Stax处理XML,基于迭代模型的查找,关键在于:
使用XMLInputFactory创建XMLEventReader,获取了eventReader之后,(在while循环hasNext中)通过XMLEvent来获取是否是某种节点类型,通过event.asxxx转换节点。
(1)测试一:基于迭代模型的查找
@H_301_12@ /** * 基于迭代模型的查找 */ @Test 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(); } } }
输出结果:
Everyday Italian: 30.00
Harry Potter: 29.99
XQuery Kick Start: 49.99
Learning XML: 39.95
85
(2)测试二: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,然后while只在eventFilter返回的结果集中循环,减少循环次数、提高效率。
- /**
- * 过滤器的使用
- */
- @Test
- 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();
- //eventReader结果集中只显示标题和价格
- if (("title").equals(name) || ("price").equals(name))
- return true;
- }
- return false;
- }
- });
- int num = 0;
- //while只在eventFilter返回的结果集中循环
- 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();
- }
- }
- }
输出结果: Everyday Italian: 30.00 Harry Potter: 29.99 XQuery Kick Start: 49.99 Learning XML: 39.95 8