code: public static Element getEle(Element ele, String xpath) {
          XPathFactory factory = XPathFactory.newInstance();
          XPath xp = factory.newXPath();
          try {
              XPathExpression expression = xp.compile(xpath);
              return (Element) expression.evaluate(ele, XPathConstants.NODE);
          }
          catch (XPathExpressionException e) {
              throw Lang.wrapThrow(e);
          }
  
      }
docs: 从一个 XML 元素开始，根据一条 XPath 获取一个元素
  
  @param ele
  XML 元素
  @param xpath
  要获取的元素的 XPath
  @return 元素，null 表示不存在