进入黑马day2-解析xml三种方法（3）dom4j解析器

package cn.itheima.dom4j;

import java.io.FileWriter;

importjava.io.IOException;

importjava.util.List;

importorg.dom4j.Document;

importorg.dom4j.DocumentHelper;

importorg.dom4j.Element;

importorg.dom4j.io.OutputFormat;

importorg.dom4j.io.SAXReader;

import org.dom4j.io.XMLWriter;

import org.junit.Test;

public class Demo3 {

//增加元素

@Test

publicvoid add() throws Exception {

SAXReaderread = new SAXReader();

Documentdom = read.read("book.xml");

//在第一本书增加<特价>

ElementbookEle = dom.getRootElement().element("书");

//用DocumentHelper可以创建元素，并设置标签体为10.0元

Elementpri2Ele = DocumentHelper.createElement("特价");

pri2Ele.setText("10.0元");

bookEle.add(pri2Ele);

ListbookList = dom.getRootElement().elements();

//dem4j获取标签的时候帮我们排除了空白标签

ElementbookEle = (Element) bookList.get(0);

StringbookName = bookEle.element("书名").getText();

System.out.println(bookName);

//修改元素标签体

Element pri2Ele = dom.getRootElement().element("书").element("特价");

pri2Ele.setText("9.9元");

//删除标签

Element bookEle = dom.getRootElement().element("书");

Elementpri2Ele = bookEle.element("特价");

bookEle.remove(pri2Ele);

//添加属性

Element bookEle = dom.getRootElement().element("书");

bookEle.addAttribute("出版社", "人民日报");

//更新XML文件

//XMLWriter默认是UTF-8的，所以必须重设输出编码

OutputFormatformat =OutputFormat.createPrettyPrint();

format.setEncoding("gb2312");

XMLWriterwriter = new XMLWriter(new FileWriter("book.xml"),format);

writer.write(dom);

writer.close();

}

附：利用dom4j中的DocumentHelper类创建xml文件

@Test

publicvoid creatDocument() throws Exception{

Documentdom = DocumentHelper.createDocument();

Elementroot= dom.addElement("书架");

Elementbook1 = root.addElement("书").addAttribute("出版社", "中信出版社").addAttribute("编号", "110");

book1.addElement("作者").addText("郎咸平");

book1.addElement("书名").addText("货币战争");

book1.addElement("价格").addText("32.0元");

Elementbook2 = root.addElement("书").addAttribute("出版社", "人民出版社").addAttribute("编号", "111");

book2.addElement("作者").addText("柴静");

book2.addElement("书名").addText("遇见");

book2.addElement("价格").addText("38.0元");

//将输入格式设置gb2312编码格式

OutputFormatformat =OutputFormat.createPrettyPrint();

format.setEncoding("gb2312");

XMLWriterwriter = new XMLWriter(new FileWriter("book1.xml"),format);

writer.write(dom);

writer.close();

}

}