http://blog.csdn.net/smcwwh/article/details/7183869

關鍵字：Java解析xml、解析xml四種方法、DOM、SAX、JDOM、DOM4j、XPath

【引言】

目前在Java中用于解析XML的技術很多，主流的有DOM、SAX、JDOM、DOM4j，下文主要介紹這4種解析XML文檔技術的使用、優缺點及性能測試。

一、【基礎知識——掃盲】

sax、dom是兩種對xml文檔進行解析的方法(沒有具體實現，只是接口)，所以只有它們是無法解析xml文檔的；jaxp只是api，它進一步封裝了sax、dom兩種接口，并且提供了DomcumentBuilderFactory/DomcumentBuilder和SAXParserFactory/SAXParser（默認使用xerces解釋器）。

二、【DOM、SAX、JDOM、DOM4j簡單使用介紹】

1、【DOM(Document Object Model) 】
由W3C提供的接口，它將整個XML文檔讀入內存，構建一個DOM樹來對各個節點(Node)進行操作。
示例代碼：

[html] view plaincopyprint?

<?xml version="1.0" encoding="UTF-8"?> <university name="pku"><college name="c1"><class name="class1"><student name="stu1" sex='male' age="21" /><student name="stu2" sex='female' age="20" /><student name="stu3" sex='female' age="20" /></class><class name="class2"><student name="stu4" sex='male' age="19" /><student name="stu5" sex='female' age="20" /><student name="stu6" sex='female' age="21" /></class></college><college name="c2"><class name="class3"><student name="stu7" sex='male' age="20" /></class></college><college name="c3"></college> </university>

后文代碼中有使用到text.xml（該文檔放在src路徑下，既編譯后在classes路徑下），都是指該xml文檔。

[java] view plaincopyprint? package test.xml;import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream;import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; 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.w3c.dom.Text; import org.xml.sax.SAXException;/*** dom讀寫xml* @author whwang*/ public class TestDom {public static void main(String[] args) {read();//write();}public static void read() {DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();try {DocumentBuilder builder = dbf.newDocumentBuilder();InputStream in = TestDom.class.getClassLoader().getResourceAsStream("test.xml");Document doc = builder.parse(in);// root <university>Element root = doc.getDocumentElement();if (root == null) return;System.err.println(root.getAttribute("name"));// all college nodeNodeList collegeNodes = root.getChildNodes();if (collegeNodes == null) return;for(int i = 0; i < collegeNodes.getLength(); i++) {Node college = collegeNodes.item(i);if (college != null && college.getNodeType() == Node.ELEMENT_NODE) {System.err.println("\t" + college.getAttributes().getNamedItem("name").getNodeValue());// all class nodeNodeList classNodes = college.getChildNodes();if (classNodes == null) continue;for (int j = 0; j < classNodes.getLength(); j++) {Node clazz = classNodes.item(j);if (clazz != null && clazz.getNodeType() == Node.ELEMENT_NODE) {System.err.println("\t\t" + clazz.getAttributes().getNamedItem("name").getNodeValue());// all student nodeNodeList studentNodes = clazz.getChildNodes();if (studentNodes == null) continue;for (int k = 0; k < studentNodes.getLength(); k++) {Node student = studentNodes.item(k);if (student != null && student.getNodeType() == Node.ELEMENT_NODE) {System.err.print("\t\t\t" + student.getAttributes().getNamedItem("name").getNodeValue());System.err.print(" " + student.getAttributes().getNamedItem("sex").getNodeValue());System.err.println(" " + student.getAttributes().getNamedItem("age").getNodeValue());}}}}}}} catch (ParserConfigurationException e) {e.printStackTrace();} catch (FileNotFoundException e) {e.printStackTrace();} catch (SAXException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}public static void write() {DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();try {DocumentBuilder builder = dbf.newDocumentBuilder();InputStream in = TestDom.class.getClassLoader().getResourceAsStream("test.xml");Document doc = builder.parse(in);// root <university>Element root = doc.getDocumentElement();if (root == null) return;// 修改屬性root.setAttribute("name", "tsu");NodeList collegeNodes = root.getChildNodes();if (collegeNodes != null) {for (int i = 0; i <collegeNodes.getLength() - 1; i++) {// 刪除節點Node college = collegeNodes.item(i);if (college.getNodeType() == Node.ELEMENT_NODE) {String collegeName = college.getAttributes().getNamedItem("name").getNodeValue();if ("c1".equals(collegeName) || "c2".equals(collegeName)) {root.removeChild(college);} else if ("c3".equals(collegeName)) {Element newChild = doc.createElement("class");newChild.setAttribute("name", "c4");college.appendChild(newChild);}}}}// 新增節點Element addCollege = doc.createElement("college");addCollege.setAttribute("name", "c5");root.appendChild(addCollege);Text text = doc.createTextNode("text");addCollege.appendChild(text);// 將修改后的文檔保存到文件TransformerFactory transFactory = TransformerFactory.newInstance();Transformer transFormer = transFactory.newTransformer();DOMSource domSource = new DOMSource(doc);File file = new File("src/dom-modify.xml");if (file.exists()) {file.delete();}file.createNewFile();FileOutputStream out = new FileOutputStream(file); StreamResult xmlResult = new StreamResult(out);transFormer.transform(domSource, xmlResult);System.out.println(file.getAbsolutePath());} catch (ParserConfigurationException e) {e.printStackTrace();} catch (SAXException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} catch (TransformerConfigurationException e) {e.printStackTrace();} catch (TransformerException e) {e.printStackTrace();}} }

