JAVA解析XML的四种方法比较(1)

 转载自：http://www.alisdn.com/wordpress/?p=137

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:

<?xml version=”1.0″ encoding=”UTF-8″?> 

<employees>

  <employee>

    <name>ddviplinux</name>

    <sex>m</sex>

    <age>30</age>

  </employee>

</employees>

 

 

 

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XML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;

/**

 * 

 * @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();

           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(“employees”);

       this.document.appendChild(root);

       Element employee = 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);

       Element 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);

           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 < employees.getLength(); i++) {

              Node employee = employees.item(i);

              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.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.getMessage());

       }

 

    }

 

 

}