JAVA操作XML的完整例子——W3C DOM篇
這是一個用JAVA W3C DOM 進行XML的的例子，包含了查詢、增加、修改、删除、儲存的基本操作。較完整的描述了一個XML的整個操作流程。适合剛入門JAVA XML操作的朋友參考和學習。
假設有XML檔案：test1.xml
<?xml version="1.0" encoding="UTF-8"?>
<books>
<book>
<name>哈裡波特</name>
<price>10</price>
<memo>這是一本很好看的書。</memo>
</book>
<book id="B02">
<name>三國演義</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>紅樓</name>
<price>5</price>
<memo>四大名著之一。</memo>
</book>
</books>
下面是為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();
//--- 建立一本書開始 ----
theBook=xmldoc.createElement("book");
theElem=xmldoc.createElement("name");
theElem.setTextContent("新書");
theBook.appendChild(theElem);
theElem=xmldoc.createElement("price");
theElem.setTextContent("20");
theBook.appendChild(theElem);
theElem=xmldoc.createElement("memo");
theElem.setTextContent("新書的更好看。");
theBook.appendChild(theElem);
root.appendChild(theBook);
System.out.println("--- 建立一本書開始 ----");
output(xmldoc);
//--- 建立一本書完成 ----
//--- 下面對《哈裡波特》做一些修改。 ----
//--- 查詢找《哈裡波特》----
theBook=(Element) selectSingleNode("/books/book[name=''哈裡波特'']", root);
System.out.println("--- 查詢找《哈裡波特》 ----");
output(theBook);
//--- 此時修改這本書的價格 -----
theBook.getElementsByTagName("price").item(0).setTextContent("15");//getElementsByTagName傳回的是NodeList，是以要跟上item(0)
System.out.println("--- 此時修改這本書的價格 ----");
output(theBook);
//--- 另外還想加一個屬性id，值為B01 ----
theBook.setAttribute("id", "B01");
System.out.println("--- 另外還想加一個屬性id，值為B01 ----");
output(theBook);
//--- 對《哈裡波特》修改完成。 ----
//--- 要用id屬性删除《三國演義》這本書 ----
theBook=(Element) selectSingleNode("/books/book[@id=''B02'']", root);
System.out.println("--- 要用id屬性删除《三國演義》這本書 ----");
output(theBook);
theBook.getParentNode().removeChild(theBook);
System.out.println("--- 删除後的ＸＭＬ ----");
output(xmldoc);
//--- 再将所有價格低于10的書删除 ----
NodeList someBooks=selectNodes("/books/book[price<10]", root);
System.out.println("--- 再将所有價格低于10的書删除 ---");
System.out.println("--- 符合條件的書有 "+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字元串輸出到控制台
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) ...{//查找節點，并傳回第一個符合條件節點
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) ...{//查找節點，傳回符合條件的節點集。
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輸出到檔案
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();
}
}
}
文章出處：http://www.diybl.com/course/3_program/java/javashl/200833/102631.html