XML解析(DOM)

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public class DOM_Parser {

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    public static void main(String[] args) {

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        try {

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            String path = DOM_Parser.class.getClassLoader()

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                .getResource("books.xml").getPath();

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            // 获取文档对象

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            Document doc = getDocumentByPath(path);

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            // 遍历文档对象树（加载xml文档在内存中形成的文档对象树）

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            // 获取xml文档根元素

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            Element root = doc.getDocumentElement();

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            BookVO vo = new BookVO();

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            vo.setId("004");

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            vo.setName("JAVA未眠者");

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            // 创建一个新的book元素

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            createBookElement(doc, root, vo);

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            // 遍历元素

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//          iteratorElement(root);

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            iteratorElement2(root);

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        } catch (ParserConfigurationException e) {

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            e.printStackTrace();

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        } catch (SAXException e) {

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            e.printStackTrace();

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        } catch (IOException e) {

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            e.printStackTrace();

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        }

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    }

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    /**

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     * 遍历元素

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     *

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     * @param ele

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     */

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    private static void iteratorElement(Element ele) {

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        // 获取根元素下子元素（book元素）

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        NodeList bookNodes = ele.getChildNodes();

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        for (int i = 0; i < bookNodes.getLength(); i++) {

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            Node bookNode = bookNodes.item(i);

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            // 判断当前节点是否为元素节点

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            if (bookNode.getNodeType() == Node.ELEMENT_NODE) {

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                Element childEle = (Element) bookNode;

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                // 根据元素上的属性名获取到对应的属性值

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                if (childEle.hasAttribute("id")) {

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                    System.out.print("id = " + childEle.getAttribute("id")

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                            + " ");

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                    // 遍历book元素下的子元素

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                    iteratorElement(childEle);

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                } else {

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                    System.out.print(childEle.getNodeName() + " = "

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                            + childEle.getTextContent() + " ");

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                    if ("author".equals(childEle.getNodeName())) {

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                        System.out.println();

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                    }

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                }

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            }

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        }

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    }

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    /**

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     * 通过getElementsByTagName()方法遍历文档对象树中元素

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     *

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     * @param root

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     */

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    private static void iteratorElement2(Element root) {

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         //获取所有book元素节点

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        NodeList books = root.getElementsByTagName("book");

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        NodeList name = root.getElementsByTagName("name");

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        NodeList type = root.getElementsByTagName("type");

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        NodeList price = root.getElementsByTagName("price");

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        NodeList author = root.getElementsByTagName("author");

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        for (int i = 0; i < books.getLength(); i++) {

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            Element bookEle = (Element)books.item(i);

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            System.out.print("id = " + bookEle.getAttribute("id"));

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            Element nameEle = (Element)name.item(i);

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            System.out.print("  name = " + nameEle.getTextContent());

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            System.out.println();

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        }

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    }

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    /**

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     * 创建新的book元素对象

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     *

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     * @param doc

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     * @param root

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     */

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    private static void createBookElement(Document doc, Element root, BookVO vo) {

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        // 向文档对象树上添加新book子元素

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        // 创建新的book元素

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        Element book = doc.createElement("book");

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        book.setAttribute("id", vo.getId());

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        // 创建book元素下的子元素

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        Element name = doc.createElement("name");

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        name.setTextContent(vo.getName());

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        Element price = doc.createElement("price");

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        Element type = doc.createElement("type");

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        Element author = doc.createElement("author");

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        // 构建元素之间层次关系

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        book.appendChild(name);

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        book.appendChild(price);

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        book.appendChild(type);

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        book.appendChild(author);

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        root.appendChild(book);

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    }

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    /**

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     * 根据xml文档路径，获取解析xml文档对应的文档对象

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     *

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     * @param path

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     * @return

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     * @throws ParserConfigurationException

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     * @throws SAXException

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     * @throws IOException

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     */

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    private static Document getDocumentByPath(String path)

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            throws ParserConfigurationException, SAXException, IOException {

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        // 获取DOM解析器工厂对象

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        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();

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        // 获取DOM解析器对象

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        DocumentBuilder db = dbf.newDocumentBuilder();

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        // 加载要解析xml文档

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        Document doc = db.parse(path);

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        return doc;

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    }

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}