자바 비밀번호 생성(금융보안원)

import java.util.ArrayList;
import java.util.List;

public class PasswordValidation {

  //220510 nhm,
  public static boolean isPasswordInvalid(String password, String email, String birth, String cellNo, int characterCheckCount) {
    //비밀번호 길이
    if(!isPasswordRange(password)) {
      return false;
    }

    //알파벳 대문자와 소문자, 숫자, 특수문자 중 두 종류 이상 포함
    if(!isContainsPasswordType(password)) {
      return false;
    }

    //계정명· 고유식별번호·생년월일·전화번호 포함 제한
    if(!isContainUniqueNumber(password, email, birth, cellNo)) {
      return false;
    }

    //4자리 이상 연속된 숫자·문자· 특수문자(!,@,#,$ 등) 포함 제한,
    if(!isContinuedCharacter(password, characterCheckCount)) {
      return false;
    }

    //4자리 이상 동일한 숫자·문자·특수문자 포함 제한
    return isCharacterContainsCount(password, characterCheckCount);
  }

  private static boolean isPasswordRange(String password) {
    final int passWordLength = 8;

    //비밀번호 길이 체크
    return passWordLength <= password.length();
  }

  private static boolean isContainsPasswordType(String password) {
    //알파벳 대문자와 소문자, 숫자, 특수문자 중 두 종류 이상 포함
    int passwordLength = password.length();
    int passwordTypeCount = 0;

    //"^[0-9a-zA-Z가-힣]*$";
    final String upperEnglish = "[A-Z]";
    final String lowerEnglish = "[a-z]";
    final String numberCharacter = "[0-9]";
    final String specialCharacter = "[a-zA-Z0-9 ㄱ-ㅎㅏ-ㅣ가-힣]";

    String upper = replaceExpression(password, upperEnglish);
    String lower = replaceExpression(password, lowerEnglish);
    String number = replaceExpression(password, numberCharacter);
    String special = replaceExpression(password, specialCharacter);

    if(passwordLength > upper.length()) {
      passwordTypeCount++;
    }

    if(passwordLength > lower.length()) {
      passwordTypeCount++;
    }

    if(passwordLength > number.length()) {
      passwordTypeCount++;
    }

    if(special.length() > 0) {
      passwordTypeCount++;
    }

    return passwordTypeCount > 1;
  }

  private static String replaceExpression(String password, String pattern) {
    return password.replaceAll(pattern, "");
  }

  private static boolean isContainUniqueNumber(String password, String email, String birth, String cellNo) {
    final String specialCharacter = "[^0-9a-zA-Z]";

    //이메일
    String userEmail = replaceExpression(email.substring(0, email.indexOf("@")), specialCharacter);

    if(password.contains(userEmail)) {
      return false;
    }

    //생년월일
    String userBirth = birth.substring(2);

    if(password.contains(userBirth)) {
      return false;
    }

    //전화번호
    String[] cellNoArray = getCellNoArray(cellNo);

    for (String checkCellNo : cellNoArray) {
      if(password.contains(checkCellNo)) {
        return false;
      }
    }

    return true;
  }

  private static String[] getCellNoArray(String cellNo) {
    final String cellNoRange = "01012345678";

    return  cellNo.length() == cellNoRange.length()
            ? new String[] { cellNo.substring(3, 7), cellNo.substring(7, 11) }
            : new String[] { cellNo.substring(3, 6), cellNo.substring(7, 10) };
  }

  private static boolean isContinuedCharacter(String password, int continueCount) {
    int nowChar = 0;
    int charCount = 0;

    for(char p : password.toCharArray()) {
      if(nowChar != p) {
        charCount = 1;
      } else {
        charCount++;
      }

      if(charCount > 3) {
        break;
      }

      nowChar = p;
    }

    return continueCount > charCount;
  }

  //4자리 이상 동일한 숫자·문자·특수문자 포함 제한
  private static boolean isCharacterContainsCount(String password, int containsCount) {
    List<Character> characterList = new ArrayList<>();

    for(char s : password.toCharArray()) {

      if(characterList.contains(s)) {
        continue;
      }

      characterList.add(s);
      int arrayContainsCount = (int) password.chars().filter(x -> x == s).count();

      if(arrayContainsCount >= containsCount) {
        return false;
      }
    }

    return true;
  }
}