我的java学习之路-基础-DOM4J

package cn.bxt.oop.xml;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.OutputStream;

import java.io.OutputStreamWriter;

import java.io.UnsupportedEncodingException;

import java.util.Iterator;

import org.dom4j.Document;

import org.dom4j.DocumentException;

import org.dom4j.Element;

import org.dom4j.io.SAXReader;

/*

 *（1）从外界导入包：右键---》 Build Path---》Configure Build Path---》select "Library" tab--->Add External Jars

 *(2) SAXReader :SAX:Simple API for XML;

 *DOM:在内存中创建文档树；内存占用多，适合小的xml文档；

 *SAX:不是创建文档树，以事件驱动，用字节流，一边读一边解析；内存占用少；

 * 

 * 

 */

import org.dom4j.io.XMLWriter;

public class DOM4j {

public static void main(String[] args) throws DocumentException, IOException {

//1.解析文档；

SAXReader reader=new SAXReader();

Document document=reader.read("e:\\books.xml");

//add(document);

//check(document);

//update(document);

delete(document);

        save(document);

}

public static void add(Document document){

//2.add;

Element books=document.getRootElement();//books找到

Element book=books.addElement("book");//在books下添加一个元素， 

Element title=book.addElement("title");//book下添加一个title节点

Element price=book.addElement("price");

title.setText("巴黎圣母院");//设置title名字

price.setText(String.valueOf(38.9));

}

public static void delete(Document document){

Element books=document.getRootElement();

Iterator<Element> it=books.elementIterator();

while(it.hasNext()){

Element book=it.next();

Iterator<Element> itSub=book.elementIterator();

while(itSub.hasNext()){

Element bField=itSub.next();

if("title".equals(bField.getName())&&"北京".equals(bField.getText())){

books.remove(book);

}

}

}

}

public static void update(Document document){

Element books=document.getRootElement();

Iterator<Element> it=books.elementIterator();

while(it.hasNext()){

Element book=it.next();

Iterator<Element> itSub=book.elementIterator();

while(itSub.hasNext()){

Element bField=itSub.next();

if("title".equals(bField.getName())&&"巴黎圣母院".equals(bField.getText())){

bField.setText("三国演义");

}

}

}

}

public static void check(Document document){

Element books=document.getRootElement();

Iterator<Element> it=books.elementIterator();

while(it.hasNext()){

Element book=it.next();

Iterator<Element> itSub=book.elementIterator();

while(itSub.hasNext()){

Element bField=itSub.next();

System.out.println(bField.getName()+" "+bField.getText());

}

}

}

public static void save(Document document) throws IOException{

//3.save;

OutputStream os=new FileOutputStream("e:\\books.xml");

OutputStreamWriter osw=new OutputStreamWriter(os, "utf-8");

XMLWriter writer=new XMLWriter(osw);

writer.write(document);

writer.close();

}

}