JAVA解析XML的四種方法

shwenwen發表於2009-07-29
XML現在已經成為一種通用的資料交換格式,它的平臺無關性,語言無關性,系統無關性,給資料整合與互動帶來了極大的方便。[@more@]

XML現在已經成為一種通用的資料交換格式,它的平臺無關性,語言無關性,系統無關性,給資料整合與互動帶來了極大的方便。

XML現在已經成為一種通用的資料交換格式,它的平臺無關性,語言無關性,系統無關性,給資料整合與互動帶來了極大的方便。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,這裡麵包括的內容有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官方網站文件獲取更多資訊。
XML在不同的語言裡解析方式都是一樣的,只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文件樹結構的解析。假設我們XML的內容和結構如下:




ddviplinux
m
30

本文使用JAVA語言來實現DOM與SAX的XML文件生成與解析。
首先定義一個操作XML文件的介面XmlDocument 它定義了XML文件的建立與解析的介面。

package com.alisoft.facepay.framework.bean;
/**
*
* @author hongliang.dinghl
* 定義XML文件建立與解析的介面
*/
public interface XmlDocument {
/**
* 建立XML文件
* @param fileName 檔案全路徑名稱
*/
public void createXml(String fileName);
/**
* 解析XML文件
* @param fileName 檔案全路徑名稱
*/
public void parserXml(String fileName);
}


1.DOM生成和解析XML文件
為 XML 文件的已解析版本定義了一組介面。解析器讀入整個文件,然後構建一個駐留記憶體的樹結構,然後程式碼就可以使用 DOM 介面來操作這個樹結構。優點:整個文件樹在記憶體中,便於操作;支援刪除、修改、重新排列等多種功能;缺點:將整個文件調入記憶體(包括無用的節點),浪費時間和空間;使用場合:一旦解析了文件還需多次訪問這些資料;硬體資源充足(記憶體、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文件
*/
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檔案成功!");
} 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文件
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、文字、文件的開始或結束等時,傳送事件,程式設計師編寫響應這些事件的程式碼,儲存資料。優點:不用事先調入整個文件,佔用資源少;SAX解析器程式碼比DOM解析器程式碼小,適於Applet,下載。缺點:不是持久的;事件過後,若沒儲存資料,那麼資料就丟了;無狀態性;從事件中只能得到文字,但不知該文字屬於哪個元素;使用場合:Applet;只需XML文件的少量內容,很少回頭訪問;機器記憶體少;
Java程式碼
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文件解析
*/
public class SaxDemo implements XmlDocument {

public void createXml(String fileName) {
System.out.println("<>");
}

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("文件開始列印了");

}

public void endDocument() throws SAXException {

System.out.println("文件列印結束了");

}

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文件解析
*/
public class SaxDemo implements XmlDocument {

public void createXml(String fileName) {
System.out.println("<>");
}

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("文件開始列印了");

}

public void endDocument() throws SAXException {

System.out.println("文件列印結束了");

}

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));

}

}

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,極大減少了程式碼量。使用場合:要實現的功能簡單,如解析、建立等,但在底層,JDOM還是使用SAX(最常用)、DOM、Xanan文件。
Java程式碼

package testpro.thead;

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文件 * */
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();
}
}
}


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文件
*
*/
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();
}

}
}

原文地址:http://ddviplinux.javaeye.com/blog/357325

來自 “ ITPUB部落格 ” ,連結:http://blog.itpub.net/143526/viewspace-1024721/,如需轉載,請註明出處,否則將追究法律責任。

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