java_XML_STAX
xml文件
<?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>
import java.io.IOException;import java.io.InputStream;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.stream.EventFilter;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamConstants;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;
import javax.xml.stream.events.XMLEvent;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathFactory;
import org.junit.Test;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
public class TestStax {
@Test
/**
* 读取xml的<book category="COOKING">
* 获取book元素的属性和属性值
*/
public void test02() {
XMLInputFactory factory = XMLInputFactory.newInstance();
InputStream is = null;
try {
is = TestStax.class.getClassLoader().getResourceAsStream("books.xml");
XMLStreamReader reader = 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) {
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
/**
* 读取title和price标签的值
<title lang="en">Everyday Italian</title>
<price>30.00</price>
*/
public void test03() {
XMLInputFactory factory = XMLInputFactory.newInstance();
InputStream is = null;
try {
is = TestStax.class.getClassLoader().getResourceAsStream("books.xml");
XMLStreamReader reader = factory.createXMLStreamReader(is);
while(reader.hasNext()) {
int type = 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
/**
* 使用XMLEvent来读取title和price标签的值
* <title lang="en">Everyday Italian</title>
* <price>30.00</price>
*/
public void test04() {
XMLInputFactory factory = XMLInputFactory.newInstance();
InputStream is = null;
try {
is = TestStax.class.getClassLoader().getResourceAsStream("books.xml");
//基于迭代模型的操作方式
XMLEventReader reader = factory.createXMLEventReader(is);
int num = 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
/**
* 使用Filter过滤的不需要操作的元素，提高效率
* 同时使用XMLEvent
*/
public void test05() {
XMLInputFactory factory = XMLInputFactory.newInstance();
InputStream is = 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
XMLEventReader reader = factory.createFilteredReader(factory.createXMLEventReader(is),
new EventFilter() {
@Override
public boolean accept(XMLEvent event) {
//返回true表示会显示，返回false表示不显示
if(event.isStartElement()) {
String name = event.asStartElement().getName().toString();
if(name.equals("title")||name.equals("price"))
return true;
}
return false;
}
});
int num = 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
/**
* 使用XPath和表达式精确定位元素(基于document的形式，在文档很大的情况下效率差)
* 表达式：//book[@category='WEB']
* 意义：查找book元素的属性等于WEB的节点
*/
public void test06() {
InputStream is = null;
try {
is = TestStax.class.getClassLoader().getResourceAsStream("books.xml");
//创建文档处理对象
DocumentBuilder db = DocumentBuilderFactory.newInstance().newDocumentBuilder();
//通过DocumentBuilder创建doc的文档对象
Document doc = db.parse(is);
//创建XPath
XPath xpath = XPathFactory.newInstance().newXPath();
//第一个参数就是xpath,第二参数就是文档
NodeList list = (NodeList)xpath.evaluate("//book[@category='WEB']", doc, XPathConstants.NODESET);
for(int i=0;i<list.getLength();i++) {
//遍历输出相应的结果
Element e = (Element)list.item(i);
System.out.println(e.getElementsByTagName("title").item(0).getTextContent());
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if(is!=null) is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
@Test
/**
* 使用XMLStreamWriter生成XML
*/
public void test07() {
try {
XMLStreamWriter xsw = XMLOutputFactory.newInstance().createXMLStreamWriter(System.out);
xsw.writeStartDocument("UTF-8","1.0");
xsw.writeEndDocument();
String ns = "http://11:dd";
xsw.writeStartElement("person");
xsw.writeAttribute("name", "张三");
xsw.writeStartElement("age");
xsw.writeCharacters("1");
xsw.writeEndElement();
xsw.writeEndElement();
xsw.flush();
xsw.close();
} catch (Exception e) {
e.printStackTrace();
}
}
@Test
/**
* 使用Xpath定位元素并通过Transformer修改其中元素的值
*/
public void test08() {
InputStream is = null;
try {
is = TestStax.class.getClassLoader().getResourceAsStream("books.xml");
//创建文档处理对象
DocumentBuilder db = DocumentBuilderFactory.newInstance().newDocumentBuilder();
//通过DocumentBuilder创建doc的文档对象
Document doc = db.parse(is);
//创建XPath
XPath xpath = 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
NodeList list = (NodeList)xpath.evaluate("//book[title='Learning XML']", doc,XPathConstants.NODESET);
//获取price节点
Element be = (Element)list.item(0);
Element e = (Element)(be.getElementsByTagName("price").item(0));
e.setTextContent("333.9");
Result result = new StreamResult(System.out);
//通过tranformer修改节点
tran.transform(new DOMSource(doc), result);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if(is!=null) is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
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