如何以更具体的方式处理NumberFormatException？ [英] how to handle NumberFormatException in more specific way?

问题描述

我想以更特定的方式处理NumberFormatException。
输入以下内容时，尝试分配除整数以外的任何内容时，会发生此异常：

I want to handle NumberFormatException in more specific way. This exception occurs, when it tries assign anything but an integer, when the following is entered:

1. string


2. 字符


3. 空输入


4. 双数

1. string
2. character
3. empty input
4. double number

根据输入的内容，我想显示一条正确的消息，例如

Depending on what was entered I want to display a proper message, like

您已经输入了字符串，请输入整数

you've entered string, please enter an integer

或

value不能为空，请输入一个整数值

value can't be null, please enter an integer value

下面的代码捕获 NumberFormatException 一般。

我想知道是否有办法包含更多catch子句。

I wonder is there a way to include more catch clauses.

    import java.util.Scanner;

    public class TestException {

        static int input;
        static Scanner scan = new Scanner(System.in);

        public static void main(String[] args) {
            System.out.println("Enter an integer number: ");

            try {
                input = Integer.parseInt(scan.next());
                System.out.println("You've entered number: " + input);
            } catch (NumberFormatException e) {
                System.out.println("You've entered non-integer number");
                System.out.println("This caused " + e);
            }
        }
    }

推荐答案

首先从用户那里获取输入，然后尝试将其转换为整数。

First take the input from the user and after that try to convert it to integer.

    static int input;
    static Scanner scan = new Scanner(System.in);

    public static void main(String[] args) {
        System.out.println("Enter an integer number: ");

        String inputString = scan.next();

        try {
            input = Integer.parseInt();
            System.out.println("You've entered number: " + input);
        } catch (NumberFormatException e) {
            if(inputString.equals("") || inputString == null) {
                System.out.println("empty input"); 
            } else if(inputString.length == 1) {
                System.out.println("char input");
            } else {
                System.out.println("string input");
            }
        }
    }

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