com.sun.org.apache.xerces.internal.dom.DeferredTextImpl cannot be cast to org.w3c.dom.Element

代码

 List<book> list = new ArrayList<book>();
        Document doc = new DOCUntil().getDocument("src/ww/t/qp/books.xml");
        Element root = doc.getDocumentElement();
        NodeList books = root.getElementsByTagName("book");
        for (int i = 0; i < books.getLength(); i++) {
            Element n1 = (Element) books.item(i);
            NodeList nodeList = n1.getChildNodes();
            String a1 = null;
            String a2 = null;
            String a3 = null;
            for (int j = 0; j < nodeList.getLength(); j++) {
                Element e2 = (Element) nodeList.item(j);
                if (e2.getNodeName().equals("author")) {
                    a1 = e2.getTextContent();
                }
                if (e2.getNodeName().equals("title")) {
                    a2 = e2.getTextContent();
                }
                if (e2.getNodeName().equals("description")) {
                    a3 = e2.getTextContent();
                }
            }
            list.add(new book(new Integer(n1.getAttribute("id")), a1, a2, a3));
        }
        System.out.println(list.toString());

报错

报错代码

  Element e2 = (Element) nodeList.item(j);

分析

        getChildNodes获取的是全部子节点,在 xml 文档节点前存在 回车,制表符等 都会占用一个节点Node( 如#text )，这一类Node是无法转为Element，会抛com.sun.org.apache.xerces.internal.dom.DeferredTextImpl cannot be cast to org.w3c.dom.Element。

解决方案

1.直接使用Node对象进行操作

2.在强转前进行 if 判断标签