This example shows how to validate a Password string in Java using regular expression with Regex Pattern and Matcher validation.
Password Regular Expression Pattern:
((?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%]).{6,20})
Whole combination is means, 6 to 20 characters string with at least one digit, one upper case letter, one lower case letter and one special symbol (“@#$%”). This regular expression pattern is very useful to implement a strong and complex password.
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import java.util.regex.Matcher; import java.util.regex.Pattern; public class PasswordValidator { private Pattern pattern; private Matcher matcher; private static final String PASSWORD_PATTERN = "((?=.*\\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%]).{6,20})"; public PasswordValidator() { pattern = Pattern.compile(PASSWORD_PATTERN); } /** * Validate password with regular expression * @param password password for validation * @return true valid password, false invalid password */ public boolean validate(final String password) { matcher = pattern.matcher(password); return matcher.matches(); } } |