dom4j解析xml文档(增删改查)

 package itcast.dom4j;

 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.util.List;

 import org.dom4j.Document;
 import org.dom4j.DocumentException;
 import org.dom4j.DocumentHelper;
 import org.dom4j.Element;
 import org.dom4j.io.OutputFormat;
 import org.dom4j.io.SAXReader;
 import org.dom4j.io.XMLWriter;
 import org.junit.Test;

 public class Demo {

     // 在第一本书上添加一个新的售价：<price>209yuan</price>
     @Test
     public void add() throws Exception {
         SAXReader reader = new SAXReader();
         Document document = reader.read(new File("src/book.xml"));

         Element book = document.getRootElement().element("书");
         book.addElement("price").setText("209yuan");

         OutputFormat format = OutputFormat.createPrettyPrint();
         format.setEncoding("UTF-8");

         XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),
                 format);
         writer.write(document);
         writer.close();
     }

     @Test
     public void add2() throws Exception {
         SAXReader reader = new SAXReader();
         Document document = reader.read(new File("src/book.xml"));

         Element book = document.getRootElement().element("书");
         List list = book.elements();// bookname/author/price

         Element price = DocumentHelper.createElement("price");
         price.setText("309yuan");

         list.add(2, price);

         OutputFormat format = OutputFormat.createPrettyPrint();
         format.setEncoding("UTF-8");

         XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),
                 format);
         writer.write(document);
         writer.close();
     }

     @Test
     public void delete() throws Exception {
         SAXReader reader = new SAXReader();
         Document document = reader.read(new File("src/book.xml"));

         Element price = document.getRootElement().element("书").element("price");
         price.getParent().remove(price);

         OutputFormat format = OutputFormat.createPrettyPrint();
         format.setEncoding("UTF-8");

         XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),
                 format);
         writer.write(document);
         writer.close();
     }

     @Test
     public void update() throws Exception {
         SAXReader reader = new SAXReader();
         Document document = reader.read(new File("src/book.xml"));

         Element book = (Element) document.getRootElement().elements("书").get(1);
         book.element("editor").setText("zero");

         OutputFormat format = OutputFormat.createPrettyPrint();
         format.setEncoding("UTF-8");

         XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"),
                 format);
         writer.write(document);
         writer.close();
     }

 }

 <?xml version="1.0" encoding="UTF-8"?>

 <书架>
   <书>
     <bookname name="zero">java jiuyepeixunjiaocheng</bookname>
     <editor>zhangxiaoxiang</editor>
     <price>209yuan</price>
   </书>
   <书>
     <bookname name="one">javaWebprogramming</bookname>
     <editor>zero</editor>
     <price>28.00yuan</price>
   </书>
 </书架>