Java Language Tutorial => Parsing single XPath Expression multiple...

Example

In this case, you want to have the expression compiled before the evaluations, so that each call to evaluate does not compile the same expression. The simple syntax would be:

XPath xPath = XPathFactory.newInstance().newXPath(); //Make new XPath
XPathExpression exp = xPath.compile("/documentation/tags/tag[@name='Java']//example");
DocumentBuilder builder = DocumentBuilderFactory.newInstance();
Document doc = builder.parse(new File("path/to/xml.xml")); //Specify XML file path

NodeList javaExampleNodes = (NodeList) exp.evaluate(doc, XPathConstants.NODESET); //Evaluate the XPath from the already-compiled expression

NodeList javaExampleNodes2 = (NodeList) exp.evaluate(doc, XPathConstants.NODESET); //Do it again

Overall, two calls to XPathExpression.evaluate() will be much more efficient than two calls to XPath.evaluate().

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Java Language XML XPath Evaluation Parsing single XPath Expression multiple times in an XML

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