org.jdom2.xpath.XPath類居然標(biāo)注過時，無奈之下只能研究api。
發(fā)現(xiàn)Use XPathFactory/XPathExpression/XPathBuilder instead.
也就是說jdom應(yīng)該是將xpath類的功能進(jìn)行了更加詳細(xì)的分類。
根據(jù)經(jīng)驗進(jìn)行了一些類的測試，最后得出了讀取xml的兩種方式。
第一種方式，通過XPathFactory類讀取xml
xml文件的內(nèi)容如下
- <span style="font-size:14px"><?xml version="1.0"?>
- <?xml-stylesheet type="text/xsl" href="test.xsl"?>
- <homepages xmlns:xlink="http://www.w3.org/1999/xlink">
-
- <homepage xlink:type="simple"
- xlink:>Visit W3C</homepage>
-
- </homepages></span>
通過SAXBuilder獲取document和root
- String path = System.getProperty("user.dir") + "\\src\\com\\xml\\file\\test.xml";
-
- SAXBuilder saxBuilder = new SAXBuilder();
-
- Document document = saxBuilder.build(path);
-
- Element root = document.getRootElement();
建立
XPathFactory類的對象，需要引入jaxen的jar包，我們使用JaxenXPathFactory類來生成XPathFactory
- XPathFactory factory = JaxenXPathFactory.instance();
生產(chǎn)xpath表達(dá)式實例對象，并獲取結(jié)果集
- XPathExpression<Object> objs = factory.compile("http://homepages");
-
- List<Object> objList = objs.diagnose(root, false).getResult();
- String path = System.getProperty("user.dir") + "\\src\\com\\xml\\file\\test.xml";
-
- SAXBuilder saxBuilder = new SAXBuilder();
-
- Document document = saxBuilder.build(path);
-
- Element root = document.getRootElement();
-
- XPathFactory factory = JaxenXPathFactory.instance();
-
- XPathExpression<Object> objs = factory.compile("http://homepages");
-
- List<Object> objList = objs.diagnose(root, false).getResult();
首先來創(chuàng)建一個filter，org.jdom2.filter.Filters中提供給我們了一些過濾器，我們這里選擇元素類型的，F(xiàn)ilter接口的全名是org.jdom2.filter.Filter
- Filter<Element> filter = Filters.element();
- XPathBuilder<Element> builder = new XPathBuilder<Element>("http://homepages", filter);
- XPathFactory factory = JaxenXPathFactory.instance();
-
- XPathExpression<Element> objs = builder.compileWith(factory);
完整代碼是
- String path = System.getProperty("user.dir") + "\\src\\com\\xml\\file\\test.xml";
-
- SAXBuilder saxBuilder = new SAXBuilder();
-
- Document document = saxBuilder.build(path);
-
- Element root = document.getRootElement();
-
- Filter<Element> filter = Filters.element();
-
- XPathBuilder<Element> builder = new XPathBuilder<Element>("http://homepages", filter);
-
- XPathFactory factory = JaxenXPathFactory.instance();
-
- XPathExpression<Element> objs = builder.compileWith(factory);
-
- List<Element> objList = objs.diagnose(root, false).getResult();
獲取帶有命名空間的xml文件內(nèi)容
使用XPathBuilder的setNamespace方法聲明命名空間，Xpath表達(dá)式不需要再寫"http://"，例如
- XPathBuilder<Element> builder = new XPathBuilder<Element>("ci:Teacher", filter);
-
- builder.setNamespace("ci", "http://www.test.cn/tuple");
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