Spring Boot insert sample data into database upon startup

Question

What is the right way for creating test data upon server startup and inserting them into the database (I'm using a JPA/JDBC backed Postgres instance).

Preferably in form of creating Entities and having them persisted through a Repository interface rather than writing plain SQL code. Something like RoR's Rake db:seed helper.

If the framework exposes a hook for doing stuff when all the beans have been injected and the database is ready, that could also work.

Don't forget to accept /upvote the answer if it helped you. – Cepr0 Jun 27 '17 at 05:02 — Cepr0, Jun 27 '17 at 05:02

Cepr0 · Accepted Answer · 2018-07-12T17:33:15.090

You can catch ApplicationReadyEvent then insert demo data, for example:

@Component
public class DemoData {

    @Autowired
    private final EntityRepository repo;

    @EventListener
    public void appReady(ApplicationReadyEvent event) {

        repo.save(new Entity(...));
    }
}

Or you can implement CommandLineRunner or ApplicationRunner, to load demo data when an application is fully started:

@Component
public class DemoData implements CommandLineRunner {

    @Autowired
    private final EntityRepository repo;

    @Override
    public void run(String...args) throws Exception {

        repo.save(new Entity(...));
    }
}

@Component
public class DemoData implements ApplicationRunner {

    @Autowired
    private final EntityRepository repo;

    @Override
    public void run(ApplicationArguments args) throws Exception {

        repo.save(new Entity(...));
    }
}

Or even implement them like a Bean right in your Application (or other 'config') class:

@SpringBootApplication
public class Application {

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

    @Bean
    public CommandLineRunner demoData(EntityRepository repo) {
        return args -> { 

            repo.save(new Entity(...));
        }
    }
}

And what if I want to impersonate o user because for example I have secured methods? Can you update your example? — Alexius DIAKOGIANNIS, Nov 04 '19 at 20:18

score 8 · Answer 2 · answered Jun 25 '17 at 20:09

8

From Spring documentation: http://docs.spring.io/spring-boot/docs/1.5.4.RELEASE/reference/htmlsingle/#howto-database-initialization

Initialize a database using Hibernate A file named import.sql in the root of the classpath will be executed on startup if Hibernate creates the schema from scratch (that is if the ddl-auto property is set to create or create-drop). This can be useful for demos and for testing if you are careful, but probably not something you want to be on the classpath in production. It is a Hibernate feature (nothing to do with Spring).

answered Jun 25 '17 at 20:09

Moshe Arad

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What is meant by root of the classpath ? the root of the src folder ? cause I think this definition is rather dependent on the build tool/platform. – Paghillect Jun 25 '17 at 20:36
If you are using Maven, then a folder like: /src/main/resources @Parsoa – Moshe Arad Jun 25 '17 at 20:40
Thanks. Anyway this approach seems quite error prone and time consuming for the amount of data I need to insert. I'd like it better if there was a Java solution. – Paghillect Jun 25 '17 at 20:45
This is the only solution to what you are trying to achieve according to spring boot documentation – Moshe Arad Jun 25 '17 at 20:48

score 4 · Answer 3 · answered Apr 20 '18 at 09:39

You can do like this

    @SpringBootApplication
    public class H2Application {

        public static void main(String[] args) {
            SpringApplication.run(H2Application.class, args);
        }

        @Bean
        CommandLineRunner init (StudentRepo studentRepo){
            return args -> {
                List<String> names = Arrays.asList("udara", "sampath");
                names.forEach(name -> studentRepo.save(new Student(name)));
            };
        }
    }

Spring Boot insert sample data into database upon startup

3 Answers3

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