Swap two digits in a integer

public class Solution {
    public static void main(String[] args) {
        int n = 123456;
        System.out.println(swap(n, 2, 4));
    }
    public static int swap(int n, int i, int j) {
        int len = 0, temp = n;
        while (temp > 0) {
            len ++;
            temp /= 10;
        }
        int digit1 = getDigit(n, i, len);
        int digit2 = getDigit(n, j, len);
        int base1 = 1, base2 = 1;
        for (int k = i; k < len - 1; k++) {
            base1 *= 10;
        }
        for (int k = j; k < len - 1; k++) {
            base2 *= 10;
        }
        return n - digit1 * base1 - digit2 * base2 + digit2 * base1 + digit1 * base2;
    }

    public static int getDigit(int n, int i, int len) {
        int base = 1;
        for (int k = i; k < len - 1; k++) {
            base *= 10;
        }
        return (n / base) % 10;
    }
}