package XML.Class;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import javax.xml.xpath.XPath;

import javax.xml.xpath.XPathConstants;

import javax.xml.xpath.XPathExpressionException;

import javax.xml.xpath.XPathFactory;

import java.io.IOException;

/**

* @authtor liFei

* @date 2020/6/23-10:09

*/

public class XPathTest {

public static void main(String[] args) throws ParserConfigurationException, IOException, SAXException, XPathExpressionException {

//创建解析工厂

DocumentBuilderFactory documentBuilderFactory=DocumentBuilderFactory.newInstance();

//创建解析器

DocumentBuilder builder = documentBuilderFactory.newDocumentBuilder();

//通过解析器来读取配置文件,生成一个Document[org.w3c.dom]对象树

Document document = builder.parse("D:\\Practice\\JavaWeb\\src\\XML\\xml\\books.xml");

//创建Xpath对象

XPath xPath = XPathFactory.newInstance().newXPath();

/*

1.获取bookstore结点下book属性category值为web下的第二个title结点的文本内容

bookstore->book[@category="web"][2]->title

xpath路径：/bookstore/book[@category="web"][2]/title/text();

*/

String titleXpath="/bookstore/book[@category='web'][2]/title/text()";

String titleValue=(String)xPath.evaluate(titleXpath,document, XPathConstants.STRING);

System.out.println(titleValue);

/*

2.获取bookstore结点下book属性categoty值为web的title属性为en的结点内容

*/

String enXpath="/bookstore/book[@category='web']/title[@lang='en']/text()";

String enValue=(String)xPath.evaluate(enXpath,document,XPathConstants.STRING);

System.out.println(enValue);

/*

3.获取bookstore下book属性category值为cooking的title的lang属性的值

*/

String langXpath="/bookstore/book[@category='cooking']/title/@lang";

String langValue=(String)xPath.evaluate(langXpath,document,XPathConstants.STRING);

System.out.println(langValue);

/*

4.获取bookstore结点下所有book的结点集合

*/

NodeList bookList=(NodeList) xPath.evaluate("/bookstore/book",document,XPathConstants.NODESET);

for (int i = 0; i <bookList.getLength() ; i++) {

System.out.println("================");

Element bookElt=(Element)bookList.item(i);

String curTitle = (String) xPath.evaluate("title", bookElt, XPathConstants.STRING);

String authorValue=(String)xPath.evaluate("author",bookElt,XPathConstants.STRING);

String yearValue = (String) xPath.evaluate("year", bookElt, XPathConstants.STRING);

String priceValue=(String)xPath.evaluate("price",bookElt,XPathConstants.STRING);

System.out.println(curTitle);

System.out.println(authorValue);

System.out.println(yearValue);

System.out.println(priceValue);

}

}

}