XML如今已經成爲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。對於XML自己的語法知 識與技術細節,須要閱讀相關的技術文獻,這裏麪包括的內容有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。java
XML在不一樣的語言裏解析方式都是同樣的,只不過實現的語法不一樣而已。基本的解析方式有兩種,一種叫SAX,另外一種叫DOM。SAX是基於事件流的解析,DOM是基於XML文檔樹結構的解析。假設咱們XML的內容和結構以下:
node
<?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。
首先定義一個操做XML文檔的接口XmlDocument 它定義了XML文檔的創建與解析的接口。linux
package com.alisoft.facepay.framework.bean; /** * * @author hongliang.dinghl * 定義XML文檔創建與解析的接口 */ public interface XmlDocument { /** * 創建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文檔程序員
爲 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,而後構建一個駐留內存的樹結構,而後代碼就可使用 DOM 接口來操做這個樹結構。優勢:整個文檔樹在內存中,便於操做;支持刪除、修改、從新排列等多種功能;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屢次訪問這些數據;硬件資源充足(內存、CPU)。 app
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dom
爲解決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。優勢:不用事先調入整個 文檔,佔用資源少;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;事件事後,若沒保存數據,那麼數據就丟了;無狀態 性;從事件中只能獲得文本,但不知該文本屬於哪一個元素;使用場合:Applet;只需XML文檔的少許內容,不多回頭訪問;機器內存少;ide
Java代碼性能
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文檔網站
DOM4J 是一個很是很是優秀的Java XML API,具備性能優異、功能強大和極端易用使用的特色,同時它也是一個開放源代碼的軟件。現在你能夠看到愈來愈多的 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。ui
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
爲減小DOM、SAX的編碼量,出現了JDOM;優勢:20-80原則,極大減小了代碼量。使用場合:要實現的功能簡單,如解析、建立等,但在底層,JDOM仍是使用SAX(最經常使用)、DOM、Xanan文檔。
package com.alisoft.facepay.framework.bean; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException;