java - 在java中使用xpath查询xml

Question

我正在尝试使用 java 中的 xpath 对巨大的 XML 文件进行一些查询，这是我的代码：

         DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory.newInstance();
         docBuilderFactory.setNamespaceAware(true);

         DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
         Document document = docBuilder.parse(new File("test.xml"));

         XPath xpath = XPathFactory.newInstance().newXPath();

         String xPath = "/*/*[@id='ABCD']/*/*";

         XPathExpression expr = xpath.compile(xPath);
         NodeList result = (NodeList)expr.evaluate(document, XPathConstants.NODESET);

代码的最后一行花了很多时间，我不知道为什么，没有这行程序在 1 秒内完成，在 40 秒内完成。我也试过 XOM，它也不起作用。在 java 中的巨大 XML 文件中进行更快查询的替代方法是什么？

Answer 1

Use SAX, not DOM. Because SAX requires much less memory than DOM, because SAX does not construct an internal representation (tree structure) of the XML data, as a DOM does. Instead, SAX simply sends data to the application as it is read; your application can then do whatever it wants to do with the data it sees.

For details read.

http://docs.oracle.com/javase/tutorial/jaxp/sax/index.html