Spring Data Rest provides a very simple option to expose CRUD RESTful services around data repositories.

Some of the important features of Spring Data Rest include the following:

• Exposing the REST API around Spring Data repositories
• Support for pagination and filtering
• Understanding query methods in Spring Data repositories and exposing them as search resources
• Among the frameworks supported are JPA, MongoDB, and Cassandra
• Options to customize the resources are exposed by default

We will start by including the Spring Boot Data Rest starter in our pom.xml:

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

We can make UserRepository expose the REST service by adding a simple annotation, as shown in the following snippet:

    @RepositoryRestResource(collectionResourceRel = "users", path =
     "users")
    public interface UserRepository 
    extends PagingAndSortingRepository<User, Long> {

Important things to note are as follows:

• @RepositoryRestResource: The annotation used to expose a repository using REST
• collectionResourceRel = "users": The collectionResourceRel value to be used in the generated links
• path = "users": The path under which the resource has to be exposed

When we launch SpringDataJpaFirstExampleApplication as a Java application, the following can be seen in the log:

s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
o.s.b.w.servlet.ServletRegistrationBean : Mapping servlet: 'dispatcherServlet' to [/]
o.s.b.w.servlet.FilterRegistrationBean : Mapping filter: 'characterEncodingFilter' to: [/*]
s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto ****
o.s.d.r.w.RepositoryRestHandlerMapping : Mapped "{[/{repository}], methods=[OPTIONS]
o.s.d.r.w.RepositoryRestHandlerMapping : Mapped "{[/{repository}], methods=[HEAD]
o.s.d.r.w.RepositoryRestHandlerMapping : Mapped "{[/{repository}], methods=[GET]
o.s.d.r.w.RepositoryRestHandlerMapping : Mapped "{[/{repository}], methods=[POST]
o.s.d.r.w.RepositoryRestHandlerMapping : Mapped "{[/{repository}/{id}], methods=[OPTIONS]
o.s.d.r.w.RepositoryRestHandlerMapping : Mapped "{[/{repository}/{id}/{property}]
o.s.d.r.w.RepositoryRestHandlerMapping : Mapped "{[/{repository}/search], methods=[GET]

The preceding log shows that the Spring MVC DispatcherServlet is launched and ready to serve different request methods and URIs.