code: public static Node getNodeByXPath(String expression, Object source) {
  		return (Node) getByXPath(expression, source, XPathConstants.NODE);
  	}
docs: 通过XPath方式读取XML节点等信息<br>
  Xpath相关文章：https://www.ibm.com/developerworks/cn/xml/x-javaxpathapi.html
  
  @param expression XPath表达式
  @param source 资源，可以是Docunent、Node节点等
  @return 匹配返回类型的值
  @since 4.0.9