mule read single file from classpath during flow

Question

Is there an easy way to configure a Flow to read a single file from the classpath one time? I don't need to poll for a file. I just need to read a known file and set its contents as the message payload.

Answer 1

Use the set-payload message processor and a MEL expression:

<set-payload value="#[Thread.currentThread().getContextClassLoader().getResourceAsStream('my-file.abc')]" />

Answer 2

For some reason I cannot make the solution proposed by David Dossot to work. I was inspired by this answer and came up with another solution

<spring:bean id="myResource" class="org.apache.commons.io.IOUtils" factory-method="toString">
    <spring:constructor-arg value="classpath:path/to/myResource.txt" type="java.io.InputStream"/>
</spring:bean>

and then you can use set-payload in the following way

<set-payload value="#[app.registry.myResource]" doc:name="Set Payload"/>

which will result in setting the payload with the content of the file as a String.

This method has the advantage that the content of the resource file is loaded only once into a bean of type String. So if your set-payload statement is executed frequently, this could improve performance.