1. Getting Started
2. What you will need
3. Solution
4. Writing the App
5. Testing the Application
6. Running the Application
7. Using Postgresql
8. Next steps
9. Help with Micronaut

Access a database with JPA and Hibernate

Learn how to access a database with JPA and Hibernate using Micronaut.

Authors: Iván López, Sergio del Amo

Micronaut Version: 2.5.0

1. Getting Started

In this guide we are going to create a Micronaut app written in Java.

In this guide, we are going to write a Micronaut application that exposes some REST endpoints and store data in a database using JPA and Hibernate.

2. What you will need

To complete this guide, you will need the following:

Some time on your hands
A decent text editor or IDE
JDK 1.8 or greater installed with JAVA_HOME configured appropriately

3. Solution

We recommend that you follow the instructions in the next sections and create the app step by step. However, you can go right to the completed example.

Download and unzip the source

4. Writing the App

Create an app using the Micronaut Command Line Interface or with Micronaut Launch.

mn create-app example.micronaut.micronautguide --build=maven --lang=java

If you don’t specify the --build argument, Gradle is used as a build tool.
If you don’t specify the --lang argument, Java is used as a language.

The previous command creates a Micronaut app with the default package example.micronaut in a folder named micronautguide.

If you are using Java or Kotlin and IntelliJ IDEA, make sure you have enabled annotation processing.

4.1. Data Source configuration

Add the following dependencies:

pom.xml

<dependency> (1)
    <groupId>io.micronaut.sql</groupId>
    <artifactId>micronaut-hibernate-jpa</artifactId>
    <scope>compile</scope>
</dependency>
<dependency> (2)
    <groupId>io.micronaut.sql</groupId>
    <artifactId>micronaut-jdbc-hikari</artifactId>
    <scope>compile</scope>
</dependency>
<dependency> (3)
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
    <scope>runtime</scope>
</dependency>

1	Configures Hibernate/JPA EntityManagerFactory beans.
2	Configures SQL DataSource instances using Hikari Connection Pool.
3	Add dependency to in-memory H2 Database.

Define the data source in src/main/resources/application.yml.

src/main/resources/application.yml

datasources:
  default:
    url: ${JDBC_URL:`jdbc:h2:mem:default;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE`}
    username: ${JDBC_USER:sa}
    password: ${JDBC_PASSWORD:""}
    driverClassName: ${JDBC_DRIVER:org.h2.Driver}

This way of defining the datasource properties means that we can externalize the configuration, for example for production environment, and also provide a default value for development. If the environment variables are not defined Micronaut will use the default values.
Also keep in mind that it is necessary to escape the : in the connection url using back ticks `.

4.2. JPA configuration

Add the next snippet to src/main/resources/application.yml to configure JPA:

src/main/resources/application.yml

jpa:
  default:
    properties:
      hibernate:
        hbm2ddl:
          auto: update
        show_sql: true

4.3. Domain

Create the domain entities:

src/main/java/example/micronaut/domain/Genre.java

package example.micronaut.domain;

import com.fasterxml.jackson.annotation.JsonIgnore;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToMany;
import javax.persistence.Table;
import javax.validation.constraints.NotNull;
import java.util.HashSet;
import java.util.Set;

@Entity
@Table(name = "genre")
public class Genre {

    public Genre() {}

    public Genre(@NotNull String name) {
        this.name = name;
    }

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

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

    @JsonIgnore
    @OneToMany(mappedBy = "genre")
    private Set<Book> books = new HashSet<>();

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Set<Book> getBooks() {
        return books;
    }

    public void setBooks(Set<Book> books) {
        this.books = books;
    }

    @Override
    public String toString() {
        return "Genre{" +
            "id=" + id +
            ", name='" + name + '\'' +
            '}';
    }
}

The previous domain has a OneToMany relationship with the domain Book.

src/main/java/example/micronaut/domain/Book.java

package example.micronaut.domain;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.ManyToOne;
import javax.persistence.Table;
import javax.validation.constraints.NotNull;

@Entity
@Table(name = "book")
public class Book {

    public Book() {}

    public Book(@NotNull String isbn, @NotNull String name, Genre genre) {
        this.isbn = isbn;
        this.name = name;
        this.genre = genre;
    }

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long id;

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

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

    @ManyToOne
    private Genre genre;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getIsbn() {
        return isbn;
    }

    public void setIsbn(String isbn) {
        this.isbn = isbn;
    }

    public Genre getGenre() {
        return genre;
    }

    public void setGenre(Genre genre) {
        this.genre = genre;
    }

    @Override
    public String toString() {
        return "Book{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", isbn='" + isbn + '\'' +
                ", genre=" + genre +
                '}';
    }
}

4.4. Application Configuration

Create an interface to encapsulate the application configuration settings:

src/main/java/example/micronaut/ApplicationConfiguration.java

package example.micronaut;

import javax.validation.constraints.NotNull;

public interface ApplicationConfiguration {

    @NotNull Integer getMax();
}

In Micronaut, like Spring Boot and Grails, you can create type safe configuration by creating classes that are annotated with @ConfigurationProperties.

