Stax处理XML(三)——XPath的使用和写文档、修改文档
(1)XPath的使用 前面讲了Stax处理XML的查找,有基于光标的查找,和基于迭代模型的查找。Stax也支持XPath查找。 /** * XPath的使用 * 查找category为WEB的bookList */ @Test 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对象 XPath xpath = XPathFactory.newInstance().newXPath(); //第一个参数是xpath,第二个参数是文档 //查找category为WEB的bookList 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 el = (Element)list.item(i); System.out.println(el.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(); } } }
XQuery Kick Start (2)写文档:使用XMLStreamWriter创建xml /** * 使用XMLStreamWriter创建xml */ @Test public void test07() { try { XMLStreamWriter xsw = XMLOutputFactory.newInstance().createXMLStreamWriter(System.out); xsw.writeStartDocument("UTF-8","1.0"); xsw.writeEndDocument(); String ns = "http://11:dd"; //三个参数分别是前缀、标签名、命名空间URI xsw.writeStartElement("ns","person",ns); xsw.writeStartElement(ns,"id"); //xsw.writeStartElement("person"); //xsw.writeStartElement("id"); xsw.writeCharacters("1"); xsw.writeEndElement(); xsw.writeEndElement(); xsw.flush(); xsw.close(); } catch (XMLStreamException e) { e.printStackTrace(); } catch (FactoryConfigurationError e) { e.printStackTrace(); } }
输出结果: <?xml version="1.0" encoding="UTF-8"?><ns:person><ns:id>1</ns:id></ns:person> 去掉注释部分后的输出结果: <?xml version="1.0" encoding="UTF-8"?><ns:person><ns:id><person><id>1</id></person> (3)修改文档:使用Transformer更新节点信息 读取文档,修改部分,并打印出文档 /** * 使用Transformer更新节点信息 * 修改标题为Learning XML的书的价格为333.9 */ @Test 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对象 XPath xpath = XPathFactory.newInstance().newXPath(); Transformer tran = TransformerFactory.newInstance().newTransformer(); tran.setOutputProperty(OutputKeys.ENCODING,"UTF-8"); //设置第一行换行 tran.setOutputProperty(OutputKeys.INDENT,"yes"); //第一个参数是xpath,第二个参数是文档 NodeList list = (NodeList)xpath.evaluate("//book[title='Learning XML']",XPathConstants.NODESET); //获取上面所查找书的price节点,并set Element be = (Element)list.item(0); Element el = (Element)(be.getElementsByTagName("price").item(0)); el.setTextContent("333.9"); //通过transformer修改节点 Result result = new StreamResult(System.out); tran.transform(new DOMSource(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(); } } }
<?xml version="1.0" encoding="UTF-8" standalone="no"?> <book category="COOKING"> <book category="CHILDREN"> <book category="WEB"> <book category="WEB"> </bookstore> (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! |