native-multiple-databases

1. Introduction

This sample project show how to use multiple database with spring boot and get it running with native images, successfully.

1.1 Requirements

Uses Spring Boot 3.2.0 and GraalVM 21. Uses PostgreSQL DB on localhost. Adopt database to your needs.

Spring Boot 3.2.0 was choosen on purpose, because

• 3.2.1 has an issue with OAuth: spring-projects/spring-security#14362
• 3.2.2 has an issue with Unpaged: spring-projects/spring-data-commons#3025

1.2 Usage

Compile with mvn -Pnative native:compile. Run by executing native platform binary from directory target.

After application has been started it will create an entry in table mydata of both databases by processing code in DatabaseApplication which is annotated with @PostConstruct.

2. Database setup

Two datasources are configured in application.yaml:

graal1:
  datasource:
    jdbcUrl: jdbc:postgresql://localhost:5432/graal
    driverClassName: org.postgresql.Driver
    username: postgres
    password: postgres

graal2:
  datasource:
    jdbcUrl: jdbc:postgresql://localhost:5432/graal2
    driverClassName: org.postgresql.Driver
    username: postgres
    password: postgres

Pay attention to parameter @Qualifier("graalPMT")PersistenceManagedTypes persistenceManagedTypes of LocalContainerEntityManagerFactoryBean in database configurations. This is required to prevent Not a managed type exception message, heavily documented on StackOverflow when running as a native app.

Spring documentation about it can be found here: https://docs.spring.io/spring-framework/reference/core/aot.html#aot.bestpractices.jpa