Java Spring Boot

Read more at Learn the path

Definitions

• Group ID: Identifies the organization. Example: com.google
• Artifact ID: Determines the name of the application.

Compile and Run

# Auto detect changes
gradlew -t :bootJar

# Compile and run
gradlew bootRun

Packages

• Spring Boot DevTools: Provides fast application restarts, LiveReload, and configurations for enhanced development experience.

Three layers architecture

This architecture considers:

• Presentation layer (model + view + controller)
• Business logic (service): it has all the business operations (computation and decision making processes)
• Data access layer (repository): it has all the CRUD operations.

Annotations

• @Component annotation is too generic. Use @Service for business logic layer and @Repository for the data access layer instead. They all turn a class into a Bean. @Controller also derives from @Component.
• @Configuration marks a class as a source of Beans definitions.
• @Autowired wires the class into the Bean that needs it.
• @RestController = @Controller + @ResponseBody. @ResponseBody converts the output to JSON.

Best practices

Dependency injection

• Never ever create an object inside of a class that depends on it. This is called tight coupling and makes unite testing impossible. Instead, use dependency injection.