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XML:Stax操作XML(基于光标的方式、迭代的方式、XPath的方式)

2015-12-21 16:12 435 查看
STAX

Stax不是采取Dom4j这种全部读取的方式,而是像PULL、Sax的ContentHandler这种一个节点一个节点读取的方式,提供了基于光标的方式、迭代的方式、XPath的方式。这种处理方式的基础就是把XML文档看做一个一个的节点组成:ElementNode、TextNode等节点,每读取到一个节点就生成一个事件或者Element,在XMLStreamConstants中定义。



<?xml version="1.0" encoding="UTF-8"?>

———这种空白地方也是节点———

<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>







public class TestStax {



@Test

publicvoid test01() {

XMLInputFactoryfactory = XMLInputFactory.newInstance();

InputStreamis = null;

try{

is= TestStax.class.getClassLoader().getResourceAsStream("books.xml");

XMLStreamReaderreader = factory.createXMLStreamReader(is);

while(reader.hasNext()){

int type = reader.next();

//判断节点类型是否是开始或者结束或者文本节点,之后根据情况及进行处理

if(type==XMLStreamConstants.START_ELEMENT){

System.out.println(reader.getName());

} elseif(type==XMLStreamConstants.CHARACTERS) {

System.out.println(reader.getText().trim());

} elseif(type==XMLStreamConstants.END_ELEMENT) {

System.out.println("/"+reader.getName());

}

}

}catch (XMLStreamException e) {

e.printStackTrace();

}finally {

try{

if(is!=null)is.close();

}catch (IOException e) {

e.printStackTrace();

}

}

}



@Test

publicvoid test02() {

XMLInputFactoryfactory = XMLInputFactory.newInstance();

InputStreamis = null;

try{

is= TestStax.class.getClassLoader().getResourceAsStream("books.xml");

XMLStreamReaderreader = factory.createXMLStreamReader(is);

while(reader.hasNext()){

inttype = reader.next();

if(type==XMLStreamConstants.START_ELEMENT){


String name =reader.getName().toString();


if(name.equals("book")){


System.out.println(reader.getAttributeName(0)+":"+reader.getAttributeValue(0));

}

}

}

}catch (XMLStreamException e) {

e.printStackTrace();

}finally {

try{

if(is!=null)is.close();

}catch (IOException e) {

e.printStackTrace();

}

}

}



@Test

publicvoid test03() {

XMLInputFactoryfactory = XMLInputFactory.newInstance();

InputStreamis = null;

try{

is= TestStax.class.getClassLoader().getResourceAsStream("books.xml");

XMLStreamReaderreader = factory.createXMLStreamReader(is);

while(reader.hasNext()){

inttype = reader.next();



if(type==XMLStreamConstants.START_ELEMENT){


String name =reader.getName().toString();

if(name.equals("title")){


System.out.print(reader.getElementText()+":");


}


if(name.equals("price")){


System.out.print(reader.getElementText()+"\n");


}

}

}

}catch (XMLStreamException e) {

e.printStackTrace();

}finally {

try{

if(is!=null)is.close();

}catch (IOException e) {

e.printStackTrace();

}

}

}



@Test

publicvoid test04() {

XMLInputFactoryfactory = XMLInputFactory.newInstance();

InputStreamis = null;

try{

is= TestStax.class.getClassLoader().getResourceAsStream("books.xml");

//基于迭代模型的操作方式

XMLEventReaderreader = factory.createXMLEventReader(is);

intnum = 0;

while(reader.hasNext()){

//通过XMLEvent来获取是否是某种节点类型

XMLEvent event =reader.nextEvent();

if(event.isStartElement()){

//通过event.asxxx转换节点


String name =event.asStartElement().getName().toString();


if(name.equals("title")){


System.out.print(reader.getElementText()+":");


}


if(name.equals("price")){


System.out.print(reader.getElementText()+"\n");


}

}

num++;

}

System.out.println(num);

}catch (XMLStreamException e) {

e.printStackTrace();

}finally {

try{

if(is!=null)is.close();

}catch (IOException e) {

e.printStackTrace();

}

}

}



@Test

publicvoid test05() {

XMLInputFactoryfactory = XMLInputFactory.newInstance();

InputStreamis = null;

try{

is= TestStax.class.getClassLoader().getResourceAsStream("books.xml");

//基于Filter的过滤方式,可以有效的过滤掉不用进行操作的节点,效率会高一些

XMLEventReaderreader = factory.createFilteredReader(factory.createXMLEventReader(is),


newEventFilter() {


@Override


publicboolean accept(XMLEvent event) {


//返回true表示会显示,返回false表示不显示


if(event.isStartElement()){


Stringname = event.asStartElement().getName().toString();


if(name.equals("title")||name.equals("price"))


returntrue;