該代碼只要稍做修改，即可變得更加簡潔，無需一直寫if來判斷是否有子節點。

2、【SAX (Simple API for XML) 】
SAX不用將整個文檔加載到內存，基于事件驅動的API(Observer模式)，用戶只需要注冊自己感興趣的事件即可。SAX提供EntityResolver, DTDHandler, ContentHandler, ErrorHandler接口，分別用于監聽解析實體事件、DTD處理事件、正文處理事件和處理出錯事件，與AWT類似，SAX還提供了一個對這4個接口默認的類DefaultHandler（這里的默認實現，其實就是一個空方法），一般只要繼承DefaultHandler，重寫自己感興趣的事件即可。
示例代碼：

[java] view plaincopyprint? package test.xml;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.InputSource; import org.xml.sax.Locator; import org.xml.sax.SAXException; import org.xml.sax.SAXParseException; import org.xml.sax.helpers.DefaultHandler;/**** @author whwang*/ public class TestSAX {public static void main(String[] args) {read();write();}public static void read() {try {SAXParserFactory factory = SAXParserFactory.newInstance();SAXParser parser = factory.newSAXParser();InputStream in = TestSAX.class.getClassLoader().getResourceAsStream("test.xml");parser.parse(in, new MyHandler());} catch (ParserConfigurationException e) {e.printStackTrace();} catch (SAXException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}public static void write() {System.err.println("純SAX對于寫操作無能為力");}}// 重寫對自己感興趣的事件處理方法 class MyHandler extends DefaultHandler {@Overridepublic InputSource resolveEntity(String publicId, String systemId)throws IOException, SAXException {return super.resolveEntity(publicId, systemId);}@Overridepublic void notationDecl(String name, String publicId, String systemId)throws SAXException {super.notationDecl(name, publicId, systemId);}@Overridepublic void unparsedEntityDecl(String name, String publicId,String systemId, String notationName) throws SAXException {super.unparsedEntityDecl(name, publicId, systemId, notationName);}@Overridepublic void setDocumentLocator(Locator locator) {super.setDocumentLocator(locator);}@Overridepublic void startDocument() throws SAXException {System.err.println("開始解析文檔");}@Overridepublic void endDocument() throws SAXException {System.err.println("解析結束");}@Overridepublic void startPrefixMapping(String prefix, String uri)throws SAXException {super.startPrefixMapping(prefix, uri);}@Overridepublic void endPrefixMapping(String prefix) throws SAXException {super.endPrefixMapping(prefix);}@Overridepublic void startElement(String uri, String localName, String qName,Attributes attributes) throws SAXException {System.err.print("Element: " + qName + ", attr: ");print(attributes);}@Overridepublic void endElement(String uri, String localName, String qName)throws SAXException {super.endElement(uri, localName, qName);}@Overridepublic void characters(char[] ch, int start, int length)throws SAXException {super.characters(ch, start, length);}@Overridepublic void ignorableWhitespace(char[] ch, int start, int length)throws SAXException {super.ignorableWhitespace(ch, start, length);}@Overridepublic void processingInstruction(String target, String data)throws SAXException {super.processingInstruction(target, data);}@Overridepublic void skippedEntity(String name) throws SAXException {super.skippedEntity(name);}@Overridepublic void warning(SAXParseException e) throws SAXException {super.warning(e);}@Overridepublic void error(SAXParseException e) throws SAXException {super.error(e);}@Overridepublic void fatalError(SAXParseException e) throws SAXException {super.fatalError(e);}private void print(Attributes attrs) {if (attrs == null) return;System.err.print("[");for (int i = 0; i < attrs.getLength(); i++) {System.err.print(attrs.getQName(i) + " = " + attrs.getValue(i));if (i != attrs.getLength() - 1) {System.err.print(", ");}}System.err.println("]");} }

