JAVA解析XML的四种方法比较

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());

 

       }

 

     }

 

}

 

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;

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;

 

/**

 

 *

 

 * @author hongliang.dinghl

 

 * 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();

 

 

 

       }

 

 

 

    }

 

 

 

}

 

 

 

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(a

 

    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));

 

 

 

    }

 

 

 

}

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。

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;

 

/**

 

 *

 

 * @author hongliang.dinghl

 

 * Dom4j 生成XML文档与解析XML文档

 

 */

 

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”);

 

    }

 

 

 

 

 

}

 

 

4. 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;

 

/**

 

 *

 

 * @author hongliang.dinghl

 

 * JDOM 生成与解析XML文档

 

 *

 

 */

 

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.addContent(employee);

 

      Element name=new Element(“name”);

 

      name.setText(“ddvip”);

 

      employee.addContent(name);

 

      Element sex=new Element(“sex”);

 

      sex.setText(“m”);

 

      employee.addContent(sex);

 

      Element age=new Element(“age”);

 

      age.setText(“23″);

 

      employee.addContent(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<employeeList.size();i++){

 

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

 

              List employeeInfo=employee.getChildren();

 

              for(int j=0;j<employeeInfo.size();j++){

 

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

 

 

 

              }

 

           }

 

       } catch (JDOMException e) {

 

 

 

           e.printStackTrace();

 

       } catch (IOException e) {

 

 

 

           e.printStackTrace();

 

       }

 

 

 

    }

 

}

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