package TaskOfJavabooksCap2;
import java.util.Scanner;

public class areaAndVolumeOfaCylinder {
   
    public static void main(String[] args) {
        
        // create a scanner object
        Scanner input = new Scanner(System.in);
        
        //Prompt user to enter 2 numbers of a cylinder
        System.out.print("Enter the radius and length of a cyllinder ");
        
        double num1 = input.nextDouble();
        double num2 = input.nextDouble();
        
        double area = num1*num1*3.14;
        System.out.println("The area is "+ area);
        System.out.println("The area is "+ area*num2 );
        
    }

}
请问各位大佬们，我这个scanner输入为什么只能针对整数，对于小数就会出现 InputMismatchException

各位大佬帮我看看呗。抱错是从 double num1 = input.nextDouble();开始报错的，搞了几天了也不知道为啥错的。。

"C:\Program Files\Java\jdk-15.0.2\bin\java.exe" "-javaagent:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.3.2\lib\idea_rt.jar=58290:C:\Program Files\JetBrains\IntelliJ IDEA Community Edition 2020.3.2\bin" -Dfile.encoding=UTF-8 -classpath C:\Users\Administrator\IdeaProjects\TaskOfJavaBooks\out\production\hellojava TaksOfJavabook.AreaAndVolumenOfaCylinder
Enter the radius and length of a cyllinder 5.5 12.0
Exception in thread "main" java.util.InputMismatchException
    at java.base/java.util.Scanner.throwFor(Scanner.java:939)
    at java.base/java.util.Scanner.next(Scanner.java:1594)
    at java.base/java.util.Scanner.nextDouble(Scanner.java:2564)
    at TaksOfJavabook.AreaAndVolumenOfaCylinder.main(AreaAndVolumenOfaCylinder.java:21)

Process finished with exit code 1

就是这个错误，我一个大佬朋友说我这个可能是IDEA没有配置好的问题。。。

破案了！ 如果确定数据类型没有错误的话可以把ScannerSyntax：
                     Scanner input = new Scanner(System.in);
增添为以下语句：
            Scanner input = new Scanner(System.in).useLocale(Locale.US);
这样应该就不会报错了，这还是俺在Github一个大佬上面看到的解决方法，希望对大家有用。

感觉和电脑某种未知的配置有关，我同学电脑也是没问题的我的就不行。