Question

因此，让我们假设我们有这个循环，以字符串的形式从用户那里获得输入。通过该输入，我们想要做的是设置一组验证，以检查是否满足某些条件。如果满足所有这些条件，它将完成相关操作。然而;如果它没有，它会告诉他们错误并重新启动该过程。

我的问题是验证字符串中字母的存在（或不存在）。我有这个程序，对于其中一个验证，我需要检查整个字符串。如果字符串中没有至少一个不是字母的字符，我想暂停操作并解释需要非字母字符。

问题在于我不确定如何在if循环中的表达式中复制它。这是我到目前为止所拥有的。

public static changePassword() // Method that runs through the process of changing the password. 
 {
      // Retrieving the current and new password from the user input.
      System.out.println("Welcome to the change password screen.");
      Scanner keyboard = new Scanner(System.in);
      System.out.print("Please enter your current password: ");
      String currentPassword = keyboard.nextLine();
      System.out.print("Please enter the new password: ");
      String newPassword1 = keyboard.nextLine();
      System.out.print("Please enter the new password again: ");
      String newPassword2 = keyboard.nextLine();

      // Validating the new password entry.
      if (newPassword1.equals(newPassword2)) // Checking to see if the new password was entered exactly the same twice.
      {
        if (newPassword1.length() >= 6) // Checking to see if the new password has 6 or more characters.
        {
           if (**some expression**) // Checking to see if the password has at least one non-letter character.
           {
              currentPassword = newPassword1 // If all conditions are met, it sets the current password to the password entered by the user.
           }
           else // If there isn't a non-letter character, it informs the user and restarts the process.
           {
              System.out.println("The new password must have a non-letter character.");
              changePassword();
           }
        }
        else // If there is less than 6 characters, it informs the user and restarts the process.
        {
           System.out.println("The new password can not be less than 6 characters.");
           changePassword();
        }
      }
      else // If the new passwords don't match, it informs the user and restarts the process.
      {
        System.outprintln("The passwords must match.");
        changePassword();
      }


 }

Answer 1

假设“letter”是指A-Z中的英文字符，a-z，只是遍历字符串，如果遇到int值超出字母范围的字符，则返回true。

public static boolean containsNonLetter(String s){
    for(int i = 0; i < s.length(); i++){
        int ind = (int)s.charAt(i);
        if(ind < 65 || (ind > 90 && ind < 97) || ind > 122)
            return true;
    }
    return false;
}

Answer 2

我假设通过信件你的意思是字母。如果使用正则表达式模式，您可以拥有非常干净的代码，并且您可以根据需要更新模式。要了解详情，请查看Java Pattern。这是代码。

private static final Pattern APLHA = Pattern.compile("\\p{Alpha}");

public static boolean hasLetter(String input) {

    return APLHA.matcher(input).find();
}

在字符串中搜索循环中的非字母字符

2 个答案: