sax 和dom解析xml文件要点.docx

1、sax 和dom解析xml文件要点XML在不同的语言里解析方式都是一样的,只不过实现的语法不同而已。基本的解析方式有两种,一种叫SAX，另一种叫DOM。SAX是基于事件流的解析,DOM是基于XML文档树结构的解析。假设我们XML的内容和结构如下: ddviplinux m 30 本文使用JAVA语言来实现DOM与SAX的XML文档生成与解析。首先定义一个操作XML文档的接口XmlDocument 它定义了XML文档的建立与解析的接口。package com.alisoft.facepay.framework.bean; /* * * author hongliang.dinghl * 定义XM

2、L文档建立与解析的接口 */ public interface XmlDocument /* * 建立XML文档 * param fileName 文件全路径名称 */ public void createXml(String fileName); /* * 解析XML文档 * param fileName 文件全路径名称 */ public void parserXml(String fileName); 1.DOM生成和解析XML文档为 XML 文档的已解析版本定义了一组接口。解析器读入整个文档，然后构建一个驻留内存的树结构，然后代码就可以使用 DOM 接口来操作这个树结构。优点：整个文档

3、树在内存中，便于操作；支持删除、修改、重新排列等多种功能；缺点：将整个文档调入内存（包括无用的节点），浪费时间和空间；使用场合：一旦解析了文档还需多次访问这些数据；硬件资源充足（内存、CPU）。package com.alisoft.facepay.framework.bean; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream;

4、import java.io.PrintWriter; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.transform.OutputKeys; import javax.xml.transform.Transformer; import javax.xml.transform.TransformerConfigura

5、tionException; import javax.xml.transform.TransformerException; import javax.xml.transform.TransformerFactory; import javax.xml.transform.dom.DOMSource; import javax.xml.transform.stream.StreamResult; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.do

6、m.NodeList; import org.xml.sax.SAXException; /* * * author hongliang.dinghl * DOM生成与解析XML文档 */ public class DomDemo implements XmlDocument private Document document; private String fileName; public void init() try DocumentBuilderFactory factory = DocumentBuilderFactory .newInstance(); DocumentBuilde

7、r builder = factory.newDocumentBuilder(); this.document = builder.newDocument(); catch (ParserConfigurationException e) System.out.println(e.getMessage(); public void createXml(String fileName) Element root = this.document.createElement(employees); this.document.appendChild(root); Element employee =

8、 this.document.createElement(employee); Element name = this.document.createElement(name); name.appendChild(this.document.createTextNode(丁宏亮); employee.appendChild(name); Element sex = this.document.createElement(sex); sex.appendChild(this.document.createTextNode(m); employee.appendChild(sex); Elemen

9、t age = this.document.createElement(age); age.appendChild(this.document.createTextNode(30); employee.appendChild(age); root.appendChild(employee); TransformerFactory tf = TransformerFactory.newInstance(); try Transformer transformer = tf.newTransformer(); DOMSource source = new DOMSource(document);

10、transformer.setOutputProperty(OutputKeys.ENCODING, gb2312); transformer.setOutputProperty(OutputKeys.INDENT, yes); PrintWriter pw = new PrintWriter(new FileOutputStream(fileName); StreamResult result = new StreamResult(pw); transformer.transform(source, result); System.out.println(生成XML文件成功!); catch

11、 (TransformerConfigurationException e) System.out.println(e.getMessage(); catch (IllegalArgumentException e) System.out.println(e.getMessage(); catch (FileNotFoundException e) System.out.println(e.getMessage(); catch (TransformerException e) System.out.println(e.getMessage(); public void parserXml(S

12、tring fileName) try DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); DocumentBuilder db = dbf.newDocumentBuilder(); Document document = db.parse(fileName); NodeList employees = document.getChildNodes(); for (int i = 0; i employees.getLength(); i+) Node employee = employees.item(i);

13、 NodeList employeeInfo = employee.getChildNodes(); for (int j = 0; j employeeInfo.getLength(); j+) Node node = employeeInfo.item(j); NodeList employeeMeta = node.getChildNodes(); for (int k = 0; k employeeMeta.getLength(); k+) System.out.println(employeeMeta.item(k).getNodeName() + : + employeeMeta.

14、item(k).getTextContent(); System.out.println(解析完毕); catch (FileNotFoundException e) System.out.println(e.getMessage(); catch (ParserConfigurationException e) System.out.println(e.getMessage(); catch (SAXException e) System.out.println(e.getMessage(); catch (IOException e) System.out.println(e.getMes

15、sage(); 2.SAX生成和解析XML文档为解决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；Java代码package com.alisoft.facepay.framework.bean

16、;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.Attributes; import o

17、rg.xml.sax.SAXException; import org.xml.sax.helpers.DefaultHandler; /* * * author hongliang.dinghl * SAX文档解析 */ public class SaxDemo implements XmlDocument public void createXml(String fileName) System.out.println(); public void parserXml(String fileName) SAXParserFactory saxfac = SAXParserFactory.n

18、ewInstance(); 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.printStackT

19、race(); catch (IOException e) e.printStackTrace(); 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

20、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

21、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 SAXE

22、xception System.out.println(new String(ch, start, length); package com.alisoft.facepay.framework.bean; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import javax.xml.parsers.ParserConfigurationException; import javax.xml

23、.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; import org.xml.sax.Attributes; import org.xml.sax.SAXException; import org.xml.sax.helpers.DefaultHandler; /* * * author hongliang.dinghl * SAX文档解析 */ public class SaxDemo implements XmlDocument public void createXml(String fileName) Sys

24、tem.out.println(); 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.printS

25、tackTrace(); catch (SAXException e) e.printStackTrace(); catch (FileNotFoundException e) e.printStackTrace(); catch (IOException e) e.printStackTrace(); class MySAXHandler extends DefaultHandler boolean hasAttribute = false; Attributes attributes = null; public void startDocument() throws SAXExcepti

26、on 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

27、(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.ge

28、tQName(0) + attributes.getValue(0); public void characters(char ch, int start, int length) throws SAXException System.out.println(new String(ch, start, length); 3.DOM4J生成和解析XML文档DOM4J 是一个非常非常优秀的Java XML API，具有性能优异、功能强大和极端易用使用的特点，同时它也是一个开放源代码的软件。如今你可以看到越来越多的 Java 软件都在使用 DOM4J 来读写 XML，特别值得一提的是连 Sun 的 JAXM 也在用 DOM4J。Java代码package com.alisoft.facepay.framework.bean;import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.io.Writer; import java.util.Iterator; import org.dom4j.Document; import org.dom4j.Doc