multiple datasources using Spring Boot

Connects to multiple datasources

This example demostrates how to connect to multiple datasources in same spring boot project

Databases and Migration Tools used

• Postgresql

• MySQL

• Liquibase - DataBase Migration Tool for Postgres Database

• Flyway - DataBase Migration Tool for MySQL Database

• Swagger - http://localhost:8080/swagger-ui.html

Notes

Postgres Database supports Sequences where as MySQL doesn't supports it hence we need to use Identity Generation value Strategy

• Flow as soon as application is started first liquibase and flyway database migrations are executed

• As soon as application is ready bootstrapping of data is done using @EventListener(ApplicationReadyEvent.class)

• Data from both databases are retrieved in API and merged as response

• Json serialization and deSerialization is done using @JsonTest

• When we set HikariDataSource manually we need to set app.datasource._______.hikari.autoCommit=false

Upgrade Notes to Spring Boot 3.x

• Hibernate 6 By default enables pool-lo sequencing strategy with table_seq name instead of hibernate_seq with allocation size 50

• javax.persistance is moved to jakarta.persistance

• added validation starter