JAVA操作XML的完整例子

JAVA操作XML的完整例子——W3C DOM篇

这是一个用JAVA W3C DOM 进行XML的的例子，包含了查询、增加、修改、删除、保存的基本操作。较完整的描述了一个XML的整个操作流程。适合刚入门JAVA XML操作的朋友参考和学习。

假设有XML文件：test1.xml

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

<books>

<book>

<memo>这是一本很好看的书。</memo>

</book>

<memo>四大名著之一。</memo>

</book>

<memo>四大名著之一。</memo>

</book>

<memo>四大名著之一。</memo>

</book>

</books>

下面是为Test.java

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();

//--- 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);

//--- 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》----

theBook=(Element) selectSingleNode("/books/book[name=''哈里波特'']", root);

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

output(theBook);

//--- 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)

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();

}

文章出处：http://www.diybl.com/course/3_program/java/javashl/200833/102631.html