Document document = DocumentHelper.createDocument();
document.setXMLEncoding(ChARSET_UTF_8);

Element root = document.addElement("message");
Element head = root.addElement("head");

head.addElement("field").addAttribute("name"," ").setText("");

Element body = root.addElement("body");
body.addElement("field").addAttribute("name","").setText("");

return document.asXML();

Document document = DocumentHelper.parseText(input);
Element root = document.getRootElement();

Element headElement = root.element("head");
Preconditions.checkArgument(headElement != null,"XML中无head元素");
setData(dataMap,bodyElement);

Element bodyElement = root.element("body");
Preconditions.checkArgument(bodyElement != null,"XML中无body元素;
setData(dataMap,BodyElement);


public void setData(Map<String,Object> dataMap,Element parentElement){

    List<Element> fieldElements = parentElement.elements("field");
    Preconditions.checkArgument((fieldElements != null &&     fieldElements.isEmpty()),"XML缺少field元素");
    
    for(Element fieldElement : fieldElements){
        String name = fieldElement.attributeValue("name");
        String value = StringUtils.trimToNull(fieldElement.getTextTrim()):
        dataMap.put(name,value);
    }
}