3、【JDOM】
JDOM與DOM非常類似，它是處理XML的純JAVA API，API大量使用了Collections類，且JDOM僅使用具體類而不使用接口。　JDOM 它自身不包含解析器。它通常使用 SAX2 解析器來解析和驗證輸入 XML 文檔（盡管它還可以將以前構造的 DOM 表示作為輸入）。它包含一些轉換器以將 JDOM 表示輸出成 SAX2 事件流、DOM 模型或 XML 文本文檔
示例代碼：

[java] view plaincopyprint? package test.xml;import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.util.List;import org.jdom.Attribute; import org.jdom.Document; import org.jdom.Element; import org.jdom.JDOMException; import org.jdom.input.SAXBuilder; import org.jdom.output.XMLOutputter;/*** JDom讀寫xml* @author whwang*/ public class TestJDom {public static void main(String[] args) {//read();write();}public static void read() {try {boolean validate = false;SAXBuilder builder = new SAXBuilder(validate);InputStream in = TestJDom.class.getClassLoader().getResourceAsStream("test.xml");Document doc = builder.build(in);// 獲取根節點 <university>Element root = doc.getRootElement();readNode(root, "");} catch (JDOMException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}@SuppressWarnings("unchecked")public static void readNode(Element root, String prefix) {if (root == null) return;// 獲取屬性List<Attribute> attrs = root.getAttributes();if (attrs != null && attrs.size() > 0) {System.err.print(prefix);for (Attribute attr : attrs) {System.err.print(attr.getValue() + " ");}System.err.println();}// 獲取他的子節點List<Element> childNodes = root.getChildren();prefix += "\t";for (Element e : childNodes) {readNode(e, prefix);}}public static void write() {boolean validate = false;try {SAXBuilder builder = new SAXBuilder(validate);InputStream in = TestJDom.class.getClassLoader().getResourceAsStream("test.xml");Document doc = builder.build(in);// 獲取根節點 <university>Element root = doc.getRootElement();// 修改屬性root.setAttribute("name", "tsu");// 刪除boolean isRemoved = root.removeChildren("college");System.err.println(isRemoved);// 新增Element newCollege = new Element("college");newCollege.setAttribute("name", "new_college");Element newClass = new Element("class");newClass.setAttribute("name", "ccccc");newCollege.addContent(newClass);root.addContent(newCollege);XMLOutputter out = new XMLOutputter();File file = new File("src/jdom-modify.xml");if (file.exists()) {file.delete();}file.createNewFile();FileOutputStream fos = new FileOutputStream(file);out.output(doc, fos);} catch (JDOMException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}}

4、【DOM4j】
dom4j是目前在xml解析方面是最優秀的(Hibernate、Sun的JAXM也都使用dom4j來解析XML)，它合并了許多超出基本 XML 文檔表示的功能，包括集成的 XPath 支持、XML Schema 支持以及用于大文檔或流化文檔的基于事件的處理
示例代碼：

