Extracting Number from URL in Java via Regex

Question

Take URL http://www.abc.com/alpha/beta/33445566778899/gamma/delta

i need to return the number 33445566778899 (with forward slashes removed, number is of variable length but between 10 & 20 digits)

Simple enough (or so i thought) except everything I've tried doesn't seem to work but why?

Pattern pattern = Pattern.compile("\\/([0-9])\\d{10,20}\\/");
        Matcher matcher = pattern.matcher(fullUrl);
        if (matcher.find()) {
            return matcher.group(1);
        }

Answer 1

Try this one-liner:

String number = url.replaceAll(".*/(\\d{10,20})/.*", "$1");