Mastering Reactive Pagination with Spring Boot and MongoDB

Written by: Tushar Sharma;

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As we delve into the realms of sophisticated data management, we will be harnessing the strengths of Spring Boot, the agility of MongoDB, and the responsiveness of reactive programming to implement an efficient pagination system. Pagination is a critical feature, instrumental in enhancing user experience and application performance. By the end of this guide, you'll have a deep understanding of reactive pagination, equipping you with the skills to manage large data sets with ease and proficiency. Let's get started.

Create a New Spring Boot Application

Go to Start Initializr and create a new Spring Boot Application.

Select the following :

Project	Gradle - Groovy
Spring Boot	3.1.2
Packaging	Jar
Java	17

build.gradle

Build the project and then open it in your favourite editor.

$ gradle build

Setup MongoDB locallly

We'll use docker-compose to spin up a local instance of MongoDB

docker-compose.yml

init-mongo.js

To start the cluster:

$ docker-compose up

Configure MongDB

Create an application-local.properties file in the resources folder with the following configuration. We have to add -Dspring.profiles.active=local to vm options to use this config file.

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

Create an Entity

Create a Product entity in the model.

Product.java

Create a Repository

Create a ProductRepository in the repository package which extends ReactiveSortingRepository.

ProductRepository.java

Create a Service

Create a ProductService class in the service package to interact with the repository.

ProductService.java

Create a Controller

Create a ProductController in the controller package to handle HTTP requests.

ProductController.java

Running the Application

Create a GET request for pagination entries: http://localhost:8080/paginaged-products?page=0&size=2

[
    {
        "id": 1,
        "name": "Product1"
    },
    {
        "id": 4,
        "name": "Product4"
    }
]

Create a GET request for getting all entries: http://localhost:8080/products

You can also verify the data inside mongoDB

$ docker ps 
<CONTAINER_ID> mongo:latest

$ docker exec -it <CONTAINER_ID> bash
# mongosh -u username -p password
# use testdb
# show collections