How to read a file in the system and store in build.gradle for android

Question

I have a specific file that is in my system. I have to read that file and store during the building stage and to be used for API calls.

Below is my code to fetch the file, but do not know how to store it for further use.

def keystorePropertiesFile = "${System.properties['user.home']}${File.separator}.POAKeyStore${File.separator}keystore.properties" as File

How can I achieve this?