如何使用dom拼接xml字符串（标准方式）

如何使用dom拼接xml字符串（标准方式） .
package com.my.test;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
public class XmlGroup {
/**
* 返回applogin接口的请求xml yes
* @param guid
* @param guidpwd
* @return String xml信息
*/
public static String getRquestXml(String guid, String guidpwd)
{

Document requestDoc = DocumentHelper.createDocument();
Element root = requestDoc.addElement("message");
Element headElement = root.addElement("head");
headElement.addElement("guid").addText(guid);
Element paramsElement = root.addElement("body").addElement("params");
paramsElement.addElement("pwd").addText(guidpwd);
paramsElement.addElement("callbackurl");

return root.asXML();
}

/**
* 返回searchemployee接口的请求xml
* @param appid
* @param tag
* @param accounts

* @return String
*/
public String getRequestSearchEmployeeXml(String appid, String tag, String accounts)
{

Document requestDoc = DocumentHelper.createDocument();
Element root = requestDoc.addElement("message");
Element headElement = root.addElement("head");
headElement.addElement("appid").addText(appid);
headElement.addElement("tag").addText(tag);
headElement.addElement("accounts").setText(accounts);
Element paramsElement = root.addElement("body").addElement("params");
paramsElement.addElement("condition").setText(accounts);
paramsElement.addElement("pagecount").setText("20");
paramsElement.addElement("pagenum").setText("1");
return root.asXML();
}

public static void main(String agrs[])
{
//test
String xml=getRquestXml("zhangyi","123");
System.out.println(xml);

//test
String xml2=getRquestXml("mobile","ads324sdsa4sf3w");
System.out.println(xml2);

}
}