dom4j解析

package cn.itcast.dom4j;


import java.io.File;
import java.io.FileOutputStream;
import java.util.List;
import org.dom4j.Document;
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文档数据：<书名>Java就业培训教程</书名>
@Test
public void read() throws Exception{

SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/book1.xml"));

Element root = document.getRootElement();
Element bookname = root.element("书").element("书名");
System.out.println(bookname.getText());
}

//<书 name="yyyyyyy">
@Test
public void readAttr() throws Exception{

SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/book1.xml"));

Element root = document.getRootElement();
String value = root.element("书").attributeValue("name");
System.out.println(value);
}

//向xml文档中添加<售价>19元</售价>
@Test
public void add() throws Exception{
SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/book1.xml"));

Element price = DocumentHelper.createElement("售价");
price.setText("19元");

document.getRootElement().element("书").add(price);

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

XMLWriter writer = new XMLWriter(new FileOutputStream("src/book1.xml"),format);
writer.write(document);  //utf-8
writer.close();
}

//修改：<售价>109</售价>  为209
@Test
public void update() throws Exception{
SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/book1.xml"));

Element price = (Element) document.getRootElement().element("书").elements("售价").get(1);
price.setText("209元");

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

XMLWriter writer = new XMLWriter(new FileOutputStream("src/book1.xml"),format);
writer.write(document);  //utf-8
writer.close();

}
//删除：<售价>109</售价>
@Test
public void delete() throws Exception{
SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/book1.xml"));

Element price = (Element) document.getRootElement().element("书").elements("售价").get(0);
price.getParent().remove(price);

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

XMLWriter writer = new XMLWriter(new FileOutputStream("src/book1.xml"),format);
writer.write(document);  //utf-8
writer.close();
}



//向指定位置增加售价结点
@Test
public void add2() throws Exception{
SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/book1.xml"));

Element price = DocumentHelper.createElement("售价");
price.setText("19元");

List list = document.getRootElement().element("书").elements();
list.add(1, price);


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

XMLWriter writer = new XMLWriter(new FileOutputStream("src/book1.xml"),format);
writer.write(document);  //utf-8
writer.close();

}

@Test
public void findWithXpath() throws Exception{
SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/book1.xml"));

Element e = (Element) document.selectNodes("//书名").get(1);
System.out.println(e.getText());
}

@Test
public void findUser() throws Exception{
String username = "aaa";
String password = "1233";

SAXReader reader = new SAXReader();
Document document = reader.read(new File("src/users.xml"));

Element e = (Element) document.selectSingleNode("//user[@username='"+username+"' and @password='"+password+"']");
if(e!=null){
System.out.println("让用户登陆成功！！");
}else{
System.out.println("用户名和密码不正确！！");
}

}

}

<?xml version="1.0" encoding="UTF-8"?>


<书架> 
  <书 name="yyyyyyy"> 
    <售价>19元</售价>  
    <售价>19元</售价>
    <书名>Java就业培训教程</书名>  
    <作者>张孝祥</作者>  
    <售价>209元</售价>  
    <售价>19元</售价>  
    <售价>19元</售价> 
  </书>  
  <书> 
    <书名>JavaScript网页开发</书名>  
    <作者>张孝祥</作者>  
    <售价>28.00元</售价> 
  </书> 
</书架>