Java using xpath to parse xml example

XPath is XML Path Language, which is a language used to determine a certain part of the XML document. XPath is based on XML-like tree structure, providing the ability to find nodes in the data structure tree. At first, the original intention of XPath was to use it as a general syntax model between XPointer and XSL. But XPath was quickly adopted by developers as a small query language.

XPathTest.java

The code copy is as follows:

package com.hongyuan.test;

import java.io.File;

import java.io.IOException;

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 org.w3c.dom.Document;

import org.w3c.dom.Node;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

public class XPathTest {

public static void main(String[] args) throws ParserConfigurationException,

SAXException, IOException, XPathExpressionException {

// parse the file and generate the document object

DocumentBuilder builder = DocumentBuilderFactory.newInstance()

.newDocumentBuilder();

Document document = builder.parse(new File("bookstore.xml"));

// Generate XPath object

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

// Get the node value

String webTitle = (String) xpath.evaluate(

"/bookstore/book[@category='WEB']/title/text()", document,

XPathConstants.STRING);

System.out.println(webTitle);

System.out.println("============================================================= ===============================================================================================================================

// Get the node attribute value

String webTitleLang = (String) xpath.evaluate(

"/bookstore/book[@category='WEB']/title/@lang", document,

XPathConstants.STRING);

System.out.println(webTitleLang);

System.out.println("============================================================= ===============================================================================================================================

// Get the node object

Node bookWeb = (Node) xpath.evaluate(

"/bookstore/book[@category='WEB']", document,

XPathConstants.NODE);

System.out.println(bookWeb.getNodeName());

System.out.println("============================================================= ===============================================================================================================================

// Get the node collection

NodeList books = (NodeList) xpath.evaluate("/bookstore/book", document,

XPathConstants.NODESET);

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

Node book = books.item(i);

System.out.println(xpath.evaluate("@category", book,

XPathConstants.STRING));

}

System.out.println("============================================================= ===============================================================================================================================

}

}

bookstore.xml

The code copy is as follows:

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

<bookstore>

<book category="COOKING">

<title lang="en">Everyday Italian</title>

<author>Giada De Laurentiis</author>

<year>2005</year>

<price>30.00</price>

</book>

<book category="CHILDREN">

<title lang="en">Harry Potter</title>

<author>J K. Rowling</author>

<year>2005</year>

<price>29.99</price>

</book>

<book category="WEB">

<title lang="en">Learning XML</title>

<author>Erik T. Ray</author>

<year>2003</year>

<price>39.95</price>

</book>

</bookstore>

Running effect