Java輸入不匹配異常處理

Question

我正在處理輸入輸出異常處理問題，我正在爲類編寫庫存管理程序。我現在正在處理的選項是添加一個客戶。首先，他們根據客戶是批發還是零售來選擇1或2。如果他們不小心輸入了一個非int值，我想停止該程序。儘管我的try-catch，我仍然得到一個輸入不匹配異常這裏是我的代碼。

 int i = 0; 


     try 
     { 
     System.out.println("Please indicate if customer is wholesale or retail. Type 1 for wholesale or 2 for retail"); 
     i = scan.nextInt(); 
     } 



     catch (InputMismatchException e) 
     { 
     System.out.println("You did not input a valid value. Please enter an Integer value between 1 and 2"); 


     } 


     while (i<1 || i>2) 
     { 
      System.out.println("You did not enter a valid value. Please enter an integer between 1 and 2"); 
      i = scan.nextInt(); 
     } 


    // The data validation previously provided was not running correctly so I changed the logic around 


     if (i == 2) 
     { 
      next.setType("Retail"); 
      System.out.println("The customer is Retail"); 
      System.out.println(""); 

     } 
     else if (i == 1) 
     { 
      next.setType("Wholesale"); 
      System.out.println("The customer is Wholesale"); 
      System.out.println(""); 

     } 

Answer 1

你應該移動的try/catch內循環：

int i = 0; 

while (i < 1 || i > 2) 
{ 
    try 
    { 
     System.out.println("Please indicate if customer is wholesale or retail. Type 1 for wholesale or 2 for retail"); 
     i = scan.nextInt(); 
    } 
    catch (InputMismatchException e) 
    { 
     System.out.println("You did not input a valid value. Please enter an Integer value between 1 and 2"); 
     scan.next(); 
    } 
} 
... 

在異常處理程序會吃他們進入任何無效的輸入的scan.next()，否則你到nextInt()下一次調用將失敗不管什麼。