Overview

Implementation with and without using Spring Data JPA

JPA without using Spring Data JPA

Implementation

Inject EntityMangager into Repository implementation class. Each operation method is implemented in the Repository. Each method delegate actual process to EntityManager. Their signatures imitate ones of JpaRepository provided by Spring Data JPA.

This is based on Spring Boot and @EnableJpaRepositories is enabled. To avoid using Spring Data JPA, I use @Profile on Service classes. I have 2 Service classes. One is for without Spring Data JPA, the other is for Spring Data JPA.

How to run

1. Set profile "without-datajpa" into application.yml
2. Run main method in Application
3. Access http://localhost:8080/rooms
4. Confirm JPA mode at the bottom of web pages. It might show RoomServiceImpl.

JPA with using Spring Data JPA

Implementation

Basic usage of Spring Data JPA. Spring Boot helps configurations for Spring Data JPA. But I dare to have configuration code for Spring Data JPA for learning its mechanism.

How to run

1. Set profile empty or anything other than "without-datajpa" into application.yml
2. Run main method in Application
3. Access http://localhost:8080/rooms
4. Confirm JPA mode at the bottom of web pages. It might show RoomServiceJpaImpl.