Build a Reactive Spring WebFlux REST API with MongoDB in Minutes

Introduction

Spring 5 fully supports reactive development through Spring WebFlux.

This article skips theory and directly creates a reactive RESTful API demo using Spring Boot 2.0 and MongoDB to quickly illustrate how reactive code is written.

Example Code

(1) Create Project

The easiest way is to initialize a project at http://start.spring.io .

Group: com.example

Artifact: webflux-demo

Dependencies: Reactive Web and Reactive MongoDB.

(2) Connect to Database

MongoDB can be run in a Docker container.

Add the connection string to application.properties:

spring.data.mongodb.uri=mongodb://localhost:27017/webflux_demo

(3) Create Model

(4) Create DAO

The DAO extends the reactive base class, automatically providing CRUD capabilities without additional code.

(5) Create Controller

The controller implements basic CRUD operations; the return types are reactive, e.g., Flux<Blog> instead of List<Blog>.

Run and Test

Start the application: mvn spring-boot:run Use Postman to call the API and perform create, read, update, and delete operations. Screenshots illustrate each step.

Conclusion

Spring WebFlux provides a powerful reactive model that can improve performance while keeping a familiar programming style. The demo shows how simple reactive coding can be, but mastering Flux and Java 8 features such as lambdas and streams is essential.