使用JDK自带的Stax操作XML
操作的books.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>
测试类：
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(); } } } }
