检查密码，验证，并再次循环

Question

我有一个问题需要至少 2 个大写字母、至少 3 个小写字母和 1 个数字。

这是确切的问题：

编写一个应用程序，提示用户输入至少包含两个大写字母、至少三个小写字母和至少一位数字的密码。不断提示用户，直到输入有效密码。如果密码有效则显示Valid password；如果不是，请显示密码无效的适当原因，如下所示：

例如，如果用户输入“密码”，您的程序应该输出：您的密码无效，原因如下：大写字母数字

如果用户输入“passWOrd12”，您的程序应该输出：valid password

到目前为止，这是我的编码，我遇到的问题是程序提示用户在输入密码后输入更多密码，但密码不正确。

import java.util.*;

public class ValidatePassword {
    public static void main(String[] args) {
        String inputPassword;
        Scanner input = new Scanner(System.in);
        System.out.print("Password: ");
        inputPassword = input.next();
        System.out.println(PassCheck(inputPassword));
        System.out.println("");
    }

    public static String PassCheck(String Password) {
        String result = "Valid Password";
        int length = 0;
        int numCount = 0;
        int capCount = 0;
        for (int x = 0; x < Password.length(); x++) {
            if ((Password.charAt(x) >= 47 && Password.charAt(x) <= 58)
                    || (Password.charAt(x) >= 64 && Password.charAt(x) <= 91)
                    || (Password.charAt(x) >= 97 && Password.charAt(x) <= 122)) {
            } else {
                result = "Password Contains Invalid Character!";
            }
            if ((Password.charAt(x) > 47 && Password.charAt(x) < 58)) {
                numCount++;
            }
            if ((Password.charAt(x) > 64 && Password.charAt(x) < 91)) {
                capCount++;
            }

            length = (x + 1);
        }
        if (numCount < 2) {
            result = "digits";
        }
        if (capCount < 2) {
            result = "uppercase letters";
        }
        if (numCount < 2 && capCount < 2) {
            result = "uppercase letters digits";
        }

        if (length < 2) {
            result = "Password is Too Short!";
        }
        return (result);
    }
}

Answer 1

你需要一个 while 循环。这将确保您的代码将一直循环直到成功。当它成功时，布尔值变为真并且它不会循环。在 while 循环之后写下你想要发生的任何事情。

public static void main(String[] args) {
    String inputPassword;
    Scanner input = new Scanner(System.in);
    boolean success=false;
    while(!success){

    System.out.print("Password: ");
    inputPassword = input.next();
    System.out.println(PassCheck(inputPassword));
    if(PassCheck(inputPassword).equals("Valid Password")) success = true; 
    System.out.println("");

    } 
  }

Answer 2

您可以通过将 PassCheck 方法的 return 类型更改为布尔结果并使用 Character class 检查大写小写数字字符和计数来实现最后出现每个检查条件，如果通过则结果为 true 否则为 false 并且您可以根据 PassCheck 的结果迭代 do-while方法

public class ValidatePassword {
    public static void main(String[] args) {
        String inputPassword;
        Scanner input = new Scanner(System.in);
        boolean isValidPassword = false;
        
        do {
            System.out.print("Password: ");
            inputPassword = input.next();
            isValidPassword = PassCheck(inputPassword);
            System.out.println("");
        }while(!isValidPassword);
    }
    
    public static boolean PassCheck(String Password) {
        boolean isValid = false;
        String result = "";
        int numCount = 0;
        int capCount = 0;
        int lowCount = 0;
        
        for (int x = 0; x < Password.length(); x++) {
            
            if(Character.isDigit(Password.charAt(x))) {
                numCount++;
            }
            if(Character.isUpperCase(Password.charAt(x))) {
                capCount++;
            }
            
            if(Character.isLowerCase(Password.charAt(x))) {
                lowCount++;
            }
        }
        
        if(numCount >= 1 && capCount >= 2 && lowCount >= 3) {
            result = "Password Valid";
            isValid = true;
        } else {
            isValid = false;
            result = "Password is Invalid: ";
            
            if(Password.length() < 2) {
                result += " Password is Too Short!";
            }
            
            if(numCount < 1) {
                result += " no digit";
            }
            
            if(capCount < 2) {
                result += " at lease 2 Uppercase";
            }
            
            if(lowCount < 3) {
                result += " at lease 3 Lowercase";
            }
        }
        System.out.println(result);
        return isValid;
    }
}

Answer 3

下面是我在 Cengage 平台上运行的完成代码：

import java.util.*;
public class ValidatePassword {
public static void main(String[] args) {
    String inputPassword;
    Scanner input = new Scanner(System.in);
    boolean success=false;
    while(!success){

    System.out.print("Password: ");
    inputPassword = input.next();
    System.out.println(PassCheck(inputPassword));
    if(PassCheck(inputPassword).equals("Valid Password")) success = true; 
    System.out.println("");

    } 
  }

  public static String PassCheck(String Password) {
    String result = "Valid Password";
    int length = 0;
    int numCount = 0;
    int capCount = 0;
    for (int x = 0; x < Password.length(); x++) {
      if ((Password.charAt(x) >= 47 && Password.charAt(x) <= 58) || (Password.charAt(x) >= 64 && Password.charAt(x) <= 91) ||
        (Password.charAt(x) >= 97 && Password.charAt(x) <= 122)) {
      } else {
        result = "Password Contains Invalid Character!";
      }
      if ((Password.charAt(x) > 47 && Password.charAt(x) < 58)) {
        numCount++;
      }
      if ((Password.charAt(x) > 64 && Password.charAt(x) < 91)) {
        capCount++;
      }
      
      length = (x + 1);
    }
    if (numCount < 2) {
      result = "digits";
    }
    if (capCount < 2) {
      result = "uppercase letters";
    }
    if (capCount < 2) {
      result = "uppercase letters";
    }
    if (numCount < 2 && capCount < 2) 
    {
      result = "uppercase letters digits";
    }

    if (length < 2) {
      result = "Password is Too Short!";
    }
    return (result);
  }
}

检查密码，验证，并再次循环

Check password, verify, and loop again

java

passwords

validation

loops