class DefQaContentLink implements QaContentLink {

    @Override
    public Model getContent(String contentUrl) {
        Document doc = HtmlDocumentUtil.urlToDocument(contentUrl);
        if (HtmlDocumentUtil.validateDocument(doc)) {
            Model model = new Model();
            model.setQaLink(contentUrl);
            //问题
            Elements elements = doc.select(CONTENT_SELECT);
            model.setQuestion(elements.get(1).text());

            //答案
            elements = doc.select(ANSWER_SELECT);
            model.setAnswer(elements.get(0).text());


            //依据
            elements = doc.select(GIST_SELECT);
            model.setGistLink(elements.get(0).text());
            return model;
        }
        return null;
    }

}