example string "abcdefà" is alphanumeric, since à
is a letter. But I think you want it to be considered non-alphanumeric, right?!
So you may want to use regular expression instead:
String s = "abcdefà";
Pattern p = Pattern.compile("[^a-zA-Z0-9]");
boolean hasSpecialChar = p.matcher(s).find();