public static List<String> convertToUrls(Collection<Request> requests) {
        List<String> urlList = new ArrayList<String>(requests.size());
        for (Request request : requests) {
            urlList.add(request.getUrl());
        }
        return urlList;
    }
@param url url
@return new url
@deprecated
webmagic-core/src/main/java/us/codecraft/webmagic/utils/UrlUtils.java