Java解析XML四种方法

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(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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2 楼 xiangxuehai_jiaer 2011-09-09  

1 楼 caoxiaohui 2009-12-02