java 使用DOM4J对XML文件进行增删改查操作

源代码：
DOM4j.java

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;
    }
}

Book.java

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;
    }
}

book.xml

<?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>