XML 的解析方法
四種XML解析方法:
(1)Dom生成和解析XML文檔
*解析器讀入整個文檔,然後構建一個駐留內存的樹結構,然後代碼就可以使用 DOM 接口來操作這個樹結構。
* 優點:整個文檔樹在內存中,便於操作;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)。
(2)SAX生成和解析XML文檔
* 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,適於Applet,下載。
* 缺點:不是持久的;事件過後,若沒保存數據,那麽數據就丟了;
* 無狀態性;從事件中只能得到文本,但不知該文本屬於哪個元素;
* 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;
(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。
(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。
首先編寫一個要解析的test.xml文件
Java代碼- <?xml version="1.0" encoding="UTF-8" standalone="no"?>
- <employees>
- <employee>
- <name>wxyfree</name>
- <age>30</age>
- </employee>
- <employee>
- <name>freewxy</name>
- <age>22</age>
- </employee>
- </employees>
然後,編寫一個XMLDocument接口
Java代碼- /**
- * 定義XML文檔建立與解析的接口
- * @author wxy
- *
- */
- public interface XMLDocument {
- /**
- *建立XML文檔
- * @param fileName 文件全路徑名
- */
- public void createXML(String fileName);
- /**
- * 解析XML文檔
- * @param fileName 文件全路徑名
- */
- public void parseXML(String fileName);
- }
一、
Java代碼- package review.testXML;
- import java.io.FileNotFoundException;
- import java.io.FileOutputStream;
- import java.io.IOException;
- 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;
- /**
- * 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,然後構建一個駐留內存的樹結構,然後代碼就可以使用 DOM 接口來操作這個樹結構。
- * 優點:整個文檔樹在內存中,便於操作;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)。
- * @param args
- */
- 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());
- }
- }
- @Override
- public void createXML(String fileName) {
- Element root=this.document.createElement("employees");//創建根元素
- this.document.appendChild(root);
- Element employee=this.document.createElement("employee");//創建子元素
- Element name=this.document.createElement("name");//添加元素的屬性
- name.appendChild(this.document.createTextNode("wxyfree"));
- employee.appendChild(name);//將元素添加到子元素中
- Element sex=this.document.createElement("sex");
- sex.appendChild(this.document.createTextNode("m"));
- Element age=this.document.createElement("age");
- age.appendChild(this.document.createTextNode("30"));
- employee.appendChild(age);
- root.appendChild(employee);//將子元素添加到根元素中
- TransformerFactory tf=TransformerFactory.newInstance();//此抽象類的實例能夠將源樹轉為結果樹
- try{
- Transformer transformer=tf.newTransformer();
- DOMSource source=new DOMSource(document);//創建帶有DOM節點的新輸入源
- transformer.setOutputProperty(OutputKeys.ENCODING,"UTF-8");//設置轉換中世紀的輸出屬性
- transformer.setOutputProperty(OutputKeys.INDENT, "yes");//
- PrintWriter pw=new PrintWriter(new FileOutputStream(fileName));
- StreamResult result=new StreamResult(pw);//充當轉換結果的持有者,可以為xml、純文本、HTML或某些其他格式的標記
- transformer.transform(source, result);//將XML Source轉換為Result
- System.out.println("生成XML文件成功");
- }catch(TransformerConfigurationException e){
- System.out.println(e.getMessage());
- } catch (TransformerException e) {
- System.out.println(e.getMessage());
- } catch (FileNotFoundException e) {
- System.out.println(e.getMessage());
- }
- }
- @Override
- public void parseXML(String fileName) {
- DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
- DocumentBuilder db;
- try {
- 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());
- }
- }
- }
- } catch (ParserConfigurationException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- } catch (SAXException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- } catch (IOException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- }
- System.out.println("解析完畢");
- }
- public static void main(String[] args){
- DomDemo d=new DomDemo();
- d.init();
- d.createXML("conf/test2.xml");
- d.parseXML("conf/test.xml");
- }
- }
二、
Java代碼- package review.testXML;
- 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.HandlerBase;
- import org.xml.sax.SAXException;
- import org.xml.sax.helpers.DefaultHandler;
- /**
- * 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,適於Applet,下載。
- * 缺點:不是持久的;事件過後,若沒保存數據,那麽數據就丟了;
- * 無狀態性;從事件中只能得到文本,但不知該文本屬於哪個元素;
- * 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;
- * @author wxy
- *
- */
- public class SaxDemo implements XMLDocument{
- @Override
- public void createXML(String fileName) {
- System.out.println("<<"+fileName+">>");
- }
- @Override
- public void parseXML(String fileName) {
- SAXParserFactory saxfac=SAXParserFactory.newInstance();
- try {
- SAXParser saxParser=saxfac.newSAXParser();
- InputStream ins=new FileInputStream(fileName);
- saxParser.parse(ins,new MySAXHandler());
- } catch (ParserConfigurationException e) {
- System.out.println(e.getMessage());
- } catch (SAXException e) {
- System.out.println(e.getMessage());
- } catch (FileNotFoundException e) {
- System.out.println(e.getMessage());
- } catch (IOException e) {
- System.out.println(e.getMessage());
- }
- }
- /**
- * @param args
- */
- public static void main(String[] args) {
- SaxDemo s=new SaxDemo();
- s.parseXML("conf/test.xml");
- }
- }
- class MySAXHandler extends DefaultHandler{
- boolean hasAttribute=false;
- Attributes attributes=null;
- /**
- * Receive notification of the beginning of the document.
