public static String toString(URL url) throws IOException {
        return toString(url, Charset.defaultCharset());
    }
Gets the contents at the given URL.

@param url The URL source.
@return The contents of the URL as a String.
@throws IOException if an I/O exception occurs.
@since 2.1
pay-java-common/src/main/java/com/egzosn/pay/common/util/IOUtils.java