/*
DOM解析轻松入门（二）--简单的DOM实战
author:shine
*/
以下这个例子，使用xml充当数据库。完成增删改查。
一、准备：
1）需要在“DOM解析轻松入门（一）”中的DOMSerializer类。
2）准备一个xml文件：
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<books>
<book id="1">
<name>Chinese</name>
<description>ChineseBook</description>
</book>

<book id="2">
<name>math</name>
<description>mathBook</description>

</book>

<book id="3">
<name>english</name>
<description>englishBook</description>
</book>
</books>

二、代码：
1）创建一个实体类Book：
package com.shine.vo;

public class Book {
 private String bookId;
 private String bookName;
 private String description;
 public String getBookId() {
  return bookId;
 }
 public void setBookId(String bookId) {
  this.bookId = bookId;
 }
 public String getBookName() {
  return bookName;
 }
 public void setBookName(String bookName) {
  this.bookName = bookName;
 }
 public String getDescription() {
  return description;
 }
 public void setDescription(String description) {
  this.description = description;
 }
 
}

2）使用DAO类BookDAO 进行增、删、改、查
package com.shine.dao;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.ArrayList;

import org.apache.xerces.parsers.DOMParser;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

import com.shine.util.DOMSerializer;
import com.shine.vo.Book;

public class BookDAO {
 private String xmlURI = "D://workplace//test1.xml";

 private DOMParser parser;

 private Document doc;

 private Element root;

 public BookDAO() {
  try {
   DOMParser parser = new DOMParser();
   BufferedReader br = new BufferedReader(new FileReader(xmlURI));
   InputSource inputSource = new InputSource(br);
   parser.parse(inputSource);
   doc = parser.getDocument();
   root = doc.getDocumentElement();
  } catch (SAXException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }

 //主函数中试验一下，（所有方法已经测试过，由于篇幅原因，就测试findAllBooks方法，其他方法就不一一演示了，大家可以试一下）
 public static void main(String[] args) {
  //使用findAllBooks方法
  BookDAO dao = new BookDAO();
  ArrayList list = dao.findAllBooks();
  for(int i=0; i<list.size(); i++) {
   Book book = (Book)list.get(i);
   System.out.println("id="+book.getBookId());
   System.out.println("name="+book.getBookName());
   System.out.println("description="+book.getDescription());
  }
 }

 // 按编号查找book，返回null表示此book不存在, !null表示查找成功。
 public Book findOneBook(String bookId) {
  Book book = null;
  Element rightBook = (Element) this.findRightBook(bookId);
  if (rightBook != null) {
   book = new Book();
   String bookName = rightBook.getElementsByTagName("name").item(0)
     .getTextContent();
   String description = rightBook.getElementsByTagName("description")
     .item(0).getTextContent();
   book.setBookId(bookId);
   book.setBookName(bookName);
   book.setDescription(description);
  }
  return book;
 }

 // 插入book,返回0表示此book已存在，1表示插入成功
 public int insertBook(Book book) {
  int flag = 0;
  Element rightBook = (Element) this.findRightBook(book.getBookId());
  if (rightBook == null) {
   // 增加book元素
   Element bookNode = doc.createElement("book");
   bookNode.setAttribute("id", book.getBookId());
   root.appendChild(bookNode);

   // 增加bookName元素
   Element bookNameNode = doc.createElement("name");
   Text bookNameText = doc.createTextNode(book.getBookName());
   bookNameNode.appendChild(bookNameText);
   bookNode.appendChild(bookNameNode);

   // 增加bookDescription
   Node bookDescriptionNode = doc.createElement("description");
   Text bookDescriptionText = doc
     .createTextNode(book.getDescription());
   bookDescriptionNode.appendChild(bookDescriptionText);
   bookNode.appendChild(bookDescriptionNode);
   this.save();
   flag = 1;
  }
  return flag;

 }

 // 删除book，返回0表示此book不存在，1表示删除成功
 public int removeBook(String bookId) {
  int flag = 0;
  Node node = this.findRightBook(bookId);
  if (node != null) {
   root.removeChild(node);
   flag = 1;
  }
  this.save();
  return flag;
 }

 //更新book，返回0表示此book不存在，1表示更新成功
 public int updateBook(Book book) {
  int flag = 0;
  Element rightBook = (Element) this.findRightBook(book.getBookId());
  if (rightBook != null) {
   rightBook.getElementsByTagName("name").item(0).setTextContent(
     book.getBookName());
   rightBook.getElementsByTagName("description").item(0)
     .setTextContent(book.getDescription());
   this.save();
   flag = 1;
  }
  return flag;
 }

 //查找所有的书籍
 public ArrayList findAllBooks() {
  ArrayList bookList = new ArrayList();
  NodeList nodeList = root.getElementsByTagName("book");
  for(int i=0; i<nodeList.getLength(); i++) {
   Book book = new Book();
   Element bookNode = (Element)nodeList.item(i);
   String bookId = bookNode.getAttributes().getNamedItem("id").getNodeValue();
   String bookName = bookNode.getElementsByTagName("name").item(0).getTextContent();
   String description = bookNode.getElementsByTagName("description").item(0).getTextContent();
   book.setBookId(bookId);
   book.setBookName(bookName);
   book.setDescription(description);
   bookList.add(book);
  }
  return bookList; 
 }

 //根据bookId找到正确的book节点
 public Node findRightBook(String bookId) {
  Node rightBook = null;
  NodeList nodeList = doc.getElementsByTagName("book");
  for (int i = 0; i < nodeList.getLength(); i++) {
   String id = nodeList.item(i).getAttributes().getNamedItem("id")
     .getNodeValue();
   if (id != null && id.equals(bookId)) {
    rightBook = nodeList.item(i);
    break;
   }
  }
  return rightBook;
 }

 // 存入文件
 public void save() {
  try {
   FileWriter fw = new FileWriter(xmlURI);
   BufferedWriter bw = new BufferedWriter(fw);
   DOMSerializer serializer = new DOMSerializer();
   serializer.serialize(doc, bw);
   bw.close();
   fw.close();
  } catch (IOException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }
}

/*
DOM解析轻松入门（三）--.DOM Level 2 Tranversal 和Range    2008-2-17
*/