用dom4j对xml文档解析

package com.huowolf.dom4j;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
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文档的第二本书：<name>安徒生童话</name>
@Test
public void read() throws DocumentException {
SAXReader reader = new SAXReader();
Document document = reader.read(new File("books.xml"));

Element root = document.getRootElement();
Element book = (Element)root.elements("book").get(1);
//获取Text
String text= book.elementText("name");
System.out.println(text);
//获取value
String value = book.attributeValue("id");
System.out.println(value);

}

//在第一本书上添加一个国籍：<language>English</language>
@Test
public void add() throws DocumentException, IOException {
SAXReader reader = new SAXReader();
Document document = reader.read(new File("books.xml"));

Element book = document.getRootElement().element("book");
book.addElement("language").setText("English");

//输出文件
XMLWriter writer = new XMLWriter(new OutputStreamWriter(new FileOutputStream("books.xml"),"UTF-8"));
/*
* 格式化输出器可以指定码表
* OutputFormat format = OutputFormat.createPrettyPrint();
* format.setEncoding("gb2312");
* writer = new XMLWriter( System.out, format );
*/

writer.write( document );
writer.close();
}

//在第一本书的指定位置上添加一个新的售价：<price>95</price>
@Test
public void add2 ()throws Exception{
SAXReader reader = new SAXReader();
Document document = reader.read(new File("books.xml"));

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

List<Element> list = book.elements();

Element price = DocumentHelper.createElement("price");
price.setText("95");
list.add(3, price);

OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("UTF-8");

XMLWriter writer = new XMLWriter(new FileOutputStream("books.xml"), format);
writer.write(document);
writer.close();
}

//删除指定节点：<price>89</price>
@Test
public void delete() throws DocumentException, IOException {
SAXReader reader = new SAXReader();
Document document = reader.read(new File("books.xml"));

Element price = (Element) document.getRootElement().element("book").elements("price").get(1);
price.getParent().remove(price);

OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("UTF-8");

XMLWriter writer = new XMLWriter(new FileOutputStream("books.xml"), format);
writer.write(document);
writer.close();
}
}