嵌套try catch

Question

我對Java很新，我嵌套Try Catch代碼打印3次！你能告訴我爲什麼嗎？ 我從命令行得到3 int，必須驗證並檢查它們是否在範圍內，並且我正在使用try和catch。但答案打印3次！

// Global Constants 
final static int MIN_NUMBER = 1; 
final static int MAX_PRIME = 10000; 
final static int MAX_FACTORIAL = 12; 
final static int MAX_LEAPYEAR = 4000; 

// Global Variable 
static int a, b, c; 

public static void main(String[] args) { 
    // String[] myNumbers= new String [3]; 

    // int x =Integer.parseInt(args[0]); 
    for (int i = 0; i < args.length; i++) { 
     // System.out.print(args[i]+" "); 
     validateInput(args[0], args[1], args[2]); 

    } 
} 

// Validate User Input 
public static boolean validateInput(String value1, String value2, String value3) { 
    boolean isValid = false; 

    try { 
     try { 
      try { 
       a = Integer.parseInt(value1); 
       if (!withinRange(a, MIN_NUMBER, MAX_PRIME)) { 
        System.out.println(
          "The entered value " + value1 
          + " is out of range [1 TO 10000]."); 
       } 
       isValid = true;   

      } catch (Exception ex) { 
       System.out.println(
         "The entered value " + value1 
         + " is not a valid integer. Please try again."); 
      } 

      b = Integer.parseInt(value2); 
      if (!withinRange(b, MIN_NUMBER, MAX_FACTORIAL)) { 
       System.out.println(
         "The entered value " + value2 
         + " is out of range [1 TO 12]."); 
      } 
      isValid = true; 
     } catch (Exception ex) { 
      System.out.println(
        "The entered value " + value2 
        + " is not a valid integer. Please try again."); 
     } 

     c = Integer.parseInt(value3); 
     if (!withinRange(c, MIN_NUMBER, MAX_LEAPYEAR)) { 
      System.out.println(
        "The entered value " + value3 
        + " is out of range [1 TO 4000]."); 
     } 
     isValid = true; 
    } catch (Exception ex) { 
     System.out.println(
       "The entered value " + value3 
       + " is not a valid integer. Please try again."); 
    } 

    return isValid; 

} 

// Check the value within the specified range 
private static boolean withinRange(int value, int min, int max) { 
    boolean isInRange = true; 

    if (value < min || value > max) { 
     isInRange = false; 
    } 
    return isInRange; 
} 

Answer 1

答案是印刷3次，因爲你已經把validateInput方法調用到for迴路main()，運行它的三個參數的情況下三次。

Answer 2

我建議編寫validateInput方法來驗證單個字符串。爲min和max允許的int值添加兩個參數。

public static boolean validateInput(String value, int minValue, int maxValue) { 
    try { 
     integer intVal = Integer.parseInt(value); 
     if (intVal < minVal || intVal > maxValue) { 
      System.out.println("The entered value " + value 
       + " is out of range [" + minValue + " TO " + maxValue + "]."); 

      return false; 
     } 
    } catch (Exception e) { 
     System.out.println("The entered value " + value 
      + " is not a valid integer. Please try again"); 
     return false; 
    } 
    return true; 
}