}


returnfalse;


}


});

intnum = 0;

while(reader.hasNext()){

//通过XMLEvent来获取是否是某种节点类型

XMLEventevent = reader.nextEvent();

if(event.isStartElement()){

//通过event.asxxx转换节点

Stringname = event.asStartElement().getName().toString();

if(name.equals("title")){

System.out.print(reader.getElementText()+":");

}

if(name.equals("price")){

System.out.print(reader.getElementText()+"\n");

}

}

num++;

}

System.out.println(num);

}catch (XMLStreamException e) {

e.printStackTrace();

}finally {

try{

if(is!=null)is.close();

}catch (IOException e) {

e.printStackTrace();

}

}

}

}





基于XPath的方式就必须把整个文档镀金内存,这样才能整个搜寻。这种方式适合根据条件或者说路径找到特定的节点。

@Test

publicvoid test06() {

InputStreamis = null;

try{

is= TestStax.class.getClassLoader().getResourceAsStream("books.xml");

//创建文档处理对象

DocumentBuilderdb = DocumentBuilderFactory.newInstance().newDocumentBuilder();

//通过DocumentBuilder创建doc的文档对象

Documentdoc = db.parse(is);

//创建XPath

XPathxpath = XPathFactory.newInstance().newXPath();

//第一个参数就是xpath,第二参数就是文档

NodeListlist = (NodeList)xpath.evaluate("//book[@category='WEB']",doc,XPathConstants.NODESET);

for(inti=0;i<list.getLength();i++) {

//遍历输出相应的结果

Elemente = (Element)list.item(i);

System.out.println(e.getElementsByTagName("title").item(0).getTextContent());

}

}catch (ParserConfigurationException e) {

e.printStackTrace();

}catch (SAXException e) {

e.printStackTrace();

}catch (IOException e) {

e.printStackTrace();

}catch (XPathExpressionException e) {

e.printStackTrace();

}finally {

try{

if(is!=null)is.close();

}catch (IOException e) {

e.printStackTrace();

}

}

}





生成XML

@Test

publicvoid test07() {

try{

XMLStreamWriter xsw =XMLOutputFactory.newInstance().createXMLStreamWriter(System.out);

xsw.writeStartDocument("UTF-8","1.0");

xsw.writeEndDocument();

Stringns = "http://11:dd";

xsw.writeStartElement("nsadfsadf","person",ns);//前缀、名称、命名空间

xsw.writeStartElement(ns,"id");

xsw.writeCharacters("1");

xsw.writeEndElement();

xsw.writeEndElement();

xsw.flush();

xsw.close();

}catch (XMLStreamException e) {

e.printStackTrace();

}catch (FactoryConfigurationError e) {

e.printStackTrace();

}

}



@Test

publicvoid test08() {

InputStreamis = null;

try{

is= TestStax.class.getClassLoader().getResourceAsStream("books.xml");

//创建文档处理对象

DocumentBuilderdb = DocumentBuilderFactory.newInstance().newDocumentBuilder();

//通过DocumentBuilder创建doc的文档对象

Documentdoc = db.parse(is);

//创建XPath

XPathxpath = XPathFactory.newInstance().newXPath();

Transformer tran =TransformerFactory.newInstance().newTransformer();

tran.setOutputProperty(OutputKeys.ENCODING,"UTF-8");

tran.setOutputProperty(OutputKeys.INDENT,"yes");

//第一个参数就是xpath,第二参数就是文档

NodeListlist = (NodeList)xpath.evaluate("//book[title='LearningXML']", doc,XPathConstants.NODESET);

//获取price节点

Elementbe = (Element)list.item(0);

Elemente = (Element)(be.getElementsByTagName("price").item(0));

e.setTextContent("333.9");

Resultresult = new StreamResult(System.out);

//通过tranformer修改节点

tran.transform(newDOMSource(doc), result);

}catch (ParserConfigurationException e) {

e.printStackTrace();

}catch (SAXException e) {

e.printStackTrace();

}catch (IOException e) {

e.printStackTrace();

}catch (XPathExpressionException e) {

e.printStackTrace();

}catch (TransformerConfigurationException e) {

e.printStackTrace();

}catch (TransformerFactoryConfigurationError e) {

e.printStackTrace();

}catch (TransformerException e) {

e.printStackTrace();

}finally {

try{

if(is!=null)is.close();

}catch (IOException e) {

e.printStackTrace();

}

}

}
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