Regular expression for password (at least 2 digits and one special character and minimum length 8)

Question

I have been searching for regular expression which accepts at least two digits and one special character and minimum password length is 8. So far I have done the following:

Answer 1

There is no reason, whatsoever, to implement all rules in a single regex. Consider doing it like thus:

Pattern[] pwdrules = new Pattern[] {
    Pattern.compile("........"),   // at least 8 chars
    Pattern.compile("\d.*\d"),     // 2 digits
    Pattern.compile("[-!"§$%&/()=?+*~#'_:.,;]") // 1 special char
  }

String password = ......;
boolean passed = true;

for (Pattern p : pwdrules) {
    Matcher m = p.matcher(password);
    if (m.find()) continue;
    System.err.println("Rule " + p + " violated.");
    passed = false;
}

if (passed) { .. ok case.. }
else { .. not ok case ... }

This has the added benefit that passwort rules can be added, removed or changed without effort. They can even reside in some ressource file.

In addition, it is just more readable.