java判断是否是回文数

public class HwTest{  //方法一 public  static boolean isCircleNumber1(int num) {    String temp = String.valueOf(num);    StringBuffer sb = new StringBuffer(temp);    return sb.reverse().toString().equals(temp);  }//方法二 public static boolean isCircleNumber2(int num){       int oldValue = num;       int temp = 0;       while(num > 0){           temp = temp*10 +num%10;            num = num/10;         }       return temp == oldValue;    }//方法三?public static boolean isCircleNumber3(int num){??? boolean flag = true;??? String temp = String.valueOf(num);??? char[] arr =? temp.toCharArray();??? int len =arr.length;??? for(int i=0,j=len-1;i<j;){???? if(arr[i++] == arr[j--]){???? }else{????? flag = false;????? break;???? }??? }?? return flag; }    public static void main(String args[]) {       int num = 12321;        System.out.println(isCircleNumber1(num));       System.out.println(isCircleNumber2(num));       System.out.println(isCircleNumber3(num));   } }

??