JAVA manipulation XML instance analysis

This article illustrates how JAVA can manipulate XML. Share with you for your reference. The details are as follows:

The Java code is as follows:

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import org.w3c.dom.*;

import org.xml.sax.SAXException;

import javax.xml.parsers.*;

import javax.xml.transform.*;

import javax.xml.transform.dom.DOMSource;

import javax.xml.transform.stream.*;

import javax.xml.xpath.*;

public class Test {

    public static void main(String[] args) {

        DocumentBuilderFactory factory=DocumentBuilderFactory.newInstance();

        Element theBook=null, theElem=null, root=null;

        try {

            factory.setIgnoringElementContentWhitespace(true);

            DocumentBuilder db=factory.newDocumentBuilder();

            Document xmldoc=db.parse(new File("Test1.xml"));

            root=xmldoc.getDocumentElement();

            theBook=(Element) selectSingleNode("/books/book[name=' Harry potter ']", root);

            System.out.println("---  Search for harry potter  ----");

            Element nameNode=(Element)theBook.getElementsByTagName("price").item(0); 

            String name=nameNode.getFirstChild().getNodeValue(); 

            System.out.println(name);

            output(theBook);

            System.out.println("=============selectSingleNode(books/book[name=' Harry potter '], root)==================");

            //-- new book to start --

            theBook=xmldoc.createElement("book");

            theElem=xmldoc.createElement("name");

            theElem.setTextContent(" A new book ");

            theBook.appendChild(theElem);

            theElem=xmldoc.createElement("price");

            theElem.setTextContent("20");

            theBook.appendChild(theElem);

            theElem=xmldoc.createElement("memo");

            theElem.setTextContent(" The new book is better. ");

            theBook.appendChild(theElem);

            root.appendChild(theBook);

            System.out.println("---  Start with a new book  ----");

            output(xmldoc);

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

            //-- new book completed --

            //-- make some changes to harry potter. - < br / >
            //-- looking for harry potter -- < br / >
            //-- now revise the price of this book --

            theBook.getElementsByTagName("price").item(0).setTextContent("15");//getElementsByTagName Returns the NodeList So keep up item(0) . In addition, getElementsByTagName("price") The equivalent of xpath the ".//price" . 

            System.out.println("---  Revise the price of this book at this time  ----");

            output(theBook);

            //-- we also want to add an attribute id of B01 --

            theBook.setAttribute("id", "B01");

            System.out.println("---  I also want to add a property id And has a value of B01 ----");

            output(theBook);

            //-- finishing the revision of harry potter. - < br / >
            //-- to use the id attribute to delete "romance of The Three Kingdoms" this book --

            theBook=(Element) selectSingleNode("/books/book[@id='B02']", root);

            System.out.println("---  Want to use id Property delete "romance of The Three Kingdoms" this book  ----");

            output(theBook);

            theBook.getParentNode().removeChild(theBook);

            System.out.println("---  The deleted XML  ----");

            output(xmldoc);

            //-- delete all books below the price of 10 --

            NodeList someBooks=selectNodes("/books/book[price<10]", root);

            System.out.println("---  And then lower all the prices 10 Book to delete  ---");

            System.out.println("---  Qualified books are available "+someBooks.getLength()+" Ben.  ---");

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

                someBooks.item(i).getParentNode().removeChild(someBooks.item(i));

            }

            output(xmldoc);

            saveXml("Test1_Edited.xml", xmldoc);

        } catch (ParserConfigurationException e) {

            e.printStackTrace();

        } catch (SAXException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

    public static void output(Node node) {//Output the XML string of the node to the console 

        TransformerFactory transFactory=TransformerFactory.newInstance();

        try {

            Transformer transformer = transFactory.newTransformer();

            transformer.setOutputProperty("encoding", "gb2312");

            transformer.setOutputProperty("indent", "yes");

            DOMSource source=new DOMSource();

            source.setNode(node);

            StreamResult result=new StreamResult();

            result.setOutputStream(System.out);

            transformer.transform(source, result);

        } catch (TransformerConfigurationException e) {

            e.printStackTrace();

        } catch (TransformerException e) {

            e.printStackTrace();

        }   

    }

    public static Node selectSingleNode(String express, Object source) {//Find the node and return the first qualified node 

        Node result=null;

        XPathFactory xpathFactory=XPathFactory.newInstance();

        XPath xpath=xpathFactory.newXPath();

        try {

            result=(Node) xpath.evaluate(express, source, XPathConstants.NODE);

        } catch (XPathExpressionException e) {

            e.printStackTrace();

        }

        return result;

    }

    public static NodeList selectNodes(String express, Object source) {//Find the node and return the set of nodes that meet the criteria. < br / >
        NodeList result=null;

        XPathFactory xpathFactory=XPathFactory.newInstance();

        XPath xpath=xpathFactory.newXPath();

        try {

            result=(NodeList) xpath.evaluate(express, source, XPathConstants.NODESET);

        } catch (XPathExpressionException e) {

            e.printStackTrace();

        }

        return result;

    }

    public static void saveXml(String fileName, Document doc) {//Output the Document to a file 

        TransformerFactory transFactory=TransformerFactory.newInstance();

        try {

            Transformer transformer = transFactory.newTransformer();

            transformer.setOutputProperty("indent", "yes");

            DOMSource source=new DOMSource();

            source.setNode(doc);

            StreamResult result=new StreamResult();

            result.setOutputStream(new FileOutputStream(fileName));

            transformer.transform(source, result);

        } catch (TransformerConfigurationException e) {

            e.printStackTrace();

        } catch (TransformerException e) {

            e.printStackTrace();

        } catch (FileNotFoundException e) {

            e.printStackTrace();

        }   

    }

}

 
The XML file is as follows:

<?xml version="1.0" encoding="GBK"?>

<books>

<book>

<name> Harry potter </name>

<price>10</price>

<memo> This is a very good book. </memo>

</book>

<book id="B02">

<name> The romance of The Three Kingdoms </name>

<price>10</price>

<memo> One of the four great classical novels. </memo>

</book>

<book id="B03">

<name> Water margin </name>

<price>6</price>

<memo> One of the four great classical novels. </memo>

</book>

<book id="B04">

<name> Red chamber </name>

<price>5</price>

<memo> One of the four great classical novels. </memo>

</book>

</books>

I hope this article has been helpful to your Java programming.