java解析xml四种方式(2)-SAX方式

来源：互联网发布：金山数据恢复和编辑：程序博客网时间：2024/06/05 11:25

java解析xml四种方式(2)-SAX方式

为解决DOM的问题，出现了SAX。SAX ，事件驱动。当解析器发现元素开始、元素结束、文本、文档的开始或结束等时，发送事件，程序员编写响应这些事件的代码，保存数据。

优点：不用事先调入整个文档，占用资源少；SAX解析器代码比DOM解析器代码小，适于Applet，下载。

缺点：不是持久的；事件过后，若没保存数据，那么数据就丢了；无状态性；从事件中只能得到文本，但不知该文本属于哪个元素；

使用场合：Applet;只需XML文档的少量内容，很少回头访问；机器内存少；

package com.michael.xml.sax;import org.xml.sax.Attributes;import org.xml.sax.SAXException;import org.xml.sax.helpers.DefaultHandler;/** * @author michael *  */public class MySAXHandler extends DefaultHandler {boolean hasAttribute = false;Attributes attributes = null;public void startDocument() throws SAXException {System.out.println("文档开始打印了");}public void endDocument() throws SAXException {System.out.println("文档打印结束了");}public void startElement(String uri, String localName, String qName,Attributes attributes) throws SAXException {if (qName.equals("employees")) {return;}if (qName.equals("employee")) {System.out.println(qName);}if (attributes.getLength() > 0) {this.attributes = attributes;this.hasAttribute = true;}}public void endElement(String uri, String localName, String qName)throws SAXException {if (hasAttribute && (attributes != null)) {for (int i = 0; i < attributes.getLength(); i++) {System.out.println(attributes.getQName(0)+ attributes.getValue(0));}}}public void characters(char[] ch, int start, int length)throws SAXException {System.out.println(new String(ch, start, length));}}

package com.michael.xml.sax;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.io.InputStream;import javax.xml.parsers.ParserConfigurationException;import javax.xml.parsers.SAXParser;import javax.xml.parsers.SAXParserFactory;import org.xml.sax.SAXException;import com.michael.xml.dom.XmlDocument;/** * @author michael SAX文档解析 */public class SaxDemo implements XmlDocument {public void createXml(String fileName) {System.out.println("----" + fileName + "---");}public void parserXml(String fileName) {SAXParserFactory saxfac = SAXParserFactory.newInstance();try {SAXParser saxparser = saxfac.newSAXParser();InputStream is = new FileInputStream(fileName);saxparser.parse(is, new MySAXHandler());} catch (ParserConfigurationException e) {e.printStackTrace();} catch (SAXException e) {e.printStackTrace();} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}public static void main(String[] args) {SaxDemo demo = new SaxDemo();// demo.createXml("d:/michael_sax.xml");demo.parserXml("d:/michael.xml");}}

0 0