[java] view plaincopyprint? package test.xml;import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.io.InputStream; import java.util.List;import org.dom4j.Attribute; import org.dom4j.Document; import org.dom4j.DocumentException; import org.dom4j.DocumentHelper; import org.dom4j.Element; import org.dom4j.ProcessingInstruction; import org.dom4j.VisitorSupport; import org.dom4j.io.SAXReader; import org.dom4j.io.XMLWriter;/*** Dom4j讀寫xml* @author whwang*/ public class TestDom4j {public static void main(String[] args) {read1();//read2();//write();}public static void read1() {try {SAXReader reader = new SAXReader();InputStream in = TestDom4j.class.getClassLoader().getResourceAsStream("test.xml");Document doc = reader.read(in);Element root = doc.getRootElement();readNode(root, "");} catch (DocumentException e) {e.printStackTrace();}}@SuppressWarnings("unchecked")public static void readNode(Element root, String prefix) {if (root == null) return;// 獲取屬性List<Attribute> attrs = root.attributes();if (attrs != null && attrs.size() > 0) {System.err.print(prefix);for (Attribute attr : attrs) {System.err.print(attr.getValue() + " ");}System.err.println();}// 獲取他的子節點List<Element> childNodes = root.elements();prefix += "\t";for (Element e : childNodes) {readNode(e, prefix);}}public static void read2() {try {SAXReader reader = new SAXReader();InputStream in = TestDom4j.class.getClassLoader().getResourceAsStream("test.xml");Document doc = reader.read(in);doc.accept(new MyVistor());} catch (DocumentException e) {e.printStackTrace();}}public static void write() {try {// 創建一個xml文檔Document doc = DocumentHelper.createDocument();Element university = doc.addElement("university");university.addAttribute("name", "tsu");// 注釋university.addComment("這個是根節點");Element college = university.addElement("college");college.addAttribute("name", "cccccc");college.setText("text");File file = new File("src/dom4j-modify.xml");if (file.exists()) {file.delete();}file.createNewFile();XMLWriter out = new XMLWriter(new FileWriter(file));out.write(doc);out.flush();out.close();} catch (IOException e) {e.printStackTrace();}} }class MyVistor extends VisitorSupport {public void visit(Attribute node) {System.out.println("Attibute: " + node.getName() + "="+ node.getValue());}public void visit(Element node) {if (node.isTextOnly()) {System.out.println("Element: " + node.getName() + "="+ node.getText());} else {System.out.println(node.getName());}}@Overridepublic void visit(ProcessingInstruction node) {System.out.println("PI:" + node.getTarget() + " " + node.getText());} }

三、【性能測試】

環境：AMD4400+ 2.0+GHz主頻 JDK6.0
運行參數：-Xms400m -Xmx400m
xml文件大小：10.7M
結果：
DOM: >581297ms
SAX: 8829ms
JDOM: 581297ms
DOM4j: 5309ms
時間包括IO的，只是進行了簡單的測試，僅供參考！！！！

四、【對比】

1、【DOM】
DOM是基于樹的結構，通常需要加載整文檔和構造DOM樹，然后才能開始工作。
優點：
?? ?a、由于整棵樹在內存中，因此可以對xml文檔隨機訪問
?? ?b、可以對xml文檔進行修改操作
?? ?c、較sax，dom使用也更簡單。
缺點：
?? ?a、整個文檔必須一次性解析完
?? ?a、由于整個文檔都需要載入內存，對于大文檔成本高
2、【SAX】
SAX類似流媒體，它基于事件驅動的，因此無需將整個文檔載入內存，使用者只需要監聽自己感興趣的事件即可。
優點：
?? ?a、無需將整個xml文檔載入內存，因此消耗內存少
?? ?b、可以注冊多個ContentHandler
缺點：
?? ?a、不能隨機的訪問xml中的節點
?? ?b、不能修改文檔
3、【JDOM】
JDOM是純Java的處理XML的API，其API中大量使用Collections類，
優點：
?? ?a、DOM方式的優點
?? ?b、具有SAX的Java規則
缺點
?? ?a、DOM方式的缺點
4、【DOM4J】
這4中xml解析方式中，最優秀的一個，集易用和性能于一身。

五、【小插曲XPath】

XPath 是一門在 XML 文檔中查找信息的語言， 可用來在 XML 文檔中對元素和屬性進行遍歷。XPath 是 W3C XSLT 標準的主要元素，并且 XQuery 和 XPointer 同時被構建于 XPath 表達之上。因此，對 XPath 的理解是很多高級 XML 應用的基礎。
XPath非常類似對數據庫操作的SQL語言，或者說JQuery，它可以方便開發者抓起文檔中需要的東西。（dom4j也支持xpath）
示例代碼：

[java] view plaincopyprint? package test.xml;import java.io.IOException; import java.io.InputStream;import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.xpath.XPath; import javax.xml.xpath.XPathConstants; import javax.xml.xpath.XPathExpression; import javax.xml.xpath.XPathExpressionException; import javax.xml.xpath.XPathFactory;import org.w3c.dom.Document; import org.w3c.dom.NodeList; import org.xml.sax.SAXException;public class TestXPath {public static void main(String[] args) {read();}public static void read() {try {DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();DocumentBuilder builder = dbf.newDocumentBuilder();InputStream in = TestXPath.class.getClassLoader().getResourceAsStream("test.xml");Document doc = builder.parse(in);XPathFactory factory = XPathFactory.newInstance();XPath xpath = factory.newXPath();// 選取所有class元素的name屬性// XPath語法介紹： http://w3school.com.cn/xpath/XPathExpression expr = xpath.compile("//class/@name");NodeList nodes = (NodeList) expr.evaluate(doc, XPathConstants.NODESET);for (int i = 0; i < nodes.getLength(); i++) {System.out.println("name = " + nodes.item(i).getNodeValue());}} catch (XPathExpressionException e) {e.printStackTrace();} catch (ParserConfigurationException e) {e.printStackTrace();} catch (SAXException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}}

