dom4j xml 添加一个节点，指点位置添加节点
http://www.cnblogs.com/yesun/archive/2009/03/16/1413559.html

Element elemBbody = (Element)objXml.selectSingleNode("//body");
if(elemBbody == null)
elemBbody = objXml.getRootElement();
List elements = elemBbody.content();
List listRadioByName = objXml.selectNodes("//input[@type='checkbox' and @name='"+objName+"']");

//插入节点到指定位置
elements.add(elements.indexOf(listRadioByName.get(0)),elemSelect);
elemBbody.setContent(elements);




Element element = doc.getRootElement();
Element responseCodeElement =element.addElement("responseCode");
responseCodeElement.setText(FAILRESPONSECODE);