CODEWITHSUNDEEP
javaregexstring
IAmYourFaja
IAmYourFaja

Reputation: 56934

Java String validation via blacklist

I want to write a simple validator to throw an exception if a String contains "illegal characters", specifically:

~, @, +, % and |

I'm searching for the cleanest way of doing this, and was hoping that there was a way to define a "blacklist" regex that might look something like:

String blacklist = "~@+%|";
String toValidate = getInputFromUser();

if(toValidate.matches(blacklist))
    throw new RuntimeException("Illegal characters found!");

However I know that the regex is incorrect. Am I heading in the right direction or am I way off base (i.e. is there a much simpler solution)? Thanks in advance!

Upvotes: 0

Views: 2306

Answers (2)

Anirudha
Anirudha

Reputation: 32807

The regex should be ^.*[~@+%|].*$

Alternatively you can use [~@+%|] with find method instead of matches

Upvotes: 5

Mirko Adari
Mirko Adari

Reputation: 5103

If you are looking a clear and concise way to do it I wouldn't use regexp, as it's API in Java tends to get messy. Apache commons-lang has StringUtils.containsAny("text","blacklisted");. It's usually a good library to include anyways as it complements Java with much more than couple of string utilities.

Upvotes: 1

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