如何仅从键盘输入整数输入，如果输入无效，我该如何再次询问用户？ [英] How can I take only integer input from keyboard and if input is invalid how do I ask user again?

问题描述

嗨专家.. !!



我想从用户那里获得整数值作为java（控制台应用程序）中的输入。如果用户给出任何字符串值意味着它必须再次询问输入有效的整数。如何将整数作为输入值。



例如：



输入整数值：



S



对不起..输入无效。请提供有效的参赛作品..



我试试这段代码：



import java.util。*;

import java.io. *;





class vvvv

{



public static void main（String [] args）

{

String input = null;

int number = 0;

try

{

BufferedReader bufferedReader = new BufferedReader（new InputStreamReader（System.in） ）;

input = bufferedReader.readLine（）;

number = Integer.parseInt（输入）;

}

catch（NumberFormatException ex）

{

System.out.println（不是数字！）;

}

}



}



但我想要求用户再次输入输入..

这就是我想要的。任何人都可以帮助我..

提前致谢。

Hi experts..!!

I want to get only integer value from the user as input in java(Console Application). If user give any string value mean it must ask again enter valid integer number. How can i get the integer as input value.

For example:

Enter the integer value:

S

Sorry.. Invalid entry. Please give valid entry..

I try this code:

import java.util.*;
import java.io.*;


class vvvv
{

public static void main(String[] args)
{
String input = null;
int number = 0;
try
{
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
input = bufferedReader.readLine();
number = Integer.parseInt(input);
}
catch (NumberFormatException ex)
{
System.out.println("Not a number !");
}
}

}

But i want ask to the user give the input again..
This what i want. Any one can help me please..
Thanks in advance.

推荐答案

尝试这个并根据您的需要进行调整：

try this and adapt it to suit your need:

package com.peterleow;

import java.util.Scanner;

public class Test1 {

    public static void main(String[] args) {

        Scanner sc=new Scanner(System.in);
        int number = 0;
        boolean isMismatched;
        do {
            isMismatched = false;
            try
            {
                System.out.println("Please input an integer\n");

                String usrInput=sc.next();

                number = Integer.parseInt(usrInput);

            }
            catch(NumberFormatException ex)
            {
                isMismatched = true;
                System.out.println("This is not an integer\n");
            }
        } while (isMismatched);

        System.out.println("This is an integer\n");
        System.out.println("You have entered " + number);
        sc.close();

    }

}

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