Java Swing Register Form Password Weakness Conditions

Question

I want to make a registration system in java. It's in a very good progress. I only have one specific problem. The password weakness. I made that, tha password must be longer than 8 character with a simple

if(password.getText().length() > 8) { error message }

I also put a condition just like that:

if(... < 8 || !(password.getText().contains("1"))) { error message }

But with this condition it only accept the password if your password for example: asdfghjk1 So I tried the condition with a lot of || condition like !....contains("2")..|| !..contains("9")

But with theese conditions it only works when the password is: 123456789 But what i really want to do is a password, that longer than 8 character, contains at least one capital and at least one number. Is that any way to do that? By the way I use Java swing.

For best practice you should use a [JPasswordField](https://docs.oracle.com/javase/tutorial/uiswing/components/passwordfield.html) — David Kroukamp, Dec 13 '20 at 11:27

score 0 · Answer 1 · answered Dec 13 '20 at 09:59

You can do that by using regex, but I don't know how. but this should work:

this is where you validate your password: String passwordString = password.getText();

if (passwordString.Length() > 8 && checkCapital(passwordString) && checkDigit(passwordString)){ valid password }

else { error message }

this is checkCapital I used ascii codes:

private static boolean checkCapital(String string) {
    for (char c : string.toCharArray()) {
        int code = (int) c;
        if (code >= 65 && code <= 90) 
            return true;
    }
    return false;
}

this is checkDigit:

private static boolean checkDigit(String string) {
    for (int i = 0; i < 10; i++) {
        if (string.contains("" + i))
            return true;
    }
    return false;
}

score 0 · Accepted Answer · answered Dec 13 '20 at 16:16

The best way to solve this problem is to use Regex. Here I am making an example for you of how to use regex to check password.

import java.util.regex.*; 
class GFG { 
  
    // Function to validate the password. 
    public static boolean
    isValidPassword(String password) 
    { 
  
        // Regex to check valid password. 
        String regex = "^(?=.*[0-9])"
                       + "(?=.*[a-z])(?=.*[A-Z])"
                       + "(?=.*[@#$%^&+=])"
                       + "(?=\\S+$).{8,20}$"; 
  
        // Compile the ReGex 
        Pattern p = Pattern.compile(regex); 
  
        // If the password is empty 
        // return false 
        if (password == null) { 
            return false; 
        } 
  
        // Pattern class contains matcher() method 
        // to find matching between given password 
        // and regular expression. 
        Matcher m = p.matcher(password); 
  
        // Return if the password 
        // matched the ReGex 
        return m.matches(); 
    } 
  
    // Driver Code. 
    public static void main(String args[]) 
    { 
  
        // Test Case 1: 
        String str1 = "Thuans@portal20"; 
        System.out.println(isValidPassword(str1)); 
  
        // Test Case 2: 
        String str2 = "DaoMinhThuan"; 
        System.out.println(isValidPassword(str2)); 
  
        // Test Case 3: 
        String str3 = "Thuan@ portal9"; 
        System.out.println(isValidPassword(str3)); 
  
        // Test Case 4: 
        String str4 = "1234"; 
        System.out.println(isValidPassword(str4)); 
  
        // Test Case 5: 
        String str5 = "Gfg@20"; 
        System.out.println(isValidPassword(str5)); 
  
        // Test Case 6: 
        String str6 = "thuan@portal20"; 
        System.out.println(isValidPassword(str6)); 
    } 
}

Output: true false false false false false

Also you can refer to similar topics by following the link below:

Regex Java for password

Java Swing Register Form Password Weakness Conditions

2 Answers2