詳解Java解析XML的四種方法 – JAVA編程語言程序開發技術文章

XML現在已經成為一種通用的數據交換格式,它的平臺無關性,語言無關性,系統無關性,給數據集成與交互帶來瞭極大的方便。對於XML本身的語法知識與技術細節,需要閱讀相關的技術文獻,這裡面包括的內容有DOM(Document Object Model),DTD(Document Type Definition),SAX(Simple API for XML),XSD(Xml Schema Definition),XSLT(Extensible Stylesheet Language Transformations),
XML在不同的語言裡解析方式都是一樣的,隻不過實現的語法不同而已。基本的解析方式有兩種,一種叫SAX,另一種叫DOM。SAX是基於事件流的解析,DOM是基於XML文檔樹結構的解析。假設我們XML的內容和結構如下:
<?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語言來實現DOM與SAX的XML文檔生成與解析。
首先定義一個操作XML文檔的接口XmlDocument 它定義瞭XML文檔的建立與解析的接口。

package com.alisoft.facepay.framework.bean;
/**
*
* @author hongliang.dinghl
* 定義XML文檔建立與解析的接口
*/
public interface XmlDocument {
/**
* 建立XML文檔
* @param fileName 文件全路徑名稱
*/
public void createXml(String fileName);
/**
* 解析XML文檔
* @param fileName 文件全路徑名稱
*/
public void parserXml(String fileName);
}
1.DOM生成和解析XML文檔

為 XML 文檔的已解析版本定義瞭一組接口。解析器讀入整個文檔,然後構建一個駐留內存的樹結構,然後代碼就可以使用 DOM 接口來操作這個樹結構。優點:整個文檔樹在內存中,便於操作;支持刪除、修改、重新排列等多種功能;缺點:將整個文檔調入內存(包括無用的節點),浪費時間和空間;使用場合:一旦解析瞭文檔還需多次訪問這些數據;硬件資源充足(內存、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生成與解析XML文檔
*/
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("解析完畢");
} 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文檔

為解決DOM的問題,出現瞭SAX。SAX ,事件驅動。當解析器發現元素開始、元素結束、文本、文檔的開始或結束等時,發送事件,程序員編寫響應這些事件的代碼,保存數據。優點:不用事先調入整個文檔,占用資源少;SAX解析器代碼比DOM解析器代碼小,適於Applet,下載。缺點:不是持久的;事件過後,若沒保存數據,那麼數據就丟瞭;無狀態性;從事件中隻能得到文本,但不知該文本屬於哪個元素;使用場合:Applet;隻需XML文檔的少量內容,很少回頭訪問;機器內存少;

Java代碼

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文檔解析 
*/ 
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("文檔開始打印瞭");  

}  

public void endDocument() throws SAXException {  

System.out.println("文檔打印結束瞭");  

}  

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文檔解析
*/
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("文檔開始打印瞭");
}
public void endDocument() throws SAXException {
System.out.println("文檔打印結束瞭");
}
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文檔

DOM4J 是一個非常非常優秀的Java XML API,具有性能優異、功能強大和極端易用使用的特點,同時它也是一個開放源代碼的軟件。如今你可以看到越來越多的 Java 軟件都在使用 DOM4J 來讀寫 XML,特別值得一提的是連 Sun 的 JAXM 也在用 DOM4J。

Java代碼

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文檔與解析XML文檔 
*/ 
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 

為減少DOM、SAX的編碼量,出現瞭JDOM;優點:20-80原則,極大減少瞭代碼量。使用場合:要實現的功能簡單,如解析、創建等,但在底層,JDOM還是使用SAX(最常用)、DOM、Xanan文檔。

  
[java]
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 生成與解析XML文檔  
*   
*/   
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();    
}     
 
}    
}    
  <p></p> 

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