用的try/catch InputMismatch異常掙扎，並從一個數組

Question

我嘗試做以下檢索數據：

• 調用創建Array 100隨機生成的整數的方法。
• 調用提示用戶輸入數組的索引位置並返回輸入值的方法。如果用戶輸入的值不是有效整數，則拋出「輸入不匹配異常」，提示用戶出現問題，並允許他們輸入正確的整數或退出程序。

---

package latest; 
import java.util.Scanner; 
import java.util.InputMismatchException; 
import java.util.Random; 

public class Latest 
{ 
    private static int[] randomInteger; 

    public static void main(String[] args) 
    { 
     Scanner input = new Scanner(System.in); 
     int indexPosition = 0;  
     randomInteger = new int[100]; 
     Random rand = new Random(); 
     for (int i=0; i<randomInteger.length;i++)   
      randomInteger[i] = rand.nextInt(); 

     while (indexPosition < 0 || indexPosition > 100) 
     {   
      try 
      { 
       // get array index position 
       System.out.println ("Hello, please enter an integer for the array index position: "); 
       indexPosition = input.nextInt(); 
      } 
      catch (InputMismatchException e) 
      { 
       System.out.println ("You did not input a valid value. Please enter an Integer value between 0 and 100"); 
       indexPosition = input.nextInt(); 
      } 
      {  
       System.out.println ("You did not input a valid value. Please enter an Integer value between 0 and 100"); 
       indexPosition = input.nextInt(); 
       System.out.println (randomInteger[indexPosition]); 
      } 
     } 
    } 
} 

我的問題是代碼編譯，但不輸出任何東西和IDE是說indexPosition - "Assigned value never used"

編輯：英格麗在評論作品的代碼完全然而，如果你輸入一個有效的整數沒有發現任何異常，它只是崩潰

Answer 1

你幾乎在那裏。試試以下版本。

package latest; 

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

public class Latest { 

private static int[] randomInteger; 

public static void main(String[] args) { 
    int indexPosition = 0; 
    Scanner input = new Scanner(System.in); 
    randomInteger = new int[100]; 
    Random rand = new Random(); 
    for (int i = 0; i < randomInteger.length; i++) 

     randomInteger[i] = rand.nextInt(); 

    System.out 
      .println("Hello, please enter an integer for the array index position: "); 
    do { 
     try { 
      // get array index position 
      indexPosition = input.nextInt(); 
     } catch (InputMismatchException e) { 
      System.out 
        .println("You did not input a valid value. Please enter an Integer value between 0 and 100"); 
      input.nextLine(); 
      continue; 
     } catch (Exception e) { 
      System.out 
        .println("You did not input a valid value. Please enter an Integer value between 0 and 100"); 
      input.nextLine(); 
      continue; 
     } 
     if (indexPosition < 0 || indexPosition > 100) { 
      System.out 
        .println("You did not input a valid value. Please enter an Integer value between 0 and 100"); 
     } 

    } while (indexPosition < 0 || indexPosition > 100); 
    System.out.println(randomInteger[indexPosition]); 
    input.close(); 
} 
}