java解析xml各种方法

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。

详解Java解析XML的四种方法:

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。

/** 
* @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）。 

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
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;

	// 获取xml的解析工厂
	public void init() {
		try {
			DocumentBuilderFactory factory = DocumentBuilderFactory
					.newInstance();
			DocumentBuilder builder = factory.newDocumentBuilder();
			this.document = builder.newDocument();
		} catch (Exception e) {
			// TODO: handle exception
			System.out.println(e.getMessage());
		}
	}

	// 创建
	@Override
	public void createXml(String filename) {
		// TODO Auto-generated method stub
		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, "utf-8");
			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());
		}
	}

	// 解析
	@Override
	public void parserXml(String filename) {
		// TODO Auto-generated method stub
		try {
			DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
			DocumentBuilder builder = dbf.newDocumentBuilder();
			Document document = builder.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 (ParserConfigurationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SAXException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}

}

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；

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 {
	@Override
	public void createXml(String filename) {
		// TODO Auto-generated method stub
		System.out.println("<<"+filename+">>");   
	}
	@Override
	public void parserXml(String filename) {
		// TODO Auto-generated method stub
		try {
			SAXParserFactory spf = SAXParserFactory.newInstance();
			SAXParser parser = spf.newSAXParser();
			InputStream is = new FileInputStream(filename);
			parser.parse(is,new MySAXHandler());
		} catch (ParserConfigurationException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (SAXException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (FileNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		
	}
}
class MySAXHandler extends DefaultHandler{
	boolean hasAttribute = false;
	Attributes attributes = null;
	@Override
	public void startDocument() throws SAXException {
		// TODO Auto-generated method stub
		super.startDocument();
		System.out.println("文档打印开始了"); 
	}
	@Override
	public void endDocument() throws SAXException {
		// TODO Auto-generated method stub
		super.endDocument();
		System.out.println("文档打印结束了"); 
	}
	
	@Override
	public void startElement(String arg0, String arg1, String arg2,
			Attributes arg3) throws SAXException {
		// TODO Auto-generated method stub
		if(arg2.equals("employees")){
			return;
		}
		if(arg2.equals("employee")){
			System.out.println(arg2);
		}
		
		if (arg3.getLength() > 0) {  
			this.attributes = arg3;  
			this.hasAttribute = true;  
		}  

	}
	@Override
	public void endElement(String arg0, String arg1, String arg2)
			throws SAXException {
		// TODO Auto-generated method stub
		if (hasAttribute && (attributes != null)) {  
			for (int i = 0; i < attributes.getLength(); i++) {  
			System.out.println(attributes.getQName(0)+ attributes.getValue(0));  
			}  
		}
	}
	@Override
	public void characters(char[] arg0, int arg1, int arg2) throws SAXException {
		// TODO Auto-generated method stub
		System.out.println(new String(arg0, arg1, arg2)); 
	}
}

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。

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。

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;jSystem.out.println(((Element)employeeInfo.get(j)).getName()+":"+((Element)employeeInfo.get(j)).getValue());   

}   
}   
} catch (JDOMException e) {   

e.printStackTrace();   
} catch (IOException e) {   

e.printStackTrace();   
}    

}   
}