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Program: How to validate password using regular expression?


Description:

The below given example shows how to validate a password using regular expression. Here this regular expression allows must contain one digit, one lower case char, one upper case char, some special chars, length should be within 6 to 15 chars.


Code:
package com.java2novice.regex;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class MyPasswordValidate {

private static Pattern pswNamePtrn = 
		Pattern.compile("((?=.*\\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%]).{6,15})");
	
	public static boolean validatePassword(String userName){
		
		Matcher mtch = pswNamePtrn.matcher(userName);
		if(mtch.matches()){
			return true;
		}
		return false;
	}
	
	public static void main(String a[]){
		System.out.println("Is 'java2novice' a valid password? "
							+validatePassword("java2novice"));
		System.out.println("Is 'gabbarsingh' a valid password? "
							+validatePassword("gabbarsingh"));
		System.out.println("Is 'Java2NOVICE$' a valid password? "
							+validatePassword("Java2NOVICE$"));
		System.out.println("Is '234aBc#' a valid password? "
							+validatePassword("234aBc#"));
	}
}

Output:
Is 'java2novice' a valid password? false
Is 'gabbarsingh' a valid password? false
Is 'Java2NOVICE$' a valid password? true
Is '234aBc#' a valid password? true
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  2. Simple java regex using Pattern and Matcher classes.
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  13. How to split a string using regular expression?
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About Author

I'm Nataraja Gootooru, programmer by profession and passionate about technologies. All examples given here are as simple as possible to help beginners. The source code is compiled and tested in my dev environment.

If you come across any mistakes or bugs, please email me to [email protected].

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Reference: Java™ Platform Standard Ed. 7 - API Specification | Java™ Platform Standard Ed. 8 - API Specification | Java is registered trademark of Oracle.
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