An introduction to Spring Data(Reactive)

Spring Data also added Reactive Streams support into the existing projects.

NoSQL support, such as Redis, MongoDB, Couchbase and Cassandra are the first-class citizen in the WebFlux world.

RDBMS support, such as JDBC and JPA are designated for blocking access will not work under the new WebFlux applications.

To resolve the problem, Spring team leads a new reactive specification R2dbc to access RDBMS. Similar to the JDBC specification, R2dbc provides a collection of standardized APIs and allow you to implement your own database drivers through r2dbc-spi. Currently, MySQL(and MariaDB), MSSQL, Oracle, H2, PostgresSQL have got support. Check the R2dbc website for more info.

Reactive Repository

Similar to the existing Repository and it derived interfaces for blocking cases such as PagingAndSortingRepository and CrudRepository. Spring Data Commons add variants for reactive cases, such as ReactiveSortingRepository and ReactiveCrudRepository.

Note: There is no Paging variant for reactive interfaces.

The Spring Data subprojects could have its specific top-level Repository, such as Spring Data Mongo provides ReactiveMongoRepository.

@NoRepositoryBean
public interface ReactiveMongoRepository<T,ID>
extends ReactiveSortingRepository<T,ID>, ReactiveQueryByExampleExecutor<T>{...}

To create your Repository , create an interface to extend ReactiveCrudRepository or ReactiveSortingRepository or a subproject specific Repository. For example:

interface PostRepository extends ReactiveCrudRepository{}
interface PostRepository extends ReactiveSortingRepository{}
interface PostRepository extends ReactiveMongoRepository{}

RxJava 2 and RxJava 3 Support

The reactive Repository supports RxJava 2 and 3 variants.

• For RxJava 2, there is a RxJava2CrudRepository and RxJava2SortingRepository.
• For RxJava 3, there is a RxJava3CrudRepository and RxJava3SortingRepository.

To use RxJava 2/3 instead of Reactor, just need to declare your Repositoryto extends RxJava3CrudRepository or RxJava3SortingRepository. For example:

interface PostRepository extends RxJava3SortingRepository{}