JAVA操作XML的完整例子——W3C DOM篇
转自： http://blog.csdn.net/cds27/archive/2008/03/02/2139110.aspx
这是一个用JAVA W3C DOM 进行XML操作的例子，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 >
< 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 >
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)。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();
}
}
}
