The previous chapter introduced a new addition to the Spring Framework family—Spring WebFlux. This addition brings reactive programming to the application front and enables non-blocking processing of HTTP requests of all kinds.

In this chapter, we will learn how to access data in a reactive manner using Spring Data modules. This ability is vital for the creation of an entirely reactive and responsive application that leverages all available computing resources most efficiently, delivering the maximum business value and also requiring a minimal operational cost at the same time.

Even if our database of choice does not provide a reactive or asynchronous driver, it is still possible to build a reactive application around it using a dedicated thread pool—this chapter covers how to do this. However, blocking I/O is always discouraged in reactive applications.

In this chapter, we cover the following topics:

• Patterns of data storage and data processing in the modern world
• Pros and cons of synchronous data access
• How Spring Data allows reactive data access and how to use this in reactive applications
• What reactive connectors are available at the moment
• How to adapt blocking I/O to the reactive programming model