架构师训练营第十一周作业

import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class checkCredentials {
    public static boolean checkPassword(String userId, String pwdPlainText, String pwdEncryptedText) {
        if (userId == null || pwdEncryptedText == null || pwdPlainText == null) {
            return false;
        }
        return pwdEncryptedText.equals(encode(userId, pwdPlainText, "MD5"));
    }
    private static String encode(String userId, String plainText, String hashAlgorithm) {
        // encryption algorithm
        String concatenatedInput = userId + plainText;
        byte[] plainTextWithSaltBytes = concatenatedInput.getBytes();
        try {
            MessageDigest md = MessageDigest.getInstance(hashAlgorithm);
            md.update(plainTextWithSaltBytes);
            byte[] encodedInput = md.digest();
            BigInteger bigInt = new BigInteger(1, encodedInput);
            StringBuilder hashText = new StringBuilder(bigInt.toString(16));
            // Now we need to zero pad it if you actually want the full 32 chars.
            while(hashText.length() < 32 ){
                hashText.insert(0, "0");
            }
            return new String(hashText);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return null;
    }
    public static void main(String[] args) {
        String userID = "admin";
        String plainText = "carmelo";
        String encryptedText = "7225cf3eab8ce407bcb5376e2a2f2028";
        if (checkPassword(userID, plainText, encryptedText)) {
            System.out.println("Password Match");
        } else {
            System.out.println("Username or Password Error!");
        }
    }
}