Creating a reactive data repository

Earlier in Chapter 3, Querying for Data with Spring Boot, we built an easy-to-read data repository by extending JpaRepository from Spring Data JPA. For Spring Data R2DBC, let’s write something like this:

public interface EmployeeRepository extends //
  ReactiveCrudRepository<Employee, Long> {}

This code can be described as follows:

• EmployeeRepository: The name for our Spring Data repository.
• ReactiveCrudRepository: Spring Data Commons’ base interface for any reactive repository. Note that this isn’t specific to R2DBC but instead for ANY reactive Spring Data module.
• Employee: The domain type for this repository (which we’ll code further in the chapter).
• Long: The primary key’s type.

In the previous chapter, we scratched together an Employee domain type using a Java 17 record. However, to interact with our database, we need something a little more detailed than that...