使用Stax处理XML
java提供的XML处理
Stax处理XML：不会把XML一次性读入
基于光标的查找（使用reader一个一个读）
基于迭代模型的查找
过滤器的使用
XPATH的使用
使用XMLStreamWriter创建xml
使用Transformer更新节点信息
<?xml version="1.0" encoding="UTF-8"?><bookstore><book category="COOKING"><title lang="en">Everyday Italian</title><author>Giada De Laurentiis</author><year>2005</year><price>30.00</price></book><book category="CHILDREN"><title lang="en">Harry Potter</title><author>J K. Rowling</author><year>2005</year><price>29.99</price></book><book category="WEB"><title lang="en">XQuery Kick Start</title><author>James McGovern</author><author>Per Bothner</author><author>Kurt Cagle</author><author>James Linn</author><author>Vaidyanathan Nagarajan</author><year>2003</year><price>49.99</price></book><book category="WEB"><title lang="en">Learning XML</title><author>Erik T. Ray</author><year>2003</year><price>39.95</price></book></bookstore>
package com.hqh.stax;import static org.junit.Assert.*;import java.io.IOException;import java.io.InputStream;import javax.xml.stream.XMLInputFactory;import javax.xml.stream.XMLStreamConstants;import javax.xml.stream.XMLStreamException;import javax.xml.stream.XMLStreamReader;import org.junit.Test;public class TestStax {/** * Stax将XML从结构上划分成了若干块 * 在XMLStreamConstants中定义了若干常量来表示 * 文档起始：START_DOCUMENT=7 * 文档结束：END_DOCUMENT=8 * 元素开始标签：START_ELEMENT=1 * 元素结束标签：END_ELEMENT=2 * 元素节点中的内容：CHARACTERS=4 * 空格：SPACE=6 * ... * */@Testpublic void testStax01() {XMLInputFactory factory = XMLInputFactory.newInstance();InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream("books.xml");try {XMLStreamReader reader = factory.createXMLStreamReader(is);while(reader.hasNext()) {//获取下一个节点int type = reader.next();if(type==XMLStreamConstants.START_ELEMENT) {//开始元素String name = reader.getName().toString();//根据name决定是否操纵该节点中的信息System.out.println(name);if(name.equals("book")) {//输出book定义的属性System.out.println(reader.getAttributeName(0)+":"+reader.getAttributeValue(0));}} else if(type==XMLStreamConstants.CHARACTERS) {//元素中的内容System.out.println("\t"+reader.getText().trim());} else if(type==XMLStreamConstants.END_ELEMENT) {//结束元素System.out.println("/"+reader.getName());}}} catch (XMLStreamException e) {e.printStackTrace();} finally {if(is!=null)try {is.close();} catch (IOException e) {e.printStackTrace();}}}/** * 灵活的对xml中关注的节点进行操作 */@Testpublic void testStax02() {XMLInputFactory factory = XMLInputFactory.newInstance();InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream("books.xml");try {XMLStreamReader reader = factory.createXMLStreamReader(is);while(reader.hasNext()) {//获取下一个节点int type = reader.next();//输出每本书的价格if(type==XMLStreamConstants.START_ELEMENT) {String name = reader.getName().toString();//根据name决定是否操纵该节点中的信息if(name.equals("title")) {//输出book定义的属性System.out.print(reader.getElementText().trim()+":");} else if(name.equals("price")) {System.out.println(reader.getElementText().trim());}}}} catch (XMLStreamException e) {e.printStackTrace();} finally {if(is!=null)try {is.close();} catch (IOException e) {e.printStackTrace();}}}}/** * 基于迭代的方式XMLEventReader */@Testpublic void testStax03() {XMLInputFactory factory = XMLInputFactory.newInstance();InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream("books.xml");XMLEventReader reader = null;try {//创建eventReaderreader = factory.createXMLEventReader(is);int loopCount = 0;while(reader.hasNext()) {loopCount++;//通过event进行迭代XMLEvent event = reader.nextEvent();if(event.isStartElement()) {//将event转换为Element进行操作StartElement startElement = event.asStartElement();String name = startElement.getName().toString();if(name.equals("book")) {System.out.print(name+":");//获取属性定义Attribute attr = startElement.getAttributeByName(new QName("category"));if(attr!=null) {System.out.println(attr.toString());}}}}System.out.println("基于迭代模型未使用过滤器共循环"+loopCount+"次");} catch (XMLStreamException e) {e.printStackTrace();} finally {if(is!=null)try {is.close();} catch (IOException e) {e.printStackTrace();}if(reader!=null) {try {reader.close();} catch (XMLStreamException e) {e.printStackTrace();}}}}/** * 基于迭代的方式，使用过滤器，提高读取效率FilteredReader */@Testpublic void testStax04() {XMLInputFactory factory = XMLInputFactory.newInstance();InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream("books.xml");XMLEventReader eventReader = null;XMLEventReader filterReader = null;try {//没有过滤器的eventReadereventReader = factory.createXMLEventReader(is);//创建带有过滤器的eventReaderfilterReader = factory.createFilteredReader(eventReader, new EventFilter() {@Overridepublic boolean accept(XMLEvent event) {//指定不被过滤的类型if(event.isStartElement()) {String name = event.asStartElement().getName().toString();if("book".equals(name)) {return true;}}return false;}});int loopCount = 0;while(filterReader.hasNext()) {loopCount++;//通过event进行迭代XMLEvent event = filterReader.nextEvent();if(event.isStartElement()) {//将event转换为Element进行操作StartElement startElement = event.asStartElement();String name = startElement.getName().toString();if(name.equals("book")) {System.out.print(name+":");//获取属性定义Attribute attr = startElement.getAttributeByName(new QName("category"));if(attr!=null) {System.out.println(attr.toString());}}}}System.out.println("使用过滤器迭代，共循环"+loopCount+"次！");} catch (XMLStreamException e) {e.printStackTrace();} finally {try {if(is!=null)is.close();if(eventReader!=null)eventReader.close();if(filterReader!=null)filterReader.close();} catch(Exception e) {e.printStackTrace();}}}