特殊形式的字符串輸入驗證

Question

我正在嘗試除了僱傭號碼XXX-L，其中x是範圍0-9中的一個數字，並且L是範圍爲A-M的一個字母。我試圖讓這個代碼工作。但我無法輸入有效的輸入。

import java.util.Scanner; 
import java.util.InputMismatchException; 

public class ObjectOrinetPrograming 
{ 
    public static void main(String [] args) 
    { 
     Scanner input = new Scanner (System.in); 
     System.out.println("Please Enter elements: "); 
     String employeenumber = input.nextLine(); 
     while (employeenumber.length() != 5) 
     { 
      System.out.println("invalid input; lenght, Try again:"); 
      employeenumber = input.nextLine(); 
     } 


      while (employeenumber.charAt(4) != ('A'|'B'|'C'|'D'|'E'|'F'|'G'|'H'|'I'|'J'|'K'|'L'|'M')) 
      { 
       System.out.print("invalid input; charrecter match, try again:"); 
       employeenumber = input.nextLine(); 
      } 


     while (employeenumber.charAt(0) == '-') 
     { 
      System.out.println("Invalid Input; form, try again:"); 
      employeenumber = input.nextLine(); 
     } 
     } 

} 

Answer 1

您應該使用matches，這將允許您驗證所有輸入：

import java.util.Scanner; 
import java.util.InputMismatchException; 
public class ObjectOrinetPrograming 
{ 
    public static void main(String [] args) 
    { 
     Scanner input = new Scanner (System.in); 
     System.out.println("Please Enter elements: "); 
     String employeenumber = input.nextLine(); 

     while (!employeenumber.matches("[0-9]{3}-[A-Ma-m]")) { 
      System.out.println("invalid input; lenght, Try again:"); 
      employeenumber = input.nextLine(); 
     } 

    } 

} 

Answer 2

您可以使用正則表達式來匹配輸入employeenumber。

public static void main(String[] args) { 
    Scanner input = new Scanner(System.in); 
    System.out.println("Please Enter elements: "); 
    String employeenumber = input.nextLine(); 
    while (!employeenumber.matches("[0-9]{3}-[A-M]")) { 
     System.out.println("invalid input; lenght, Try again:"); 
     employeenumber = input.nextLine(); 
    } 

    System.out.println("Your employee id is " + employeenumber); 

}