(补)Java解析XML之dom4j

上次记得忘了记最流行的dom4j方法了,用的还是上次的那个XML文件

 

注:需要添加dom4j.jar文件

 

package com.xujingyang.dom4j;


import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.Node;
import org.junit.Test;

import com.xujingyang.utils.dom4jUtil;

public class dom4jTest {

    /**
     * 获取指定节点的内容
     */
    @Test
    public void testDom4j() {
        try {
            Document document = dom4jUtil.getDocument("src/books.xml");
            // 获取根节点
            Element rootElement = document.getRootElement();
            // 获取根节点的子节点集合的第一个节点
            Element element = (Element) rootElement.elements().get(0);
            // 获取对应子节点的文本
            String text = element.element("price").getText();
            System.out.println(text);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    //==================递归遍历所有子节点的文本开始======================================
    @Test
    public void test2() {
        try {
            Element rootElement = dom4jUtil.getDocument("src/books.xml")
                    .getRootElement();
            treeWalk(rootElement);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public static void treeWalk(Element element) {
        //获取子节点个数
        int nodeCount = element.nodeCount();
        
        //遍历子节点
        for (int i = 0; i < nodeCount; i++) {
            //获取第i个子节点
            Node node = element.node(i);
            if (node instanceof Element) {
                //如果仍然是节点就递归
                treeWalk((Element) node);
            } else {
                //不是就打印节点内容
                String text = node.getStringValue();
                System.out.println(text);
            }
        }
    }
    
    //===================递归遍历所有子节点的文本结束================================================
    
    /**
     * 添加新子节点
     */
    @Test
    public  void test3(){
        try {
            Document document = dom4jUtil.getDocument("src/books.xml");
            // 获取根节点
            Element rootElement = document.getRootElement();
            Element element = (Element) rootElement.elements("book").get(0);
            //添加子节点信息
            element.addElement("特价").setText("21");
            //写入源文件
            dom4jUtil.writeDocument(document);
            
            
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
    /**
     * 添加同级新节点
     */
    @Test
    public  void test4(){
        try {
            Document document = dom4jUtil.getDocument("src/books.xml");
            // 获取根节点
            Element rootElement = document.getRootElement();
            Element element = (Element) rootElement.elements("book").get(0);
            
            Element createElement = DocumentHelper.createElement("新价");
            createElement.setText("31");
            //向子节点的指定位置添加新节点
            element.elements().add(2, createElement);
            //写入源文件
            dom4jUtil.writeDocument(document);
            
            
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
    /**
     * 删除指定的节点
     */
    @Test
    public void test5(){
        try {
            Document document = dom4jUtil.getDocument("src/books.xml");
            // 获取根节点
            Element rootElement = document.getRootElement();
            //找到子节点
            Element element = (Element) rootElement.elements("book").get(0);
            //找到要删除的节点
            Element tejia = element.element("特价");
            //删除
            element.remove(tejia);
            //写入文件
            dom4jUtil.writeDocument(document);
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
    

}

 

 程序用到的工具类:

package com.xujingyang.utils;

import java.io.FileOutputStream;

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

public class dom4jUtil {

    /**
     * 得到Document对象
     * 
     * @param path
     * @return
     * @throws Exception
     */
    public static Document getDocument(String path) throws Exception {
        SAXReader reader = new SAXReader();
        return reader.read(path);
    }

    /**
     * 写入XML
     * @param document
     * @throws Exception
     */
    public static void writeDocument(Document document) throws Exception {
        OutputFormat format = OutputFormat.createPrettyPrint();
        format.setEncoding("UTF-8");
        XMLWriter xmlWriter = new XMLWriter(new FileOutputStream(
                "src/books.xml"), format);
        xmlWriter.write(document);
    }
}