Connect Quarkus (JDBC) to Neon

Quarkus is a Java framework optimized for cloud environments. This guide shows how to connect to Neon from a Quarkus project using the PostgreSQL JDBC driver.

To connect to Neon from a Quarkus application using the Postgres JDBC Driver:

1. Create a Neon Project
2. Create a Quarkus project and add dependencies
3. Configure a PostgreSQL data source
4. Use the PostgreSQL JDBC Driver
5. Run the application

Create a Neon project

If you do not have one already, create a Neon project.

1. Navigate to the Projects page in the Neon Console.
2. Click New Project.
3. Specify your project settings and click Create Project.

Create a Quarkus project

Create a Quarkus project using the Quarkus CLI:

quarkus create app neon-with-quarkus-jdbc \
--name neon-with-quarkus-jdbc \
--package-name com.neon.tech \
--extensions jdbc-postgresql,quarkus-agroal,resteasy-reactive

You now have a Quarkus project in a folder named neon-with-quarkus-jdbc with the PostgreSQL JDBC driver, Agroal datasource implementation, and RESTEasy Reactive extensions installed.

Configure a PostgreSQL data source

Create a .env file in the root of your Quarkus project directory. Configure a JDBC data source using the components of your Neon database connection string and specifying the database kind as shown:

QUARKUS_DATASOURCE_DB_KIND=postgresql
QUARKUS_DATASOURCE_USERNAME=[user]
QUARKUS_DATASOURCE_PASSWORD=[password]
# Note that "jdbc" is prepended, and that "?sslmode=require" is appended to the connection string
QUARKUS_DATASOURCE_JDBC_URL=jdbc:postgresql://[neon_hostname]/[dbname]?sslmode=require

Use the PostgreSQL JDBC Driver

Create a PostgresResource.java file in the same directory as the GreetingResource.java that was generated by Quarkus during project creation. Paste the following content into the PostgresResource.java file:

package com.neon.tech;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.sql.DataSource;
import jakarta.inject.Inject;
import jakarta.ws.rs.GET;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.Produces;
import jakarta.ws.rs.core.MediaType;

@Path("/postgres")
public class PostgresResource {
    @Inject
    DataSource dataSource;

    @GET
    @Path("/version")
    @Produces(MediaType.TEXT_PLAIN)
    public String getVersion() {
        try (Connection connection = dataSource.getConnection();
                Statement statement = connection.createStatement()) {

            ResultSet resultSet = statement.executeQuery("SELECT version()");

            if (resultSet.next()) {
                return resultSet.getString(1);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return null;
    }
}

This code defines a HTTP endpoint that will query the database version and return it as a response to incoming requests.

Run the application

Start the application in development mode using the Quarkus CLI from the root of the project directory:

quarkus dev

Visit localhost:8080/postgres/version in your web browser. Your Neon database's Postgres version will be returned. For example:

PostgreSQL 15.4 on x86_64-pc-linux-gnu, compiled by gcc (Debian 10.2.1-6) 10.2.1 20210110, 64-bit