Stax解析XML的简单实例

关键字解释：

Stax:Streaming API for XML（用于读写XML的流接口）

xml文件代码：

<?xml version="1.0"?>  <service>      <item>          <task>test</task>          <strategy>repeat</strategy>      </item>      <item>          <task>WebpageRespTask</task>          <strategy>single</strategy>      </item>  </service>  

Java代码：Junit4 testcase:TestStax

package unit_test;import java.io.InputStream;import javax.xml.stream.XMLEventReader;import javax.xml.stream.XMLInputFactory;import javax.xml.stream.XMLStreamConstants;import javax.xml.stream.XMLStreamException;import javax.xml.stream.XMLStreamReader;import javax.xml.stream.events.XMLEvent;import org.junit.Test;public class TestStax {//基于光标的解析方式@Testpublic void cursorBased() { XMLInputFactory factory = XMLInputFactory.newInstance();         InputStream is = null;         is = TestStax.class.getClassLoader().getResourceAsStream("service.xml");         XMLStreamReader  reader = null;         try {         reader = factory.createXMLStreamReader(is);while (reader.hasNext()) { int type = reader.next();// System.out.println(reader.next());// if (type==XMLStreamConstants.START_DOCUMENT||type==XMLStreamConstants.END_DOCUMENT) {// System.out.println(reader..toString());//}                 if(type==XMLStreamConstants.START_ELEMENT||type==XMLStreamConstants.END_ELEMENT){System.out.println(reader.getName().toString());}  else if(type==XMLStreamConstants.CHARACTERS) {    System.out.println(reader.getText().toString().trim());} }}          catch (XMLStreamException e) {e.printStackTrace();}            }//基于迭代的解析方式@Testpublic void iteratorBased(){ XMLInputFactory factory = XMLInputFactory.newInstance();         InputStream is = null;         is = TestStax.class.getClassLoader().getResourceAsStream("service.xml");         XMLEventReader  reader = null;         try {         reader = factory.createXMLEventReader(is);while (reader.hasNext()) {  XMLEvent event = reader.nextEvent();    if (event.isStartElement()) {String name = event.asStartElement().getName().toString();if (name.equals("strategy")) {System.out.println(reader.getElementText());}} }}          catch (XMLStreamException e) {e.printStackTrace();}      }

       //基于Xpath的形式，解析之前必须先加载整个Dom...DOM--->Document Object Model

        @Test       public void testXpath()        {          try {            System.out.println("-------------------------------textXpath----------------------------------------");               InputStream is = TestStax.class.getClassLoader().getSystemResourceAsStream("service.xml");                              DocumentBuilder db = DocumentBuilderFactory.newInstance().newDocumentBuilder();                    Document dom = db.parse(is);                    XPath xpath = XPathFactory.newInstance().newXPath();                    String xpStr = "//item[@id='task1']";                    NodeList list = (NodeList) xpath.evaluate(xpStr, dom, XPathConstants.NODESET);                    System.out.println(list.getLength());                    for (int index=0;index<list.getLength();index++) {                              Element ele = (Element) list.item(index);                          //System.out.println(ele.getNodeName()+"  :"+ele.getNodeValue());                             System.out.println(ele.getElementsByTagName("task").item(0).getTextContent());               }               System.out.println("-----------------------------------------------------------------------");     }       catch (SAXException e) {                         e.printStackTrace();                                } catch (IOException e) {                            // TODO Auto-generated catch block                                  e.printStackTrace();                                  }                             catch (ParserConfigurationException e) {                                e.printStackTrace();                           } catch (XPathExpressionException e) {                      // TODO Auto-generated catch block                                 e.printStackTrace();                           }     }<pre name="code" class="java">        <pre name="code" class="java">

//通过XMLStreamWriter对象来写入一个xml文档
@Testpublic void writeXml(){try {OutputStream os = new FileOutputStream("person.xml");XMLStreamWriter xmlSW = XMLOutputFactory.newInstance().createXMLStreamWriter(os);//XMLStreamWriter xmlSW = XMLOutputFactory.newInstance().createXMLStreamWriter(System.out); //写入xml文档的第一行xmlSW.writeStartDocument("GBK", "1.0"); xmlSW.writeEndDocument(); //写入xml节点 xmlSW.writeStartElement("person"); xmlSW.writeStartElement("perName"); xmlSW.writeCharacters("wuwh"); xmlSW.writeEndElement(); xmlSW.writeEndElement(); //在此方法之前，输出的内容都保存在cache中， //执行此方法会把存在缓存中数据实际输出。 xmlSW.flush(); xmlSW.close(); } catch (XMLStreamException e) {e.printStackTrace();} catch (FactoryConfigurationError e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();}}

    }