I have a simple Spring Boot project (already mentioned here: Replace hsqldb with MySQL)
I would like to configure Hibernate to work with this project. In another project I used to get EntityManager like so:
@PersistenceContext(unitName = "orm-unit")
private EntityManager em;
but there I also have persistence.xml with required configuration.
In Spring Boot I don't even know where to place any configuration files. How to make Hibernate work in this case?
Read the Spring Boot documentation. Looking over 31. Working with SQL databases you will see that you need to configure a DataSource.
DataSource configuration is controlled by external configuration properties in spring.datasource.*. For example, you might declare the following section in application.properties:
spring.datasource.url=jdbc:mysql://localhost/test spring.datasource.username=dbuser spring.datasource.password=dbpass spring.datasource.driver-class-name=com.mysql.jdbc.Driver
You can also configure a datasource in a @Configuration mapped class which implements EnvironmentAware.
JHipster generates a cool database configuration using HikariCP. You can check it out the sample here.
For Hibernate you can configure JPA properties.
You can set spring.jpa.hibernate.ddl-auto explicitly and the standard Hibernate property values are none, validate, update, create, create-drop. Spring Boot chooses a default value for you based on whether it thinks your database is embedded (default create-drop) or not (default none).
For example to create and drop tables you can add the following to your application.properties.
spring.jpa.hibernate.ddl-auto=create-drop
As for EntityManager when you EnableAutoConfiguration you will trigger a JpaBaseConfiguration which will create an entity manager for you.
You can also use a custom EntityManagerFactory.
To take full control of the configuration of the EntityManagerFactory, you need to add a @Bean named ‘entityManagerFactory’. Spring Boot auto-configuration switches off its entity manager based on the presence of a bean of that type.
And btw you can also use a traditional persistence.xml
