SpringBoot WebFlux Annotation-based RestAPIs

#springboot #webflux #restapi #annotation

https://grokonez.com/spring-framework/spring-webflux/springboot-webflux-annotation-based-programming-model

Reactive programming is about non-blocking applications. And Spring Framework 5 includes a new spring-webflux module, supports Reactive Streams for communicating backpressure across async components and libraries. So in the tutorial, JavaSampleApproach will guide you through the steps for creating a SpringBoot WebFlux Annotation-based restful APIs.

I. Technologies

– Java: 1.8
– Maven: 3.3.9
– Spring Tool Suite: Version 3.9.0.RELEASE
– Spring Boot: 2.0.0.M4

Spring Boot Starter Webflux
II. Spring WebFlux
Spring Framework 5.0 supports WebFlux with fully asynchronous and non-blocking and does NOT require the Servlet API(Unlike Spring MVC).

Spring WebFlux supports 2 distinct programming models:

Annotation-based with @Controller
Functional with Java 8 lambda style

In the tutorial, we will introduce WebFlux with Annotation-based.
For starting with WebFlux, SpringBoot supports a collection dependency: spring-boot-starter-webflux.

Sample code:


@RestController
@RequestMapping(value="/api/customer")
public class RestControllerAPIs {
    
    @GetMapping("/")
    public Flux getAll() {
    
        ...
    }
    
    @GetMapping("/{id}")
    public Mono getCustomer(@PathVariable Long id) {
        
        ...
    }
}

reactor.core.publisher.Flux: is a standard Publisher representing a reactive sequence of 0..N items, optionally terminated by either a success signal or an error.
reactor.core.publisher.Mono: Mono is a specialized Publisher that emits at most single-valued-or-empty result.
III. Practice
In the tutorial, We create a SpringBoot project as below:

Step to do:

Create SpringBoot project
Create data model
Implement Spring WebFlux APIs
Run and check results
1. Create SpringBoot project
Using SpringToolSuite, create a SpringBoot project with Reactive Web dependency: