Java解析XML的四種方法詳解

XML如今已經成爲一種通用的數據交換格式,平臺的無關性使得不少場合都須要用到XML。本文將詳細介紹用Java解析XML的四種方法 在作通常的XML數據交換過程當中，我更樂意傳遞XML字符串，而不是格式化的XML Document。這就涉及到XML字符串和Xml Document的轉換問題，說白了這是個很簡單的問題，本文就各類XML解析器分別列舉以下，以方便本身從此查閱。

=======================哈哈==================================== 1、使用最原始的javax.xml.parsers，標準的jdk api

// 字符串轉XML String xmlStr = "......"; StringReader sr = new StringReader(xmlStr); InputSource is = new InputSource(sr); DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder=factory.newDocumentBuilder(); Document doc = builder.parse(is);

//XML轉字符串 TransformerFactory tf = TransformerFactory.newInstance(); Transformer t = tf.newTransformer(); t.setOutputProperty("encoding","GB23121");//解決中文問題，試過用GBK不行 ByteArrayOutputStream bos = new ByteArrayOutputStream(); t.transform(new DOMSource(doc), new StreamResult(bos)); String xmlStr = bos.toString();

這裏的XML DOCUMENT爲org.w3c.dom.Document

2、使用dom4j後程序變得更簡單

// 字符串轉XML String xmlStr = "......"; Document document = DocumentHelper.parseText(xmlStr);

// XML轉字符串 Document document = ...; String text = document.asXML();

這裏的XML DOCUMENT爲org.dom4j.Document

3、使用JDOM

JDOM的處理方式和第一種方法處理很是相似

//字符串轉XML String xmlStr = "....."; StringReader sr = new StringReader(xmlStr); InputSource is = new InputSource(sr); Document doc = (new SAXBuilder()).build(is);

//XML轉字符串 Format format = Format.getPrettyFormat(); format.setEncoding("gb2312");//設置xml文件的字符爲gb2312，解決中文問題 XMLOutputter xmlout = new XMLOutputter(format); ByteArrayOutputStream bo = new ByteArrayOutputStream(); xmlout.output(doc,bo); String xmlStr = bo.toString();

這裏的XML DOCUMENT爲org.jdom.Document

4、JAVASCRIPT中的處理

//字符串轉XML var xmlStr = "....."; var xmlDoc = new ActiveXObject("Microsoft.XMLDOM"); xmlDoc.async=false; xmlDoc.loadXML(xmlStr); //能夠處理這個xmlDoc了 var name = xmlDoc.selectSingleNode("/person/name"); alert(name.text);

//XML轉字符串 var xmlDoc = ......; var xmlStr = xmlDoc.xml

這裏的XML DOCUMENT爲javascript版的XMLDOM

=============================我是黃金的分割線===========================

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。

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:

複製代碼代碼以下:

<?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。 首先定義一個操做XML文檔的接口XmlDocument 它定義了XML文檔的創建與解析的接口。

複製代碼代碼以下:

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

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）。 複製代碼代碼以下:

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

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； Java代碼

複製代碼代碼以下:

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。

Java代碼 複製代碼代碼以下:

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

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。 複製代碼代碼以下:

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(); } } }