Question

I’m attempting to retrieve the value of a single element in an XML file. I’ve truncated the XML to the relevant bit:

<opt>
    <security>
        <check>
            <secure>true</secure>
        </check>
    </security>
</opt>

I’m trying to retrieve ‘true’ from the ‘secure’ element.

I have the following code:

DocumentBuilderFactory domFactory = DocumentBuilderFactory.newInstance();
domFactory.setNamespaceAware(true);
DocumentBuilder builder=domFactory.newDocumentBuilder();
Document doc = builder.parse(file);

XPath xpath=XPathFactory.newInstance().newXPath();
XPathExpression expr=xpath.compile("//opt/security/check/secure/text()");

Object result = expr.evaluate(doc, XPathConstants.STRING);
logger.warn(result.toString());

I’m just trying to get any value for now, and I’ll change the String to Boolean once I get this to work.

My output is blank, I’ve tried a bunch of different things, including following a tutorial and using NodeLists (although that didn’t make very much sense to me since this is a unique element). Am I missing something?

Thanks!

Answer 1

Your code works using the default XPath implementation in my JVM (Sun/Oracle Java on Windows):

>java -version
java version "1.6.0_20"
Java(TM) SE Runtime Environment (build 1.6.0_20-b02)
Java HotSpot(TM) Client VM (build 16.3-b01, mixed mode)

The double forward-slash isn’t necessary in the sample document; as MSDN notes:

An expression that uses the double forward slash (//) indicates a search that can include zero or more levels of hierarchy.

I wonder if this is a namespace issue:

domFactory.setNamespaceAware(true);

You could try omitting this line or providing a NamespaceContext.