首先运行是 0 分。。。 在idea上，输入5和19991，就输出个一个5.一直找不出错误。求指正！谢谢！

package com.athuashan.bean;

import java.util.Scanner;

public class Test01 {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int a = scanner.nextInt();
        int b = scanner.nextInt();
        int revNum = 0;
        //偶数不会是质数
        if(a % 2 == 0){
            a++;
        }
        for(int num = a; num <= b; num += 2){
            int num1 = num;
            //翻转数字
            while (num1 != 0){
                revNum = revNum * 10 + num1 % 10;
                num1 /= 10;
            }
            if(num == revNum){
                boolean flag = true;
                //判断是否为质数
                for (int i = 2; i < num / 2; i++) {
                    if(num % i == 0){
                        flag = false;
                        break;
                    }
                }
                if(flag){
                    System.out.println(num);
                }
            }
        }

    }

}