(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);
     }
 }