JAVA操作XML实例分析

本文实例讲述了JAVA操作XML的方法。分享给大家供大家参考。具体如下：

java代码如下：

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='哈里波特']", root);

            System.out.println("--- 查询找《哈里波特》 ----");

            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='哈里波特'], root)==================");

            //--- 新建一本书开始 ----

            theBook=xmldoc.createElement("book");

            theElem=xmldoc.createElement("name");

            theElem.setTextContent("新书");

            theBook.appendChild(theElem);

            theElem=xmldoc.createElement("price");

            theElem.setTextContent("20");

            theBook.appendChild(theElem);

            theElem=xmldoc.createElement("memo");

            theElem.setTextContent("新书的更好看。");

            theBook.appendChild(theElem);

            root.appendChild(theBook);

            System.out.println("--- 新建一本书开始 ----");

            output(xmldoc);

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

            //--- 新建一本书完成 ----

            //--- 下面对《哈里波特》做一些修改。 ----

            //--- 查询找《哈里波特》----

            //--- 此时修改这本书的价格 -----

            theBook.getElementsByTagName("price").item(0).setTextContent("15");//getElementsByTagName返回的是NodeList，所以要跟上item(0)。另外，getElementsByTagName("price")相当于xpath的".//price"。

            System.out.println("--- 此时修改这本书的价格 ----");

            output(theBook);

            //--- 另外还想加一个属性id，值为B01 ----

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

            System.out.println("--- 另外还想加一个属性id，值为B01 ----");

            output(theBook);

            //--- 对《哈里波特》修改完成。 ----

            //--- 要用id属性删除《三国演义》这本书 ----

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

            System.out.println("--- 要用id属性删除《三国演义》这本书 ----");

            output(theBook);

            theBook.getParentNode().removeChild(theBook);

            System.out.println("--- 删除后的ＸＭＬ ----");

            output(xmldoc);

            //--- 再将所有价格低于10的书删除 ----

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

            System.out.println("--- 再将所有价格低于10的书删除 ---");

            System.out.println("--- 符合条件的书有　"+someBooks.getLength()+"本。 ---");

            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) {//将node的XML字符串输出到控制台

        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) {//查找节点，并返回第一个符合条件节点

        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) {//查找节点，返回符合条件的节点集。

        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) {//将Document输出到文件

        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();

        }   

    }

}

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

<books>

<book>

<name>哈里波特</name>

<price>10</price>

<memo>这是一本很好看的书。</memo>

</book>

<book id="B02">

<name>三国演义</name>

<price>10</price>

<memo>四大名著之一。</memo>

</book>

<book id="B03">

<name>水浒</name>

<price>6</price>

<memo>四大名著之一。</memo>

</book>

<book id="B04">

<name>红楼</name>

<price>5</price>

<memo>四大名著之一。</memo>

</book>

</books>

希望本文所述对大家的java程序设计有所帮助。