XML：Stax操作XML（基于光标的方式、迭代的方式、XPath的方式）
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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(); } } } （编辑：李大同） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |