Spring Boot: Up and Running

Chapter 8. Reactive Programming with Project Reactor and Spring WebFlux

This chapter introduces reactive programming, discusses its origins and reasons for being, and demonstrates how Spring is leading the development and advancement of numerous tools and technologies that make it one of the best possible solutions for numerous use cases. More specifically, I demonstrate how to use Spring Boot and Project Reactor to drive database access using SQL and NoSQL databases, integrate reactive types with view technologies like Thymeleaf, and take interprocess communication to unexpected new levels with RSocket.

Code Checkout Checkup

Please check out branch chapter8begin from the code repository to begin.

Introduction to Reactive Programming

While a full treatise on reactive programming could—and has, and will—consume an entire book, it’s critical to understand why it’s such an important concept in the first place.

In a typical service, a thread is created for each request to be handled. Each thread requires resources, and as such, the number of threads that an application can manage is limited. As a somewhat simplified example, if an app can service 200 threads, that application can accept requests from up to 200 discrete clients at once, but no more; any additional attempts to connect to the service must wait for a thread to become available.

Performance for the 200 connected clients may or may not be satisfactory, depending on a number of factors. What is uncontestable is that for ...