- */
- public void startDocument()throws SAXException{
- System.out.print("文檔開始打印了");
- }
- /**
- * Receive notification of the end of the document.
- */
- public void endDocument()throws SAXException{
- System.out.print("文檔開始結束了");
- }
- /**
- * Receive notification of the start of an element.
- * @param uri The Namespace URI, or the empty string if the
- * element has no Namespace URI or if Namespace
- * processing is not being performed.
- * @param localName The local name (without prefix), or the
- * empty string if Namespace processing is not being
- * performed.
- * @param qName The qualified name (with prefix), or the
- * empty string if qualified names are not available.
- * @param attributes The attributes attached to the element. If
- * there are no attributes, it shall be an empty
- * Attributes object.
- * @exception org.xml.sax.SAXException Any SAX exception, possibly
- * wrapping another exception.
- */
- public void startElement(String uri,String localName,String qName,Attributes attributes)throws SAXException{
- if(qName.equals("employees")){return;}
- if(qName.equals("employee")){
- System.out.print(qName);
- }
- if(attributes.getLength()>0){
- this.attributes=attributes;
- this.hasAttribute=true;
- }
- }
- /**
- * Receive notification of the end of an element.
- * @param uri The Namespace URI, or the empty string if the
- * element has no Namespace URI or if Namespace
- * processing is not being performed.
- * @param localName The local name (without prefix), or the
- * empty string if Namespace processing is not being
- * performed.
- * @param qName The qualified name (with prefix), or the
- * empty string if qualified names are not available.
- * @exception org.xml.sax.SAXException Any SAX exception, possibly
- * wrapping another exception.
- */
- public void endElement(String uri,String localName,String qNaqme)throws SAXException{
- if(hasAttribute&&(attributes!=null)){
- for(int i=0;i<attributes.getLength();i++){
- System.out.print(attributes.getQName(0)+attributes.getValue(0));
- }
- }
- }
- /**
- * Receive notification of character data inside an element.
- * @param ch The characters.
- * @param start The start position in the character array.
- * @param length The number of characters to use from the
- * character array.
- */
- public void characters(char[] ch,int start,int length)throws SAXException{
- System.out.print(new String(ch,start,length));
- }
- }
三、
Java代碼- package review.testXML;
- 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;
- /**
- * Dom4j 生成XML文檔與解析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。
- * @author wxy
- *
- */
- public class Dom4jDemo implements XMLDocument{
- @Override
- public void createXML(String fileName) {
- Document document = DocumentHelper.createDocument();
- Element employees=document.addElement("employees");
- Element employee=document.addElement("employee");
- Element name=employee.addElement("name");
- name.setText("wxy");
- Element sex=employee.addElement("sex");
- name.setText("f");
- Element age=employee.addElement("age");
- name.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());
- }
- }
- @Override
- public void parseXML(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");
- }
- public static void main(String[] args) {
- Dom4jDemo d=new Dom4jDemo();
- d.parseXML("conf/test.xml");
- }
- }
四、
Java代碼- package review.testXML;
- 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;
- /**
- * 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。
- * @author wxy
- *
- */
- public class JDomDemo implements XMLDocument{
- @Override
- 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("wxywxy");
- employee.addContent(name);
- Element sex=new Element("sex");
- sex.setText("m");
- employee.addContent(sex);
- Element age=new Element("age");
- age.setText("25");
- employee.addContent(age);
- XMLOutputter XMLOut=new XMLOutputter();
- try {
- XMLOut.output(document, new FileOutputStream(fileName));
- } catch (FileNotFoundException e) {
- System.out.println(e.getMessage());
- } catch (IOException e) {
- System.out.println(e.getMessage());
- }
- }
- @Override
- public void parseXML(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)).getText());
- }
- }
- } catch (JDOMException e) {
- System.out.println(e.getMessage());
- } catch (IOException e) {
- System.out.println(e.getMessage());
- }
- }
- public static void main(String[] args){
- JDomDemo jd=new JDomDemo();
- jd.parseXML("conf/test.xml");
- }
- }
XML 的解析方法