分数try catch

package tryo6;

import java.util.*;
class MyException extends Exception
{
    MyException()
    {
        
    }
}
class Pan
{
    double fen;
    void setGrade()
    {
        Scanner shu=new Scanner(System.in);
        try
        {
            try
            {
                fen=shu.nextDouble();
                if(fen<0||fen>100) throw new MyException();
            }
            catch(MyException e)//范围情况
            {
                System.out.println("超出范围，请重新输入：");
                setGrade();
            }
            
        }
        catch(Exception e)//其它情况
        {
            System.out.println("不能含有字符，请重新输入");
            setGrade();
        }
    }
    void showGrade()
    {
        if(fen>0&&fen<60) System.out.println("不及格");
        if(fen>60&&fen<=70) System.out.println("及格");
        if(fen>70&&fen<=80) System.out.println("中");
        if(fen>80&&fen<=90) System.out.println("良");
        if(fen>90&&fen<=100) System.out.println("优");
    }
}
public class grate {
    public static void main(String args[])
    {
        System.out.print("请输入0~100之间的分数：");
        Pan ru=new Pan();
        ru.setGrade();
        ru.showGrade();
    }
}