使用dom4j解析xml

package xml;

import org.dom4j.*;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.List;

public class Dom4jDemo {
    public static void main(String[] args) {
        Dom4jDemo dom4jDemo = new Dom4jDemo();
        dom4jDemo.parserXml("S_1.xml");
        dom4jDemo.createXml("hello.xml");
    }

    // https://www.tutorialspoint.com/java_xml/java_dom4j_create_document.htm
    public void createXml(String fileName) {
        try {
            Document document = DocumentHelper.createDocument();

            Element root = document.addElement("cars");
            Element supercarElement = root.addElement("supercars").addAttribute("company", "Ferrai");
            supercarElement.addElement("carname").addAttribute("type", "Ferrari 101").addText("Ferrari 101");

            // Pretty print the document to System.out
            OutputFormat format = OutputFormat.createPrettyPrint();
            XMLWriter writer;
            writer = new XMLWriter(System.out, format);
            writer.write(document);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void parserXml(String fileName) {

        try {
            SAXReader saxReader = new SAXReader();

            Document document = saxReader.read(new File(fileName));

            Node rootElement = document.getRootElement();
            // 获取节点名
            System.out.println(rootElement.getName());

            // 使用 xpath 来选择节点
            // xpath 语法 https://www.tutorialspoint.com/java_xml/java_xpath_parser.htm
            List<Node> nodeList = document.selectNodes("/hierarchy/node/node/node/node/node");

            // 获取属性值，可以转型为 Element，这里 Element 接口继承自 Node 接口
            // Node 节点不仅仅是Element，也可以是 文本节点
            Node node = nodeList.get(0);
            Element element = (Element) node;

            System.out.println(element.attributeValue("resource-id"));
            // 获取属性值，也可以直接用 xpath 获取
            System.out.println(node.valueOf("@resource-id"));

        } catch (DocumentException e) {
            System.out.println(e.getMessage());
        }
    }
}