1 Theory

Person --> [API/Controller] --> [Service Layer] --> [Data Access Layer] --> [SQL DB]

• Model holds the class
  • We do a bijective map from Model to DB using spring JPA annotation which means the SQL db query to create the associated Model class will be autogenerated
• Controller holds the routes but it calls the functions by instantiating then using the Services (alternatively dependency injection of services)
• Services is just a library of functions but we just put these function in some class called “blehServices”
  • Since the functions in “blehServices” is stateless, it is easy to pack it for dependency injection which creates a blehServices singleton and injects it into the Controller that needs it.
• Data access layer is an interface repository pattern that uses spring JPA

2 Spring patterns

• IOC - Spring’s Application context is the IOC. Increases testability, Decrease coupling and enforces coding to interfaces.
• Proxy - Every object in Spring is wrapped in one or more Proxy. Allow us to give additional functionality.
• Factory - IoC container in the startup is a factory
• Singleton + Prototype - Most Spring bean classes use one of these two patterns.
  Bean classes default to Singleton but with annotations can be Prototype.
• Template - Used in remote calls. Most common are JDBC and REST
  Third parties use the Template pattern to plugin easily to Spring
• MVC - Webpages and RESTFUL services use MVC

3 General

4 API

• @RequestParam ← application/x-www-form-urlencoded
• @RequestBody ← application/json,
• @RequestPart ← multipart/form-data,