Question

System.out.print("What kind of array do you want to create?\n1. Integer Array\n2. Double Array\n3. String Array\nYour Answer: ");
String input;
int num1 = 0;
try {
    input = s.next();
    num1 = Integer.parseInt(input);
    while (num1 > 3 || num1 < 1) {
        System.out.print("Please enter one of the three available options.\nYour Answer: ");
        input = s.next();
        num1 = Integer.parseInt(input);
    }
} catch (InputMismatchException e) {
    System.out.println("Do not enter a letter/special character");
}

因此，我基本上是在向用户提出一个问题，询问他要创建哪种数组。但是，当我尝试破坏它并放入Char / String时，直到出现错误，程序退出。

Answer 1

在while循环内添加try-catch块。否则，异常将在循环之后被捕获，并且当您处理异常（在catch块中）时，您将继续执行流程，而无需要求用户重试。

但这不是导致您出现问题的原因。如果您只想打印错误并继续，则应将代码切换为nextInt()，而不是next()和parseInt()。这样，异常将是正确的，并且将更易于阅读。（当前，当您尝试将String解析为Int而不是输入异常时，您可能会得到NumberFormatException －如果您要那样做，请更改尝试捕获的异常）

int num1 = 0;
try {
    num1 = s.nextInt();
    while (num1 > 3 || num1 < 1) {
        System.out.print("Please enter one of the three available options.\nYour Answer: ");
        num1 = s.nextInt();
    }
} catch (InputMismatchException e) {
    System.out.println("Do not enter a letter/special character");
}

Answer 2

s.next()从String读取Scanner。因此，如果您输入非数字的String，则不会抛出InputMismatchException。相反，当尝试将Integer.parseInt解析为NumberFormatException时，String会抛出int，而您不会捕获该异常。

您可能想尝试这样的事情：

Scanner s = new Scanner (System.in);
System.out.print("What kind of array do you want to create?\n1. Integer Array\n2. Double Array\n3. String Array\nYour Answer: ");
String input;
int num1 = 0;
input = s.next();
try {
  num1 = Integer.parseInt(input);
}
catch (NumberFormatException numEx) {
  System.out.println("Do not enter a letter/special character");
}
while (num1 > 3 || num1 < 1) {
  System.out.print("Please enter one of the three available options.\nYour Answer: ");
  input = s.next();
  try {
    num1 = Integer.parseInt(input);
  }
  catch (NumberFormatException numEx) {
    System.out.println("Do not enter a letter/special character");
  }
}

为什么即使我有catch语句，为什么仍然收到InputMissmatchException

2 个答案: