book.xml
<?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>
TestStax.java
<span style="font-size:14px;">package com.xml.stax;
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.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
public void test6(){
InputStream is = null;
try {
is = TestStax.class.getClassLoader().getResourceAsStream("books.xml");
//创建文档处理对象
DocumentBuilder db = DocumentBuilderFactory.newInstance().newDocumentBuilder();
/**
* XPath最有用的路径表达式
* nodename 选取此节点的所有子节点
* / 从根节点选取
* // 从匹配选择的当前节点选择文档中的节点,而不考虑它们的位置
* . 选取当前节点
* .. 选取当前节点的父节点
* @ 选取属性
* */
//通过DocumentBuilder 创建doc对象
Document doc = db.parse(is);
XPath path = XPathFactory.newInstance().newXPath();
NodeList list = (NodeList)path.evaluate("//book[@category='WEB']", doc,XPathConstants.NODESET);
for(int i = 0;i<list.getLength();i++){
Element e = (Element)list.item(i);
System.out.println(e.getElementsByTagName("title").item(0).getTextContent());
}
} catch (Exception e) {
e.printStackTrace();
}finally{
if(is != null){
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
@Test
public void test7(){
try {
XMLOutputFactory factory = XMLOutputFactory.newInstance();
//设置此属性可以写入命名空间 否则无法写入
factory.setProperty("javax.xml.stream.isRepairingNamespaces", true);
XMLStreamWriter writer = factory.createXMLStreamWriter(System.out);
writer.writeStartDocument("UTF-8","1.0");
writer.writeEndDocument();
writer.writeStartElement("ns", "book", "http://w3c.school.com/1");
writer.writeAttribute("category", "Web");
writer.writeEndElement();
writer.flush();
writer.close();
} catch (Exception e) {
e.printStackTrace();
}
}
@Test
public void test8(){
InputStream is = null;
try {
is = TestStax.class.getClassLoader().getResourceAsStream("books.xml");
DocumentBuilder db = DocumentBuilderFactory.newInstance().newDocumentBuilder();
Document doc = db.parse(is);
XPath path = XPathFactory.newInstance().newXPath();
Transformer trans = TransformerFactory.newInstance().newTransformer();
trans.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
trans.setOutputProperty(OutputKeys.INDENT,"yes");
NodeList list = (NodeList)path.evaluate("//book[title='Harry Potter']", doc,XPathConstants.NODESET);
Element book = (Element)(list.item(0));
Element price = (Element)(book.getElementsByTagName("price").item(0));
price.setTextContent("400");
Result result = new StreamResult(System.out);
trans.transform(new DOMSource(doc),result);
} catch (Exception e) {
e.printStackTrace();
}finally{
if(is != null){
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}</span>