Calling a specific service class or controller method of spring boot application using Sparklauncher

Question

In a spring boot application,I have couple of service classes . Each service class is doing some spark transformations. I am testing locally using controller which is staring the sparksession and doing some transformations and closing the session. but how can we call a specific service or a controller method in spring boot to execute using spark launcher. Any help is appreciated.. I am new to spark and java.. A sample example will be very helpful Thanks!! how to call a particular service (dcpayservice.applytransformations() or the controller method to run the spark job