JAVA生成和解析XML的四种方法比较

by Xiang Zhuyuan

许海潮的专栏

XML现在已经成为一种通用的数据交换格式,它的平台无关性,语言无关性,系统无关性,给数据集成与交互带来了极大的方便。对于XML本身的语法知识与技术细节,需要阅读相关的技术文献,这里面包括的内容有DOM(Document

Object Model),DTD(Document Type Definition),SAX(Simple API for

XML),XSD(Xml Schema Definition),XSLT(Extensible Stylesheet Language

Transformations),具体可参阅w3c官方网站文档http://www.w3.org获取更多信息。

       

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;

public interface XmlDocument {

public void createXml(String fileName);

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;

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.TransformerConfigurationException;

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.dom.NodeList;

import org.xml.sax.SAXException;

public class DomDemo implements XmlDocument {

    private

Document document;

    private

String fileName;

    public

void init() {

      

try {

          

DocumentBuilderFactory factory = DocumentBuilderFactory

                 

.newInstance();

          

DocumentBuilder 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_x(“employees”);

      

this.document.appendChild(root);

      

Element employee = this.document.createElement_x(“employee”);

      

Element name = this.document.createElement_x(“name”);

      

name.appendChild(this.document.createTextNode(“丁宏亮“));

      

employee.appendChild(name);

      

Element sex = this.document.createElement_x(“sex”);

      

sex.appendChild(this.document.createTextNode(“m”));

      

employee.appendChild(sex);

      

Element age = this.document.createElement_x(“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);

          

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 (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(String fileName) {

      

try {

          

DocumentBuilderFactory dbf =

DocumentBuilderFactory.newInstance();

          

DocumentBuilder db = dbf.newDocumentBuilder();

          

Document document = db.parse(fileName);

          

NodeList employees = document.getChildNodes();

          

for (int i = 0; i

             

Node employee = employees.item(i);

             

NodeList employeeInfo = employee.getChildNodes();

             

for (int j = 0; j

                 

Node node = employeeInfo.item(j);

                 

NodeList employeeMeta = node.getChildNodes();

                 

for (int k = 0; k

                    

System.out.println(employeeMeta.item(k).getNodeName()

                           

+ “:” + employeeMeta.item(k).getTextdescription());

                 

}

             

}

          

}

          

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.getMessage());

      

}

    

}

}

  1. 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；

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.parsers.SAXParser;

import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;

import org.xml.sax.SAXException;

import org.xml.sax.helpers.DefaultHandler;

public class SaxDemo implements XmlDocument {

    public

void createXml(String fileName) {

       

System.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.printStackTrace();

      

} 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 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

             

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));

    }

}

  1. 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。

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.DocumentException;

import org.dom4j.DocumentHelper;

import org.dom4j.Element;

import org.dom4j.io.SAXReader;

import org.dom4j.io.XMLWriter;

public class Dom4jDemo implements XmlDocument {

    public

void createXml(String fileName) {

      

Document document = DocumentHelper.createDocument();

      

Element employees=document.addElement(“employees”);

      

Element employee=employees.addElement(“employee”);

      

Element name= employee.addElement(“name”);

      

name.setText(“ddvip”);

      

Element sex=employee.addElement(“sex”);

      

sex.setText(“m”);

      

Element age=employee.addElement(“age”);

      

age.setText(“29″);

      

try {

          

Writer fileWriter=new FileWriter(fileName);

          

XMLWriter xmlWriter=new XMLWriter(fileWriter);

          

xmlWriter.write(document);

          

xmlWriter.close();

      

} catch (IOException e) {

          

System.out.println(e.getMessage());

      

}

    }

    public

void parserXml(String fileName) {

       

File inputXml=new File(fileName);

       

SAXReader saxReader = new SAXReader();

       

try {

          

Document document = saxReader.read(inputXml);

          

Element employees=document.getRootElement();

          

for(Iterator i = employees.elementIterator(); i.hasNext();){

              

Element employee = (Element) i.next();

              

for(Iterator j = employee.elementIterator(); j.hasNext();){

                  

Element node=(Element) j.next();

                  

System.out.println(node.getName()+“:”+node.getText());

              

}

          

}

      

} catch (DocumentException e) {

          

System.out.println(e.getMessage());

      

}

    

System.out.println(“dom4j parserXml”);

    }

}

  1. JDOM生成和解析XML

           

    为减少DOM、SAX的编码量，出现了JDOM；优点：20-80原则，极大减少了代码量。使用场合：要实现的功能简单，如解析、创建等，但在底层，JDOM还是使用SAX（最常用）、DOM、Xanan文档。

package com.alisoft.facepay.framework.bean;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.util.List;

import org.jdom.Document;

import org.jdom.Element;

import org.jdom.JDOMException;

import org.jdom.input.SAXBuilder;

import org.jdom.output.XMLOutputter;

public class JDomDemo implements XmlDocument {

    public

void createXml(String fileName) {

     

Document document;

     

Element  root;

     

root=new Element(“employees”);

     

document=new Document(root);

     

Element employee=new Element(“employee”);

     

root.adddescription(employee);

     

Element name=new Element(“name”);

     

name.setText(“ddvip”);

     

employee.adddescription(name);

     

Element sex=new Element(“sex”);

     

sex.setText(“m”);

     

employee.adddescription(sex);

     

Element age=new Element(“age”);

     

age.setText(“23″);

     

employee.adddescription(age);

     

XMLOutputter XMLOut = new XMLOutputter();

     

try {

      

XMLOut.output(document, new FileOutputStream(fileName));

    } catch

(FileNotFoundException e) {

      

e.printStackTrace();

    } catch

(IOException e) {

      

e.printStackTrace();

    }

    }

    public

void parserXml(String fileName) {

      

SAXBuilder builder=new SAXBuilder(false);

      

try {

          

Document document=builder.build(fileName);

          

Element employees=document.getRootElement();

          

List employeeList=employees.getChildren(“employee”);

          

for(int i=0;i              

Element employee=(Element)employeeList.get(i);

             

List employeeInfo=employee.getChildren();

             

for(int j=0;j              

System.out.println(((Element)employeeInfo.get(j)).getName()+“:”+((Element)employeeInfo.get(j)).getValue());

             

}

          

}

      

} catch (JDOMException e) {

          

e.printStackTrace();

      

} catch (IOException e) {

          

e.printStackTrace();

      

}

    }

}

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/gundsoul/archive/2009/07/05/4322749.aspx