Create a ApplicationConfigurationProperties class:

src/main/java/example/micronaut/ApplicationConfigurationProperties.java

package example.micronaut;

import io.micronaut.context.annotation.ConfigurationProperties;
import io.micronaut.core.annotation.NonNull;

@ConfigurationProperties("application") (1)
public class ApplicationConfigurationProperties implements ApplicationConfiguration {

    protected final Integer DEFAULT_MAX = 10;

    @NonNull
    private Integer max = DEFAULT_MAX;

    @Override
    @NonNull
    public Integer getMax() {
        return max;
    }

    public void setMax(@NonNull Integer max) {
        if(max != null) {
            this.max = max;
        }
    }
}

1	@ConfigurationProperties` annotation takes a configuration prefix.

You can override max if you add to your src/main/resources/application.yml:

src/main/resources/application.yml

application:
  max: 50

4.5. Repository Access

To mark the transaction demarcations, we use the Java EE 7 javax.transaction.Transactional annotation.

To use it, you have to include the micronaut-data-processor dependency in your annotation processor configuration:

pom.xml

<!-- Add the following to your annotationProcessorPaths element -->
<path>
    <groupId>io.micronaut.data</groupId>
    <artifactId>micronaut-data-hibernate-jpa</artifactId>
</path>

Next, create an interface to define the operations to access the database:

src/main/java/example/micronaut/GenreRepository.java

package example.micronaut;

import example.micronaut.domain.Genre;

import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;
import java.util.List;
import java.util.Optional;

public interface GenreRepository {

    Optional<Genre> findById(@NotNull Long id);

    Genre save(@NotBlank String name);

    Genre saveWithException(@NotBlank String name);

    void deleteById(@NotNull Long id);

    List<Genre> findAll(@NotNull SortingAndOrderArguments args);

    int update(@NotNull Long id, @NotBlank String name);
}

The implementation:

src/main/java/example/micronaut/GenreRepositoryImpl.java

package example.micronaut;

import example.micronaut.domain.Genre;
import javax.inject.Singleton;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceException;
import javax.persistence.TypedQuery;
import javax.transaction.Transactional;
import io.micronaut.transaction.annotation.ReadOnly;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;
import java.util.Arrays;
import java.util.List;
import java.util.Optional;

@Singleton (1)
public class GenreRepositoryImpl implements GenreRepository {

    private final EntityManager entityManager;  (2)
    private final ApplicationConfiguration applicationConfiguration;

    private final static List<String> VALID_PROPERTY_NAMES = Arrays.asList("id", "name");

    public GenreRepositoryImpl(EntityManager entityManager,
                               ApplicationConfiguration applicationConfiguration) { (2)
        this.entityManager = entityManager;
        this.applicationConfiguration = applicationConfiguration;
    }

    @Override

    @ReadOnly  (3)
    public Optional<Genre> findById(@NotNull Long id) {
        return Optional.ofNullable(entityManager.find(Genre.class, id));
    }

    @Override
    @Transactional  (4)
    public Genre save(@NotBlank String name) {
        Genre genre = new Genre(name);
        entityManager.persist(genre);
        return genre;
    }

    @Override
    @Transactional (4)
    public void deleteById(@NotNull Long id) {
        findById(id).ifPresent(entityManager::remove);
    }

    @ReadOnly (3)
    public List<Genre> findAll(@NotNull SortingAndOrderArguments args) {
        String qlString = "SELECT g FROM Genre as g";
        if (args.getOrder().isPresent() && args.getSort().isPresent() && VALID_PROPERTY_NAMES.contains(args.getSort().get())) {
                qlString += " ORDER BY g." + args.getSort().get() + " " + args.getOrder().get().toLowerCase();
        }
        TypedQuery<Genre> query = entityManager.createQuery(qlString, Genre.class);
        query.setMaxResults(args.getMax().orElseGet(applicationConfiguration::getMax));
        args.getOffset().ifPresent(query::setFirstResult);

        return query.getResultList();
    }

    @Override

    @Transactional (4)
    public int update(@NotNull Long id, @NotBlank String name) {
        return entityManager.createQuery("UPDATE Genre g SET name = :name where id = :id")
                .setParameter("name", name)
                .setParameter("id", id)
                .executeUpdate();
    }

