Java解析XML的四種方法詳解

2019-11-26 16:19:01

字體：大中小

來源：轉載

供稿：網友

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了極大的方便。對于XML本身的語法知識與技術細節,需要閱讀相關的技術文獻,這里面包括的內容有DOM(Document Object Model),DTD(Document Type Definition),SAX(Simple API for XML),XSD(Xml Schema Definition),XSLT(Extensible Stylesheet Language Transformations),具體可參閱w3c官方網站文檔http://www.w3.org獲取更多信息。

XML在不同的語言里解析方式都是一樣的,只不過實現的語法不同而已?；镜慕馕龇绞接袃煞N,一種叫SAX，另一種叫DOM。SAX是基于事件流的解析,DOM是基于XML文檔樹結構的解析。假設我們XML的內容和結構如下:

復制代碼代碼如下:

 
<?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 它定義了XML文檔的建立與解析的接口。

復制代碼代碼如下:

 
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了一組接口。解析器讀入整個文檔，然后構建一個駐留內存的樹結構，然后代碼就可以使用 DOM 接口來操作這個樹結構。優點：整個文檔樹在內存中，便于操作；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：一旦解析了文檔還需多次訪問這些數據；硬件資源充足（內存、CPU）。

復制代碼代碼如下:

 
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，出現了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，適于Applet，下載。缺點：不是持久的；事件過后，若沒保存數據，那么數據就丟了；無狀態性；從事件中只能得到文本，但不知該文本屬于哪個元素；使用場合：Applet;只需XML文檔的少量內容，很少回頭訪問；機器內存少；
Java代碼

復制代碼代碼如下:

 
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("文檔開始打印了"); 
} 
public void endDocument() throws SAXException { 
System.out.println("文檔打印結束了"); 
} 
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("文檔開始打印了"); 
} 
public void endDocument() throws SAXException { 
System.out.println("文檔打印結束了"); 
} 
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

復制代碼代碼如下:

 
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，出現了JDOM；優點：20-80原則，極大減少了代碼量。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。

復制代碼代碼如下:

 
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;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(); 
} 
} 
} 