问一下 dom4j 怎么给一个制定节点的 属性赋值?

Question

      SAXReader saxReader = new SAXReader();
    Document document = saxReader.read("urltest.xml");
    List list = document.selectNodes("//UrlList/url" );
     Iterator iter = list.iterator();
             while(iter.hasNext())
              {
             Element ownerElement = (Element)iter.next();
             String url=ownerElement.getText();
             String state= Trycon.request(url)?"true":"false";//
             ownerElement.attributeValue("state",state);//? 怎么给这个节点的state属性定义值? 这条应该是错的!
             System.out.println("...........\n");
      }
   XMLWriter output = new XMLWriter(
     new FileWriter( new File("urltest.xml") ));
   output.write( document );
    output.close();