    @Override (4)
    @Transactional (4)
    public Genre saveWithException(@NotBlank String name) {
        save(name);
        throw new PersistenceException();
    }
}

1	Use `javax.inject.Singleton` to designate a class as a singleton.
2	Inject easily an `EntityManager`.
3	All database access needs to be wrapped inside a transaction. As the method only reads data from the database, annotate it with `@ReadOnly`.
4	This method modifies the database, thus it is annoated with `@Transactional`.

4.6. Controller

Micronaut’s validation is built on the standard framework – JSR 380, also known as Bean Validation 2.0.

Hibernate Validator is a reference implementation of the validation API. Starting with Micronaut 1.2, Micronaut has built-in support for validation of beans that are annotated with javax.validation annotations.

The necessary dependencies are included by default when creating a new application, so you don’t need to add anything else.

Create two classes to encapsulate Save and Update operations:

src/main/java/example/micronaut/GenreSaveCommand.java

package example.micronaut;

import io.micronaut.core.annotation.Introspected;

import javax.validation.constraints.NotBlank;

@Introspected (1)
public class GenreSaveCommand {

    @NotBlank
    private String name;

    public GenreSaveCommand() {
    }

    public GenreSaveCommand(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

1	Annotate the class with `@Introspected` to generate the Bean Metainformation at compile time.

src/main/java/example/micronaut/GenreUpdateCommand.java

package example.micronaut;

import io.micronaut.core.annotation.Introspected;

import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;

@Introspected
public class GenreUpdateCommand {
    @NotNull
    private Long id;

    @NotBlank
    private String name;

    public GenreUpdateCommand() {
    }

    public GenreUpdateCommand(Long id, String name) {
        this.id = id;
        this.name = name;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

Create a POJO to encapsulate Sorting and Pagination:

src/main/java/example/micronaut/SortingAndOrderArguments.java

package example.micronaut;

import io.micronaut.core.annotation.Introspected;

import io.micronaut.core.annotation.Nullable;
import javax.validation.constraints.Pattern;
import javax.validation.constraints.Positive;
import javax.validation.constraints.PositiveOrZero;
import java.util.Optional;

@Introspected
public class SortingAndOrderArguments {

    @Nullable
    @PositiveOrZero (1)
    private Integer offset;

    @Nullable
    @Positive (1)
    private Integer max;

    @Nullable
    @Pattern(regexp = "id|name")  (1)
    private String sort;

    @Pattern(regexp = "asc|ASC|desc|DESC")  (1)
    @Nullable
    private String order;

    public SortingAndOrderArguments() {

    }

    public Optional<Integer> getOffset() {
        return Optional.ofNullable(offset);
    }

    public void setOffset(@Nullable Integer offset) {
        this.offset = offset;
    }

    public Optional<Integer> getMax() {
        return Optional.ofNullable(max);
    }

    public void setMax(@Nullable Integer max) {
        this.max = max;
    }

    public Optional<String> getSort() {
        return Optional.ofNullable(sort);
    }

    public void setSort(@Nullable String sort) {
        this.sort = sort;
    }

    public Optional<String> getOrder() {
        return Optional.ofNullable(order);
    }

    public void setOrder(@Nullable String order) {
        this.order = order;
    }
}

1	Use `javax.validation.constraints` Constraints to ensure the incoming data matches your expectations.

Create GenreController, a controller which exposes a resource with the common CRUD operations:

src/main/java/example/micronaut/GenreController.java

package example.micronaut;

import example.micronaut.domain.Genre;
import io.micronaut.http.HttpHeaders;
import io.micronaut.http.HttpResponse;
import io.micronaut.http.annotation.Body;
import io.micronaut.http.annotation.Controller;
import io.micronaut.http.annotation.Delete;
import io.micronaut.http.annotation.Get;
import io.micronaut.http.annotation.Post;
import io.micronaut.http.annotation.Put;
import io.micronaut.scheduling.TaskExecutors;
import io.micronaut.scheduling.annotation.ExecuteOn;

import javax.persistence.PersistenceException;
import javax.validation.Valid;
import java.net.URI;
import java.util.List;

@ExecuteOn(TaskExecutors.IO)  (1)
@Controller("/genres")  (2)
public class GenreController {

    protected final GenreRepository genreRepository;

    public GenreController(GenreRepository genreRepository) { (3)
        this.genreRepository = genreRepository;
    }

