package cn.itcast.dom4j;import java.io.FileWriter;import java.io.IOException;import java.util.List;import org.dom4j.Document;import org.dom4j.DocumentException;import org.dom4j.Element;import org.dom4j.Node;import org.dom4j.io.OutputFormat;import org.dom4j.io.SAXReader;import org.dom4j.io.XMLWriter;public class DOM4JTest {    public static void main(String[] args) throws DocumentException, IOException {        xPathDemo3();    }          /**     * 使用XPath查找节点 找第二本书的书名     * @throws DocumentException     */    public static void xPathDemo3() throws DocumentException {        // 解析器        SAXReader saxReader =  new SAXReader();        // 解析文档        Document document = saxReader.read("src/book.xml");        // 获取所有 书名 节点        @SuppressWarnings("unchecked")        List
     
       elementsList = document.selectNodes("//书名");        System.out.println(elementsList.get(3).getText());                  // 直接找到某本书的书名        Node node = document.selectSingleNode("//书名[@id='b1']");        System.out.println(node.getText());    }          /**     * 查询第一本书     * @throws DocumentException     */    public static void demo1() throws DocumentException {        // 创建解析器        SAXReader saxReader = new SAXReader();        // 解析文档        Document document = saxReader.read("src/book.xml");        // 先获得根节点        Element rooteElement = document.getRootElement();        // 查找根节点下的节点        String text = rooteElement.element("书").element("书名").getText();        // 打印输出        System.out.println(text);    }    /**     * 添加元素     * @throws DocumentException     * @throws IOException     */    public static void add() throws DocumentException, IOException {        // 创建解析器        SAXReader saxReader = new SAXReader();        // 解析文档        Document document = saxReader.read("src/book.xml");        // 获得根节点        Element rootElement = document.getRootElement();        // 找到要添加的节点        rootElement.element("书").addElement("书名").setText("武当剑法");        // 回写 完美格式        OutputFormat outputFormat = OutputFormat.createPrettyPrint();        /*// 回写 压缩格式        OutputFormat outputFormat = OutputFormat.createCompactFormat();*/        outputFormat.setEncoding("UTF-8");        XMLWriter writer = new XMLWriter(new FileWriter("src/book.xml"), outputFormat);        writer.write(document);        writer.close();    }          /**     * 修改元素：把 葵花宝典 改成 武当剑法     * @throws DocumentException     * @throws IOException     */    public static void modified() throws DocumentException, IOException {        // 创建解析器        SAXReader saxReader = new SAXReader();        // 解析文档        Document document = saxReader.read("src/book.xml");        // 获得根节点        Element rooElement = document.getRootElement();        // 修改        rooElement.element("书").element("书名").setText("武当剑法");                  // 回写 完美格式        OutputFormat outputFormat = OutputFormat.createPrettyPrint();        outputFormat.setEncoding("UTF-8");        XMLWriter xmlWriter = new XMLWriter(new FileWriter("src/book.xml"), outputFormat);        xmlWriter.write(document);        xmlWriter.close();    }          /**     * 删除第一本书的书名     * @throws DocumentException     * @throws IOException     */    public static void delete() throws DocumentException, IOException {        // 解析器        SAXReader reader = new SAXReader();        // 解析文档        Document document = reader.read("src/book.xml");        // 获得根节点        Element root = document.getRootElement();        // 获得第一本书这个节点        Element element = root.element("书").element("书名");        // 删除书名        element.getParent().remove(element);                  // 回写 完美格式        OutputFormat outputFormat = OutputFormat.createPrettyPrint();        outputFormat.setEncoding("UTF-8");        XMLWriter xmlWriter = new XMLWriter(new FileWriter("src/book.xml"), outputFormat);        xmlWriter.write(document);        xmlWriter.close();    }}