java使用DOM4J对XML文件进行增删改查操作

package com.zc.homeWork19;

import java.io.FileWriter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

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

import com.zc.homeWork19.Book;

public class DOM4j {
  public static void main(String args[]) throws Exception {
    /**
     * 第一步，得到document对象。
     */
    Document document = getDocument();

    /**
     * 第二步，修改得到的document对象
     */

    /**
     * 首先，读取功能
     */
    List<Book> books = readAllElementsFromXMLDocument(document);
    traverseBooks(books);

    /**
     * 其次，修改功能 修改内容：将id为b002的元素的title改为Java Core，Price改为100.01
     */
    ModifyInformationOfXMLDocument(document);

     /**
     * 再者：实现删除功能 删除内容：删除掉id为book1的元素内容。
     */
     deleteInformationOfXMLDocument(document);

     /**
     * 最后：实现添加i新元素功能 添加内容：id为book3，title内容为：凤姐玉照，price内容为10000.00
     */
     addNewBookToXMLDocument(document);

     /**
     * 第三步：将得到的document对象持久化保存到硬盘（XML）
     */
     writeToNewXMLDocument(document);
  }

  /**
   * 实现了添加新节点：book的功能
   * 
   * @param document
   */
  private static void addNewBookToXMLDocument(Document document) {
    Element root = document.getRootElement();
    Element newBook = root.addElement("book");
    newBook.addAttribute("id", "book3");
    Element title = newBook.addElement("title");
    title.setText("凤姐玉照");
    Element price = newBook.addElement("price");
    price.setText("10000.01");
  }

  /**
   * 该方法实现了使用dom4j的删除元素的功能
   * 
   * @param document
   */
  private static void deleteInformationOfXMLDocument(Document document) {
    Element root = document.getRootElement();
    for (Iterator it = root.elementIterator(); it.hasNext();) {
      Element book = (Element) it.next();
      String id = book.attributeValue("id");
      if ("book1".equals(id)) {
        Element parent = book.getParent();
        parent.remove(book);
      }
    }
  }

  /**
   * 该方法的作用是修改document中的内容 将id为b002的元素的title改为Java Core，Price改为100.01
   * 
   * @param document
   */
  private static void ModifyInformationOfXMLDocument(Document document) {
    Element root = document.getRootElement();
    List books = root.elements();
    for (int i = 0; i < books.size(); i++) {

      Element book = (Element) books.get(i);
      if ("book2".equals(book.attributeValue("id"))) {

        for (Iterator it = book.elementIterator(); it.hasNext();) {
          Element node = (Element) it.next();
          String type = node.getName();
          if ("title".equals(type)) {
            node.setText("JAVA Core");
          }
          if ("price".equals(type)) {
            node.setText("100.01");
          }
        }
      }
    }

    try {
      writeToNewXMLDocument(document);
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }

  /**
   * 遍历集合
   * 
   * @param books
   */
  private static void traverseBooks(List<Book> books) {
    for (Iterator<Book> iterator = books.iterator(); iterator.hasNext();) {
      Book book = iterator.next();
      System.out.println(book);
    }
  }

  /**
   * 该方法实现了对xml文档的读取功能
   * 
   * @param document
   * @return
   */
  private static List<Book> readAllElementsFromXMLDocument(Document document) {
    List<Book> books = new ArrayList<Book>();
    Element root = document.getRootElement();
    List list = root.elements();
    for (int i = 0; i < list.size(); i++) {
      Element book = (Element) list.get(i);
      Book b = new Book();
      String id = book.attributeValue("id");
      List ll = book.elements();
      b.setId(id);
      System.out.println(id);
      for (int j = 0; j < ll.size(); j++) {
        Element element = (Element) ll.get(j);
        if ("title".equals(element.getName())) {
          String title = element.getText();
          b.setTitle(title);
          System.out.println(title);
        }
        if ("price".equals(element.getName())) {
          String price = element.getText();
          double p = Double.parseDouble(price);
          b.setPrice(p);
          System.out.println(price);
        }
      }
      books.add(b);
    }
    return books;
  }

  /**
   * 通过document对象将内存中的dom树保存到新的xml文档。
   * 
   * @param document
   * @throws Exception
   */
  private static void writeToNewXMLDocument(Document document)
      throws Exception {

    XMLWriter writer = new XMLWriter(new FileWriter(
        "src/com/zc/homeWork19/newbooks.xml"));
    writer.write(document);
    writer.close();
  }

  /**
   * 该方法用于得到document对象。
   * 
   * @return
   * @throws Exception
   */
  private static Document getDocument() throws Exception {
    SAXReader sr = new SAXReader();
    Document document = sr.read("src\books.xml");
    return document;
  }
}

package com.zc.homeWork19;

public class Book {
  public String title;
  public double price;
  public String id;

  public String getTitle() {
    return title;
  }

  public void setTitle(String title) {
    this.title = title;
  }

  public double getPrice() {
    return price;
  }

  public void setPrice(double price) {
    this.price = price;
  }

  public String getId() {
    return id;
  }

  public void setId(String id) {
    this.id = id;
  }

  public String toString() {
    return "图书ISBN为：" + id + "  书名为：" + title + "  价格为：" + price;
  }
}

<?xml version="1.0" encoding="UTF-8"?>
<books>
  <book id="book1">
    <title>JAVA编程思想</title>
    <price>80.00</price>
  </book>
  <book id="book2">
    <title>JAVA 编程理论</title>
    <price>100.00</price>
  </book>
</books>