Question

This seems like a pretty common problem, but I haven’t found any sort of consensus on the best method, so I’m posing the question here.

I’m working on a command-line Java application using Spring Batch and Spring. I’m using a properties file along with a PropertyPlaceholderConfigurer, but I’m a little unsure of the best way of handling the properties files for multiple environments (dev, test, etc.). My Googling is only turning up programmatic ways of loading the properties (i.e., in the Java code itself), which doesn’t work for what I’m doing.

One approach I’ve considered is simply placing each environment’s properties file on the server and adding the file’s directory to the classpath via a command-line argument, but I’ve been having trouble loading the file using that method.

The other method I’m considering is to just include all the properties files in the jar and use a system property or command line argument to fill in the name of the properties file at runtime, like this:

<bean id="propertyConfigurer"
    class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
    <property name="locations">
        <list>
            <value>classpath:job.properties.${env}</value>
        </list>
    </property>
</bean>

I lean towards the latter solution, but I’m also looking to see if there’s a better method I’m overlooking.

I should also mention that I have to make the substitution at runtime rather than in the build. The process I’m constrained to use requires a single build which will be promoted through the environments to production, so I’m unable to use substitution ala Maven or Ant.

Answer 1

I agree – it should not be a build time configuration as you want to deploy the exact same payload to the various contexts.

The Locations property of PropertyPlaceHolderConfigurer can take various types of resources. Can also be a filesystem resouce or a url? Thus you could set the location of the config file to a file on the local server and then whenever it runs it would run in the mode specified by the config file on that server. If you have particular servers for particular modes of running this would work fine.

Reading between the lines though it seems you want to run the same application in different modes on the same server. What I would suggest in this case is to pass the location of the config file via a command line parameter. It would be a little tricky to pass this value into the PropertyPlaceHolderConfigurer but would not be impossible.