反转数字、字符串

public class Test
{
    final static int[] sizeTable = { 9, 99, 999, 9999, 99999, 999999, 9999999, 99999999, 999999999, Integer.MAX_VALUE };

    static int sizeOfInt(int x)
    {
        for (int i = 0;; i++)
            if (x <= sizeTable[i])
                return i + 1;
    }

    public static String reverse(String originStr)
    {
        if (originStr == null || originStr.length() <= 1)
            return originStr;
        return reverse(originStr.substring(1)) + originStr.charAt(0);
    }

    public static Integer reverse(int value)
    {
        if (value < 10)
        {
            return value;
        }
        return (value % 10) * (int)Math.pow(10, sizeOfInt(value) - 1) + reverse(value / 10);
    }

    public static void main(String[] args)
    {
        System.out.println(reverse("helloworld"));
        System.out.println(reverse(123456789));

    }
}