xml文件:

 <?xml version="1.0" encoding="GBK"?>

 <phoneinfo>

   <brand name="小米" id="1">

     <type name="MI5"/>

     <type name="NOTE"/>

     <type name="MI5S"/>

   </brand>

   <brand name="华为" id="2">

     <type name="荣耀8"/>

     <type name="荣耀8plus"/>

   </brand>

   <brand name="苹果" id="3">

     <type name="iphone7"/>

     <type1 name="iphone6"/>

   </brand>

 </phoneinfo>

 用dom4j解析xml文件

 package com.hfxt;

 import java.io.File;

 import java.io.FileNotFoundException;

 import java.io.FileOutputStream;

 import java.io.IOException;

 import java.io.OutputStreamWriter;

 import java.util.Iterator;

 import org.dom4j.Document;

 import org.dom4j.DocumentException;

 import org.dom4j.Element;

 import org.dom4j.io.OutputFormat;

 import org.dom4j.io.SAXReader;

 import org.dom4j.io.XMLWriter;

 //dom4j解析xml并且执行(增、删、改、查)操作

 public class dom4jXmlDemo {

     private Document document;

     public static void main(String[] args){

         dom4jXmlDemo domXml = new dom4jXmlDemo();

         domXml.getDom();

         domXml.addPhoneInfo();

         domXml.updatePhoneInfo();

         //domXml.deletePhoneInfo();

         domXml.showPhoneInfo();

     }

     //获取DOM树

     public void getDom(){

         SAXReader reader = new SAXReader();

         try {

             document = reader.read(new File("phoneinfo.xml"));

         } catch (DocumentException e) {

             e.printStackTrace();

         }

     }

     //增加手机信息

     public void addPhoneInfo(){

         //获取根节点元素

         Element element = document.getRootElement();

         //添加brand节点

         Element brand = element.addElement("brand");

         //为brand添加属性并且赋值

         brand.addAttribute("name","苹果");

         //添加type节点

         Element type = brand.addElement("type");

         Element type1 = brand.addElement("type1");

         //为type节点添加name属性并且赋值

         type.addAttribute("name","iphone7");

         type1.addAttribute("name","iphone6");

         saveXml("phoneinfo.xml");

     }

     //删除手机信息

     public void deletePhoneInfo(){

         //获取根节点

         Element element = document.getRootElement();

         Iterator brand = element.elementIterator();

         //遍历获取每个节点信息

         while(brand.hasNext()){

             Element eleBrand = (Element)brand.next();

             //删除name为苹果的brand

             if(eleBrand.attributeValue("name").equals("苹果")){

                 eleBrand.getParent().remove(eleBrand);

             }

         }

         //保存信息

         saveXml("phoneinfo.xml");

     }

     //修改手机信息

     public void updatePhoneInfo(){

         //获取手机信息

         Element element = document.getRootElement();

         Iterator brand = element.elementIterator();

         int id = 0;

         while(brand.hasNext()){

             Element eleBrand = (Element)brand.next();

             id++;

             eleBrand.addAttribute("id",id+"");

         }

         saveXml("phoneinfo.xml");

     }

     //显示手机信息

     public void showPhoneInfo(){

         //获取根节点

         Element element = document.getRootElement();

         Iterator brand = element.elementIterator();

         while(brand.hasNext()){

             Element eleBrand = (Element)brand.next();

             //根据name属性获取对应的值的名字

             System.out.println(eleBrand.attributeValue("name"));

             //获取type节点

             Iterator type = eleBrand.elementIterator();

             //遍历所有type节点

             while(type.hasNext()){

                 Element eleType = (Element)type.next();

                 System.out.println("\t"+eleType.attributeValue("name"));

             }

         }

     }

     //保存信息到xml

     public void saveXml(String path){

         //格式化

         OutputFormat format = OutputFormat.createPrettyPrint();

         //指定字符编码格式

         format.setEncoding("GBK");

         XMLWriter writer = null;

         //将文件按照指定格式输出到指定路径中

         try {

             writer = new XMLWriter(new OutputStreamWriter(new FileOutputStream(path)),format);

             writer.write(document);

         } catch (FileNotFoundException e) {

             e.printStackTrace();

         } catch (IOException e) {

             e.printStackTrace();

         }finally{

             try {

                 //关闭服务

                 writer.close();

             } catch (IOException e) {

                 e.printStackTrace();

             }

         }

     }

 }