Spring-data-jpa-tutorial

Define Entity

• @Entity annotation on a class indicates it's a JPA entity. It means this class is mapped to a table in the database.
• @Id annotation indicates it's object Id or primary key in the database table.
• @GeneratedValue indicates that the Id is automatically generated.

Defining a repository

• Define a interface e.g. CustomerRepository extends CRUDRepository which provides serveral default methods for saving, getting, updating and deleting the entity.
• You just define the interfae and Spring Data JPA creates an implementation when you run the application.

Create an application

• @SpringBootApplication - Mark application class with this annotation and it consists of servral other annotation.
  • @Configuration: Tags the class as a source of bean definitions for the application context.
  • @EnableAutoConfiguration: Tells Spring Boot to start adding beans based on classpath settings, other beans, and various property settings.
  • @ComponentScan: Tells Spring to look for other components, configurations, and services in the e.g. com/example package, letting it find the controllers.

Reference

Spring Tutorials - Accessing Data JPA