Spring Applications

Exercise: Hello Application (Configuration Classes)

1. External Properties
   • Write a configuration file application.properties that contains a property for the adult age
   • Inject the property value into the Hello service to decide which message to return
   • Use a command line option to override the property value
2. Type-safe Properties
   • Implement a configuration class TimesOfDay with properties for the times of day
   • Add the spring-boot-starter-validation starter and use annotations to validate the properties
   • Inject an instance into the Greeting service to generate an appropriate daytime greeting
3. Profiles
   • Add the existing command-line runner TestRunner to the profile dev
   • Implement another command-line runner HelloRunner that asks the user for his name and age, and add it to the profile prod
   • Run the application using the spring.profiles.active command line option

Solution