把一个XML字符串转换为一个XML文档对象

/***
    * 把一个XML字符串转换为一个XML文档对象
    * @param returnXML : XML字符串
    * @return Document xml文档对象
    * @throws Exception
    */
   private org.w3c.dom.Document getDocument(String returnXML) throws BOException
   {
      org.w3c.dom.Document doc = null;
      if (returnXML != null && returnXML.length() > 0)
      {
         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
         dbf.setNamespaceAware(true);
         DocumentBuilder db = null;
         try
         {
            db = dbf.newDocumentBuilder();
         }
         catch (ParserConfigurationException pce)
         {
            pce.printStackTrace();
         }
         try
         {
            StringReader rd = new StringReader(returnXML);
            InputSource in = new InputSource(rd);
            doc = db.parse(in);

         }
         catch (IOException ioe)
         {
            ioe.printStackTrace();
         }
         catch (SAXException saxe)
         {
            saxe.printStackTrace();
         }
      }
      return doc;
   }