java - 验证字符串(PPS 编号)

Question

好的，我正在尝试验证一个字符串(在本例中为 PPS 编号)。我似乎无法让它正常工作。

问题是:

Each Irish citizen is allocated a PPS number once they reach the age of 18 that is unique to them and used for taxation purposes. A valid PPS number will have exactly 8 or 9 characters in total. It will begin with exactly 7 digits and end with one or two uppercase letters. So, for example, 1234567A would be considered a valid PPS number, as would 7863456RT, but 6478TY*%& and 8768086b would both be considered invalid PPS numbers.

package Assess2013Two;
import java.util.Scanner;
public class Group3Solution {
    public static void main(String[] args)
    {
        int index = 0;
        char ch;
        Scanner input = new Scanner(System.in);

        System.out.print("Please enter your PPS number: ");
        String ppsNumber = input.nextLine();

        if(ppsNumber.length() >= 8 && ppsNumber.length() <= 9){
            if(ppsNumber.charAt(7) >= 'A' && ppsNumber.charAt(7) <= 'Z' && ppsNumber.charAt(8) >= 'A' && ppsNumber.charAt(8) <= 'Z')
            {
                if(ppsNumber.length() == 8) {
                    ch = ppsNumber.charAt(index);
                    while(index < ppsNumber.length() && ch >= '0' && ch <= '9'){
                        index++;
                        if(index < ppsNumber.length())
                            ch = ppsNumber.charAt(index);
                    }
                    if(index == ppsNumber.length())
                        System.out.println("You entered a valid PPS number.");
                    else
                        System.out.println("Invalid PPS number!! At least one of the first 7 characters were not digits.");
                }else {
                    ch = ppsNumber.charAt(index);
                    while(index < ppsNumber.length()-2 && ch >= '0' && ch <= '9'){
                        index++;
                        if(index<ppsNumber.length()-2)
                            ch = ppsNumber.charAt(index);
                    }
                    if(index == ppsNumber.length()-2)
                        System.out.println("You entered a valid PPS number.");
                    else
                        System.out.println("Invalid PPS number!! At least one of the first 7 characters were not digits.");
                }


            }else
                System.out.println("Invalid PPS number!! The second-last or last, or both, were not uppercase letters");
        }else
            System.out.println("Invalid PPS number!! It must contain at least 8 to 9 characters.");

        input.close();
    }
}

Answer 1

对于这些类型的问题，我更喜欢使用正则表达式。

if(ppsNumber.matches("\\d{7}[A-Z]{1,2}"))
{ 
  // valid
}
else
{
  //invalid
}