#xpath SpEL Function

Spring Integration, since version 3.0, provides the built-in #xpath SpEL function, which invokes the XPathUtils.evaluate(…) static method. This method delegates to an org.springframework.xml.xpath.XPathExpression. The following listing shows some usage examples:

<transformer expression="#xpath(payload, '/name')"/>

<filter expression="#xpath(payload, headers.xpath, 'boolean')"/>

<splitter expression="#xpath(payload, '//book', 'document_list')"/>

<router expression="#xpath(payload, '/person/@age', 'number')">
    <mapping channel="output1" value="16"/>
    <mapping channel="output2" value="45"/>
</router>

The #xpath() also supports a third optional parameter for converting the result of the XPath evaluation. It can be one of the String constants (string, boolean, number, node, node_list and document_list) or an org.springframework.xml.xpath.NodeMapper instance. By default, the #xpath SpEL function returns a String representation of the XPath evaluation.

To enable the #xpath SpEL function, you can add the spring-integration-xml.jar to the classpath. You need no declare any components from the Spring Integration XML Namespace.

For more information, see "`Spring Expression Language (SpEL).