JAVA 操作 XML 增删改查
package org.zyc.main;
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import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
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import org.w3c.dom.*;
import org.xml.sax.SAXException;
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import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.*;
import javax.xml.xpath.*;
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public class XMLModifier {
public static void main(String[] args) {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
Element theBook = null, theElem = null, root = null;
try {
factory.setIgnoringElementContentWhitespace(true);
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DocumentBuilder db = factory.newDocumentBuilder();
Document xmldoc = db.parse(new File("WebRoot/WEB-INF/classes/socket.xml"));
// Document xmldoc = db.parse(new File("src/socket.xml"));
root = xmldoc.getDocumentElement();
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// --- 新建一本书开始 ----
theBook = xmldoc.createElement("book");
theElem = xmldoc.createElement("name");
theElem.setTextContent("新书");
theBook.appendChild(theElem);
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theElem = xmldoc.createElement("price");
theElem.setTextContent("20");
theBook.appendChild(theElem);
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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 ----
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// --- 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。 ----
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// --- 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);
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// --- 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);
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saveXml("WebRoot/WEB-INF/classes/socket.xml", xmldoc);
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
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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");
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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();
}
}
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// 查找节点，并返回第一个符合条件节点
public static Node selectSingleNode(String express, Object source) {
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();
}
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return result;
}
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// 查找节点，返回符合条件的节点集。
public static NodeList selectNodes(String express, Object source) {
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();
}
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return result;
}
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// 将Document输出到文件
public static void saveXml(String fileName, Document doc) {
TransformerFactory transFactory = TransformerFactory.newInstance();
try {
Transformer transformer = transFactory.newTransformer();
transformer.setOutputProperty("indent", "yes");
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DOMSource source = new DOMSource();
source.setNode(doc);
StreamResult result = new StreamResult();
result.setOutputStream(new FileOutputStream(fileName));
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transformer.transform(source, result);
} catch (TransformerConfigurationException e) {
e.printStackTrace();
} catch (TransformerException e) {
e.printStackTrace();
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
}
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