CODEWITHSUNDEEP
javaregex
Marcos Vasconcelos
Marcos Vasconcelos

Reputation: 18276

Password validation with regex (Has letters & numbers & special).{8,}

I need to know how the regex is for the following case:

I got the following based in other regex:

((?=.*\d)(?=.*[a-z|A-Z])(?=.*[~'!@#$%?\\\/&*\]|\[=()}"{+_:;,.><'-])).{8,}

But it fails for:

qwer!234

Any tips?

Upvotes: 1

Views: 6801

Answers (4)

Visme
Visme

Reputation: 983

Pattern letter = Pattern.compile("[a-zA-z]");  
Pattern digit = Pattern.compile("[0-9]");  
Pattern special = Pattern.compile ("[!@#$%&*()_+=|<>?{}\\[\\]~-]");  
Pattern eight = Pattern.compile (".{8}");  
...  
public final boolean ok(String password) {  
   Matcher hasLetter = letter.matcher(password);  
   Matcher hasDigit = digit.matcher(password);  
   Matcher hasSpecial = special.matcher(password);  
   Matcher hasEight = eight.matcher(password);  
   return hasLetter.find() && hasDigit.find() && hasSpecial.find()  
      && hasEight.matches();  
}

It will works.

Upvotes: 0

Bernhard Barker
Bernhard Barker

Reputation: 55619

With all those special characters, it's moderately likely that you didn't escape everything properly.

You said Java right? This prints true:

String regex = "((?=.*\\d)(?=.*[a-zA-Z])(?=.*[~'!@#$%?\\\\/&*\\]|\\[=()}\"{+_:;,.><'-])).{8,}";
System.out.println("qwer!234".matches(regex));

But this is quite a bit simpler:

String regex = "(?=.*?\\d)(?=.*?[a-zA-Z])(?=.*?[^\\w]).{8,}";

Upvotes: 1

Tim Pietzcker
Tim Pietzcker

Reputation: 336378

In a Java regex, you need to double the backslashes because of string escaping rules:

Pattern regex = Pattern.compile("^(?=.*\\d)(?=.*[a-zA-Z])(?!\\w*$).{8,}");

should work.

Explanation:

^              # Start of string
(?=.*\d)       # Assert presence of at least one digit
(?=.*[a-zA-Z]) # Assert presence of at least one ASCII letter
(?!\w*$)       # Assert that the entire string doesn't contain only alnums
.{8,}          # Match 8 or more characters

Upvotes: 4

Bryan Oakley
Bryan Oakley

Reputation: 386210

Why put this all in a single regular expression? Just make separate functions for each check and your code will be much easier to understand and maintain.

if len(password) > 8 &&
   has_alpha(password) &&
   has_digit(password) &&
    ...

Your business logic is instantly undertandable. Plus, you don't have to modify a tricky regular expression when you want to add some other condition.

Upvotes: 1

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