详解Java解析XML的四种方法

li873582595

浏览: 114523 次
性别:

最近访客更多访客>>

q490085459

barrett9517

congyp0813

pmp4561705

博主相关

博客

微博

相册

留言

关于我

文章分类

社区版块

存档分类

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));   
	}   
}  
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;iElement 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();   
		}    
	}   
}

分享到：

Extjs中GridSummary实现EditorGridPanel ... | Java读取文件方法大全

2014-01-10 16:28
浏览 307
评论(0)
查看更多

发表评论

您还没有登录,请您登录后再发表评论

最近访客更多访客>>

博主相关

文章分类

社区版块

存档分类

最新评论