Don't understand how Spring (Boot) Data REST is told to create API endpoints

Question

I have currently have an application that is using Spring Boot and Spring Data. I have my domain objects that were reverse engineered from my database and I have several repositories (classes). Each repository is an interface that extends the CrudRepository.

import org.springframework.data.repository.CrudRepository

interface MyDomainClassRepository extends CrudRepository<MyDomainClass, Integer> {
     private MyDomainClass findByName(String name);
}

At this point I would create a service that would implement these items. The service would then be called by a REST controller.

I wanted to be able to have Spring create my REST API automatically if possible and I found the Spring Data REST project. I found this http://spring.io/guides/gs/accessing-data-rest/ and I can follow that guide, but I don't understand what is enabling the "REST APIs" to be created "automatically". I could understand it if the @RepositoryRestResource annotation caused the API to be created but in that guide it explicitly says

RepositoryRestResource is not required for a repository to be exported. It is only used to change the export details, such as using /people instead of the default value of /persons.

Does including in my POM file and rebuilding "automatically" allow Spring Data to create the REST endpoints?

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-rest</artifactId>
    </dependency>

What keyword, section am I missing that makes it so the API endpoint is created automatically?

Answer 1

Spring Data Rest implements six controllers, in the package org.springframework.data.rest.webmvc:

RepositoryController: handles /

RepositoryEntityController: handles /{repository}

RepositoryPropertyReferenceController: handles /{repository}/{id}/{property} and /{repository}/{id}/{property}/{propertyId}

RepositorySearchController: handles /{repository}/search and /{repository}/search/{repoFunctionName}

ProfileController: handles /profile

RepositorySchemaController: handles /profile/{repository}

They are essentially the same as Spring MVC Controllers, except they are designed to work with Spring Data repositories in a general way

So, if you do GET /foo where foo is the path of your fooRepository, then Spring Data Rest will call RepositoryEntityController.getCollectionResource(), and invoke fooRepository.findAll(...), wrap the result in some HATEOAS objects, then marshal to JSON, using Jackson