org.w3c.dom.Document对象与org.dom4j.Document对象互相转换

我现在是如下的写法,请教效率高一点的（重点是org.dom4j.Document   ->   org.w3c.dom.Document的转换），感谢。  
 

/**  
        *   org.w3c.dom.Document   ->   org.dom4j.Document  
        *   @param   doc   Document(org.w3c.dom.Document)  
        *   @return   Document  
        */  
      public   static   Document   parse(org.w3c.dom.Document   doc)   throws   Exception   {  
          if   (doc   ==   null)   {  
              return   (null);  
          }  
          org.dom4j.io.DOMReader   xmlReader   =   new   org.dom4j.io.DOMReader();  
          return   (xmlReader.read(doc));  
      }  
   
      /**  
        *   org.dom4j.Document   ->   org.w3c.dom.Document  
        *   @param   doc   Document(org.dom4j.Document)  
        *   @throws   Exception  
        *   @return   Document  
        */  
      public   static   org.w3c.dom.Document   parse(Document   doc)   throws   Exception   {  
          if   (doc   ==   null)   {  
              return   (null);  
          }  
          java.io.StringReader   reader   =   new   java.io.StringReader(doc.asXML());  
          org.xml.sax.InputSource   source   =   new   org.xml.sax.InputSource(reader);  
          javax.xml.parsers.DocumentBuilderFactory   documentBuilderFactory   =  
                  javax.xml.parsers.DocumentBuilderFactory.newInstance();  
          javax.xml.parsers.DocumentBuilder   documentBuilder   =   documentBuilderFactory.  
                  newDocumentBuilder();  
          return   (documentBuilder.parse(source));  
      }