package org.db;

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

import org.dom4j.Attribute;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import org.dom4j.XPath;
import org.dom4j.io.OutputFormat;
import org.dom4j.io.SAXReader;
import org.dom4j.io.XMLWriter;

public class Demo {
 /**
     * 建立一个XML文档,文档名由输入属性决定
     * @param filename 需建立的文件名
     * @return 返回操作结果, 0表失败, 1表成功
     */
    public static int createXMLFile(String filename){
       /** 返回操作结果, 0表失败, 1表成功 */
       int returnValue = 0;
       /** 建立document对象 */
       Document document = DocumentHelper.createDocument();
       /** 建立XML文档的根books */
       Element booksElement = document.addElement("books");
       /** 加入一行注释 */
       booksElement.addComment("This is a test for dom4j, holen, 2004.9.11");
       /** 加入第一个book节点 */
       Element bookElement = booksElement.addElement("book");
       /** 加入show属性内容 */
       bookElement.addAttribute("show","yes");
       /** 加入title节点 */
       Element titleElement = bookElement.addElement("title");
       /** 为title设置内容 */
       titleElement.setText("Dom4j Tutorials");
      
       /** 类似的完成后两个book */
       bookElement = booksElement.addElement("book");
       bookElement.addAttribute("show","yes");
       titleElement = bookElement.addElement("title");
       titleElement.setText("Lucene Studing");
       bookElement = booksElement.addElement("book");
       bookElement.addAttribute("show","no");
       titleElement = bookElement.addElement("title");
       titleElement.setText("Lucene in Action");
      
       /** 加入owner节点 */
       Element ownerElement = booksElement.addElement("owner");
       ownerElement.setText("O'Reilly");
      
       try{
           /** 将document中的内容写入文件中 */
        OutputFormat format = OutputFormat.createPrettyPrint();
        format.setEncoding("UTF-8");
           XMLWriter writer = new XMLWriter(new FileWriter(new File(System.getProperty("user.dir")+"/test.xml")),format);
           writer.write(document);
           writer.close();
           /** 执行成功,需返回1 */
           returnValue = 1;
       }catch(Exception ex){
           ex.printStackTrace();
       }
             
       return returnValue;
    }
    public static void main(String[] args) {
     //createXMLFile("test.xml");
    }
   
    /**
     * 修改XML文件中内容,并另存为一个新文件
     * 重点掌握dom4j中如何添加节点,修改节点,删除节点
     * @param filename 修改对象文件
     * @param newfilename 修改后另存为该文件
     * @return 返回操作结果,0表失败,1表成功
     */
    public static  int ModiXMLFile(String filename,String newfilename){
       int returnValue = 0;
       try{
        System.out.println(filename);
           SAXReader saxReader = new SAXReader();
           Document document = saxReader.read(new File(filename));
           /** 修改内容之一: 如果book节点中show属性的内容为yes,则修改成no */
           /** 先用xpath查找对象 */
           XPath xpath = (XPath) DocumentHelper.createXPath("/books/book/@show");
           List list = xpath.selectNodes(document);
           Iterator iter = list.iterator();
           while(iter.hasNext()){
              Attribute attribute = (Attribute)iter.next();
              if(attribute.getValue().equals("yes")){
                  attribute.setValue("no");
              }  
           }
          
           /**
            * 修改内容之二: 把owner项内容改为Tshinghua
            * 并在owner节点中加入date节点,date节点的内容为2004-09-11,还为date节点添加一个属性type
            */
           list = document.selectNodes("/books/owner" );
           iter = list.iterator();
           if(iter.hasNext()){
              Element ownerElement = (Element)iter.next();
              ownerElement.setText("Tshinghua");
              Element dateElement = ownerElement.addElement("date");
              dateElement.setText("2004-09-11");
              dateElement.addAttribute("type","Gregorian calendar");
           }
          
           /** 修改内容之三: 若title内容为Dom4j Tutorials,则删除该节点 */
           list = document.selectNodes("/books/book");
           iter = list.iterator();
           while(iter.hasNext()){
              Element bookElement = (Element)iter.next();
              Iterator iterator = bookElement.elementIterator("title");
              while(iterator.hasNext()){
                  Element titleElement=(Element)iterator.next();
                  if(titleElement.getText().equals("Dom4j Tutorials")){
                     bookElement.remove(titleElement);
                  }
              }
           }         
          
           try{
              /** 将document中的内容写入文件中 */
           OutputFormat format = OutputFormat.createPrettyPrint();
           format.setEncoding("UTF-8");
              XMLWriter writer = new XMLWriter(new FileWriter(new File(newfilename)),format);
              writer.write(document);
              writer.close();
              /** 执行成功,需返回1 */
              returnValue = 1;
           }catch(Exception ex){
              ex.printStackTrace();
           }
       }catch(Exception ex){
           ex.printStackTrace();
       }
        return returnValue;
    }
  }