java如何判断是否是回文数

//回文数：是一种数字。如：98789, 这个数字正读是98789,倒读也是98789  
//正读倒读一样，所以这个数字就是回文数  
import java.util.Scanner;  
public class HuiWenShu {  
public static void main(String[] args) {  
    Scanner sc = new Scanner(System.in);  
    System.out.println("请输入一个整数：");  
    int num = sc.nextInt();  
    String str1 = num + "";  
    // String str1 = Integer.toString(num);  
    // String str1 = String.valueOf(num);  
    StringBuilder str2 = new StringBuilder(str1);  
    str2.reverse();  
    int count = 0;  
    for (int i = 0; i < str1.length(); i++) {  
        if (str1.charAt(i) != str2.charAt(i)) {  
            System.out.println(str1 + "不是回文数");  
            break;  
        } else {  
            count++;  
        }  
    }  
    if (count == str1.length()) {  
        System.out.println(str1 + "是回文数");  
    }  
}  
}

Scanner in = new Scanner(System.in);
        System.out.println("请输入一个整数N=：");
        int input = in.nextInt();
        int i = 0;
        int sum = 0;
        int record=input;
        while(true){
            i = input%10;
            sum =sum*10+i;
            input /= 10;
            if(input==0) break;
        }
        if(sum==record)System.out.println("是回文");
        else System.out.println("不是回文");