public void parseDocument2(Document document){
		//get root element
		Element rootElement = document.getDocumentElement();

		//traverse child elements
		NodeList nodes = rootElement.getChildNodes();
		for (int i=0; i < nodes.getLength(); i++)
		{
			Node node = nodes.item(i);
			if (node.getNodeType() == Node.ELEMENT_NODE) {
				Element child = (Element) node;
				//process child element
			}
		}

		NodeList nodeList = rootElement.getElementsByTagName("book");
		if(nodeList != null)
		{
			for (int i = 0 ; i < nodeList.getLength(); i++)
			{
				Element element = (Element)nodeList.item(i);
				String id = element.getAttribute("id");
				System.out.println(id);
			}
		}
	}