Spring Webflux + JPA: Reactive Repositories are not supported by JPA

I don't know about previous support, but as of 09 June 2019, you can absolutely use WebFlux with JPA Repositories!

Your stack doesn't have to be fully reactive. I like WebFlux, but need a relational database.

I have:

• spring-boot-starter-data-redis-reactive
• spring-boot-starter-webflux
• spring-boot-starter-data-jpa

edit: (FYI) code is in Kotlin, but should still work in Java.

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = ["com.example.core.repositories"])
@EnableJpaAuditing
class PersistenceConfig

src/core/models/User

@Entity
@Table(name = "user")
class User(
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "user_id")
    var id: Long,

    @Column(name = "username")
    var username: String,

    @Column(name = "created_date", nullable = false, updatable = false)
    @CreatedDate
    @Temporal(TemporalType.TIMESTAMP)
    val createdDate: Date,

    @Column(name = "modified_date")
    @LastModifiedDate
    @Temporal(TemporalType.TIMESTAMP)
    val modifiedDate: Date
) : Serializable {

    /**
     * This constructor is not to be used. This is for hibernate,
     * which requires an empty constructor.
     */
    constructor() : this(1L, "", "", Date(), Date())

    companion object {
        private const val serialVersionUID = 2398467923L
    }

}

I got the same JPA: Reactive Repositories are not supported by JPA. error when I was still returning mono objects from the Spring Data query like Mono<User>. However, if you remove the Mono wrapper, it should work just fine.

src/core/repositories/UserRepository

@Repository
interface UserRepository: CrudRepository<User, Long> {

    fun findUserByUsername(username: String): User?

}

If you want all the benefits of reactive, async / non-blocking, you'll need to make the whole stack async / non-blocking. JDBC is indeed inherently a blocking API, so you can't build a fully reactive / non-blocking app if you need to access the database through JDBC.

But you still you need relational database then will recommend to use rxjava2-jdbc and here is full example of using RxJava and RxJava jdbc spring-webflux-async-jdbc-sample

Seems currently Spring webflux support Mongodb, Redis, etc nosql reactive so instead of JPA use spring-boot-starter-data-mongodb-reactive .