code: public static String evaluate(String xpath, String html) throws XPathExpressionException,
              ParserConfigurationException {
          HtmlCleaner hc = new HtmlCleaner();
          TagNode tn = hc.clean(html);
          Document document = new DomSerializer(new CleanerProperties()).createDOM(tn);
          XPath xPath = XPathFactory.newInstance().newXPath();
          return xPath.evaluate(xpath, document);
      }
docs: XPath解析HTML内容
  
  @param xpath xpath表达式
  @param html html内容
  
  @return 解析结果
  
  @throws XPathExpressionException 异常
  @throws ParserConfigurationException 异常