Java - Write code to check if a string is Integer by radix

Requirements

Write code to check if a string is Integer by radix

Demo

//package com.book2s;

public class Main {
    public static void main(String[] argv) {
        String s = "book2s.com";
        System.out.println(isInteger(s));
    }/* w  w  w  . j a  v a2s . c  om*/

    public static boolean isInteger(String s) {
        return isInteger(s, 10);
    }

    public static boolean isInteger(String s, int radix) {
        if (s.isEmpty())
            return false;
        for (int i = 0; i < s.length(); i++) {
            if (i == 0 && s.charAt(i) == '-') {
                if (s.length() == 1)
                    return false;
                else
                    continue;
            }
            if (Character.digit(s.charAt(i), radix) < 0)
                return false;
        }
        return true;
    }
}