@Override
    public String select(Element element) {
        List<Element> elements = selectElements(element);
        if (CollectionUtils.isEmpty(elements)) {
            return null;
        }
        return getValue(elements.get(0));
    }
CSS selector. Based on Jsoup.

@author code4crafter@gmail.com <br>
@since 0.1.0
webmagic-core/src/main/java/us/codecraft/webmagic/selector/CssSelector.java