Vaadin + Spring Boot + MongoDB + MariaDB MaxScale demo

This example shows how to connect a Vaadin application to MongoDB databases. This file also shows how to use MaxScale to connect the same application to a MariaDB backend using the NoSQL protocol without modifying the app.

Preparing the database

You need MongoDB listening on port 27017 or a MariaDB database and a MaxScale instance with a Listener using the nosqlprotocol protocol.

Setting up the database cluster using Docker

Clone this repository:

git clone https://github.com/alejandro-du/mongodb-vaadin-demo.git

Spin up a MariaDB database and a database proxy (MaxScale):

cd mongodb-vaadin-demo
docker compose up -d

WARNING! These Docker images are not suitable for production!

Run the web application

Build the Java web application using Maven:

mvn package

Run the application:

java -jar target/mongodb-vaadin-demo.jar

Access the application in your browser at http://localhost:9090. Insert some data.

Access the MaxScale GUI at http://localhost:8989/ using the following credentials:

• Username: admin
• Password: mariadb

In the menu, go to the query editor and connect to the database using:

• Listener name: query_router_listener
• Username: user
• Password: password

Inspect the database and query the student table:

select * from student

Or use MariaDB's JSON functions:

select
	json_value(doc, '$.firstName') as firstName,
	json_value(doc, '$.lastName') as lastName,
	id as regNumber
from student

Or if you want to join data with other tables in the database:

select s.*, st.id regNumber
from student st,
    json_table(st.doc, '$'
        columns(
            firstName varchar(255) path '$.firstName',
            lastName varchar(255) path '$.lastName'
        )
    ) as s

To shutdown the database cluster run:

docker compose down

Add -v to the above command if you want to remove the related Docker volumes as well (you'll lose all the configuration and data).