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(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();

       }

    }

}