Document   oResult   =       m_serviceGateway.doRequest(oRequest);  
   
    httpServletResponse.getWriter().println("<?xml   version='1.0'   encoding='"+CoreConfigFactory.getEncoding()+"'?>");  
    httpServletResponse.getWriter().println(new   String(oResult.getRootElement().asXML().getBytes("ISO8859-1"),"gb2312"));

//
DefaultDocument   doc   =   new   DefaultDocument();//DocumentHelper.createDocument();  
          doc.setXMLEncoding("GBK");  

//String   xml   =     doc.asXml();  
  String   xml   =   xml.replaceFisrt("UTF-8","GB2312");

DefaultDocument   doc   =   new   DefaultDocument();  
          //DocumentHelper.createDocument();  
          doc.setXMLEncoding("gb2312");  

多种解决方案