六、【補充】

注意4種解析方法對TextNode（文本節點）的處理：

1、在使用DOM時，調用node.getChildNodes()獲取該節點的子節點，文本節點也會被當作一個Node來返回，如：

[html] view plaincopyprint? <?xml version="1.0" encoding="UTF-8"?> <university name="pku"><college name="c1"><class name="class1"><student name="stu1" sex='male' age="21" /><student name="stu2" sex='female' age="20" /><student name="stu3" sex='female' age="20" /></class></college> </university> [java] view plaincopyprint? package test.xml;import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStream; import java.util.Arrays;import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException;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;/*** dom讀寫xml* @author whwang*/ public class TestDom2 {public static void main(String[] args) {read();}public static void read() {DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();try {DocumentBuilder builder = dbf.newDocumentBuilder();InputStream in = TestDom2.class.getClassLoader().getResourceAsStream("test.xml");Document doc = builder.parse(in);// root <university>Element root = doc.getDocumentElement();if (root == null) return; // System.err.println(root.getAttribute("name"));// all college nodeNodeList collegeNodes = root.getChildNodes();if (collegeNodes == null) return;System.err.println("university子節點數：" + collegeNodes.getLength());System.err.println("子節點如下：");for(int i = 0; i < collegeNodes.getLength(); i++) {Node college = collegeNodes.item(i);if (college == null) continue;if (college.getNodeType() == Node.ELEMENT_NODE) {System.err.println("\t元素節點：" + college.getNodeName());} else if (college.getNodeType() == Node.TEXT_NODE) {System.err.println("\t文本節點：" + Arrays.toString(college.getTextContent().getBytes()));}}} catch (ParserConfigurationException e) {e.printStackTrace();} catch (FileNotFoundException e) {e.printStackTrace();} catch (SAXException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}} }

輸出的結果是：

[java] view plaincopyprint? university子節點數：3 子節點如下：文本節點：[10, 9]元素節點：college文本節點：[10]

其中\n的ASCII碼為10，\t的ASCII碼為9。結果讓人大吃一驚，university的子節點數不是1，也不是2，而是3，這3個子節點都是誰呢？為了看得更清楚點，把xml文檔改為：

[html] view plaincopyprint? <?xml version="1.0" encoding="UTF-8"?> <university name="pku">11<college name="c1"><class name="class1"><student name="stu1" sex='male' age="21" /><student name="stu2" sex='female' age="20" /><student name="stu3" sex='female' age="20" /></class></college>22 </university>

還是上面的程序，輸出結果為：

[java] view plaincopyprint? university子節點數：3 子節點如下：文本節點：[49, 49, 10, 9]元素節點：college文本節點：[50, 50, 10]

其中數字1的ASCII碼為49，數字2的ASCII碼為50。

2、使用SAX來解析同DOM，當你重寫它的public void characters(char[] ch, int start, int length)方法時，你就能看到。

3、JDOM，調用node.getChildren()只返回子節點，不包括TextNode節點（不管該節點是否有Text信息）。如果要獲取該節點的Text信息，可以調用node.getText()方法，該方法返回節點的Text信息，也包括\n\t等特殊字符。

4、DOM4j同JDOM

參考：

http://www.docin.com/p-78963650.html

http://wenku.baidu.com/view/b091f9360b4c2e3f5727638b.html

http://kree.iteye.com/blog/668280

?

?

?

詳解Java解析XML的四種方法

http://developer.51cto.com/art/200903/117512.htm

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。基本的解析方式有兩種,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:?

<?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。

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）。?

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

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

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。

?? 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();?? }??? }?? }??

【編輯推薦】

XML新手入門 創建構造良好的XML

實現XML和Web服務時要避免的三種常見錯誤

數據庫中的pureXML優點介紹

?

總結

以上是生活随笔為你收集整理的Java解析XML汇总（DOM/SAX/JDOM/DOM4j/XPath）的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。