dom4j解析xml文档（增删查改）

package cn.itcast.dom4j;

import java.awt.print.Book;

import java.io.FileOutputStream;

import java.io.FileWriter;

import java.io.OutputStreamWriter;

import java.util.List;

import org.dom4j.Document;

import org.dom4j.DocumentException;

import org.dom4j.DocumentHelper;

import org.dom4j.Element;

import org.dom4j.io.OutputFormat;

import org.dom4j.io.SAXReader;

import org.dom4j.io.XMLWriter;

import org.junit.Test;

public class Demo1 {

//读取xml文档第二本书的，<书名>JavaScript网页开发</书名>

public void read() throws Exception{

SAXReader reader = new SAXReader();

Document document = reader.read("src/book.xml");

Element root = document.getRootElement();

Element book = (Element) root.elements("书").get(1);

String value = book.element("书名").getText();

System.out.println(value);

}

//读取xml文档第二本书的，<书名 name="xxx">JavaScript网页开发</书名>

public void read1() throws Exception{

SAXReader reader = new SAXReader();

Document document = reader.read("src/book.xml");

Element root = document.getRootElement();

Element book = (Element) root.elements("书").get(1);

String value = book.element("书名").attributeValue("name");

System.out.println(value);

}

//在第一本书上添加一个新的售价<售价>200元</售价>

public void add() throws Exception{

SAXReader reader = new SAXReader();

Document document = reader.read("src/book.xml");

Element book = document.getRootElement().element("书");

book.addElement("售价").setText("200元");

// OutputFormat format = OutputFormat.createCompactFormat();//紧凑的

// format.setEncoding("gb2312");

// XMLWriter writer = new XMLWriter(new OutputStreamWriter(new FileOutputStream("src/book.xml"),"gb2312"),format);

//这样编码才不会乱码

XMLWriter writer = new XMLWriter(new OutputStreamWriter(new FileOutputStream("src/book.xml"),"UTF-8"));

// XMLWriter writer = new XMLWriter(new FileWriter("src/book.xml"));

// 不管xml文档是什么编码保存的，都会乱码

writer.write( document );

writer.close();

}

//在第一本书上的指定位置添加一个新的售价<售价>200元</售价>

public void add2() throws Exception{

SAXReader reader = new SAXReader();

Document document = reader.read("src/book.xml");

Element book = document.getRootElement().element("书");

List list = book.elements();

Element price = DocumentHelper.createElement("售价");

price.setText("300元");

OutputFormat format = OutputFormat.createPrettyPrint();

format.setEncoding("UTF-8");

XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"));

writer.write(document);

writer.close();

}

public void delete() throws Exception{

SAXReader reader = new SAXReader();

Document document = reader.read("src/book.xml");

Element price = document.getRootElement().element("书").element("售价");

price.getParent().remove(price);

OutputFormat format = OutputFormat.createPrettyPrint();

format.setEncoding("UTF-8");

XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"));

writer.write(document);

writer.close();

}

//改

@Test

public void update() throws Exception{

SAXReader reader = new SAXReader();

Document document = reader.read("src/book.xml");

Element book = (Element) document.getRootElement().elements("书").get(1);

book.element("作者").setText("徐文艳");

OutputFormat format = OutputFormat.createPrettyPrint();

format.setEncoding("UTF-8");

XMLWriter writer = new XMLWriter(new FileOutputStream("src/book.xml"));

writer.write(document);

writer.close();

}

}