How to persist when using Spring Boot with JPA

Question

I'm used to using Spring Roo to generate my entities and having it handle injecting the entityManager as well as the persist and other methods via AspectJ classes. Now I'm trying to use Spring Boot to do something simple that will write things to the database ...

@Entity
@Table(name = "account")
public class Account { 

  transient EntityManager entityManager;

  @Id
  @GeneratedValue
  private Long id;

  @Column(name = "username", nullable = false, unique = true)
  private String username;

  @Column(name = "password", nullable = false)
  private String password;

  ... getters and setters

  @Transactional
  public void persist() {
    if (this.entityManager == null) this.entityManager = entityManager();
    this.entityManager.persist(this);
  }

  @Transactional
  public Account merge() {
    if (this.entityManager == null) this.entityManager = entityManager();
    Account merged = this.entityManager.merge(this);
    this.entityManager.flush();
    return merged;
  }

When I'm calling persist or merge, entityManager is obviously null.

I've also tried adding implements CrudRepository to the Account class to see it'll give me that functionality via a Default Implementation, but what I'm getting is simply empty classes that needs to be filled in.

I've had a look at the Spring Boot docs, they cover it very briefly omitting just enough detail to so that it's not obvious what I'm missing.

I have an Application class that bootstraps the application:

@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application {

  public static void main(String[] args) throws Exception {
    SpringApplication.run(Application.class, args);
  }

}

My properties file looks like this:

spring.application.name: Test Application

spring.datasource.url: jdbc:mysql://localhost/test
spring.datasource.username=root
spring.datasource.password=
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.jpa.hibernate.ddl-auto=update

This database is automatically being created thanks to the ddl-auto=update property

What is the correct way to persist entities in Spring Boot + JPA and if what I've done is correct so far, how do I "autowire" or auto-create the entityManager?

How to persist when using Spring Boot with JPA

3 Answers