    @Get("/{id}") (4)
    public Genre show(Long id) {
        return genreRepository
                .findById(id)
                .orElse(null); (5)
    }

    @Put (6)
    public HttpResponse update(@Body @Valid GenreUpdateCommand command) { (7)
        int numberOfEntitiesUpdated = genreRepository.update(command.getId(), command.getName());

        return HttpResponse
                .noContent()
                .header(HttpHeaders.LOCATION, location(command.getId()).getPath()); (8)
    }

    @Get(value = "/list{?args*}") (9)
    public List<Genre> list(@Valid SortingAndOrderArguments args) {
        return genreRepository.findAll(args);
    }

    @Post (10)
    public HttpResponse<Genre> save(@Body @Valid GenreSaveCommand cmd) {
        Genre genre = genreRepository.save(cmd.getName());

        return HttpResponse
                .created(genre)
                .headers(headers -> headers.location(location(genre.getId())));
    }

    @Post("/ex") (11)
    public HttpResponse<Genre> saveExceptions(@Body @Valid GenreSaveCommand cmd) {
        try {
            Genre genre = genreRepository.saveWithException(cmd.getName());
            return HttpResponse
                    .created(genre)
                    .headers(headers -> headers.location(location(genre.getId())));
        } catch(PersistenceException e) {
            return HttpResponse.noContent();
        }
    }

    @Delete("/{id}") (12)
    public HttpResponse delete(Long id) {
        genreRepository.deleteById(id);
        return HttpResponse.noContent();
    }

    protected URI location(Long id) {
        return URI.create("/genres/" + id);
    }

    protected URI location(Genre genre) {
        return location(genre.getId());
    }
}

1	It is critical that any blocking I/O operations (such as fetching the data from the database) are offloaded to a separate thread pool that does not block the Event loop.
2	The class is defined as a controller with the `@Controller` annotation mapped to the path `/genres`.
3	Constructor injection.
4	Maps a `GET` request to `/genres/{id}` which attempts to show a genre. This illustrates the use of a URL path variable.
5	Returning `null` when the genre doesn’t exist makes Micronaut to response with 404 (not found).
6	Maps a `PUT` request to `/genres` which attempts to update a genre.
7	Add `@Valid` to any method parameter which requires validation. Use a POJO supplied as a JSON payload in the request to populate command.
8	It is easy to add custom headers to the response.
9	Maps a `GET` request to `/genres` which returns a list of genres. This mapping illustrates URL parameters being mapped to a single POJO.
10	Maps a `POST` request to `/genres` which attempts to save a genre.
11	Maps a `POST` request to `/ex` which generates an exception.
12	Maps a `DELETE` request to `/genres/{id}` which attempts to remove a genre. This illustrates the use of a URL path variable.

4.7. Writing Tests

Create a test which verifies the CRUD operations:

src/test/java/example/micronaut/GenreControllerTest.java

package example.micronaut;

import example.micronaut.domain.Genre;
import io.micronaut.core.type.Argument;
import io.micronaut.http.HttpHeaders;
import io.micronaut.http.HttpRequest;
import io.micronaut.http.HttpResponse;
import io.micronaut.http.HttpStatus;
import io.micronaut.http.client.HttpClient;
import io.micronaut.http.client.annotation.Client;
import io.micronaut.http.client.exceptions.HttpClientResponseException;
import io.micronaut.test.extensions.junit5.annotation.MicronautTest;
import org.junit.jupiter.api.Test;

import javax.inject.Inject;
import java.util.ArrayList;
import java.util.List;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNotNull;
import static org.junit.jupiter.api.Assertions.assertThrows;

@MicronautTest (1)
public class GenreControllerTest {

    @Inject
    @Client("/")
    HttpClient client; (2)

    @Test
    public void supplyAnInvalidOrderTriggersValidationFailure() {
        HttpClientResponseException thrown = assertThrows(HttpClientResponseException.class, () -> {
            client.toBlocking().exchange(HttpRequest.GET("/genres/list?order=foo"));
        });

        assertNotNull(thrown.getResponse());
        assertEquals(HttpStatus.BAD_REQUEST, thrown.getStatus());
    }

    @Test
    public void testFindNonExistingGenreReturns404() {
        HttpClientResponseException thrown = assertThrows(HttpClientResponseException.class, () -> {
            client.toBlocking().exchange(HttpRequest.GET("/genres/99"));
        });

        assertNotNull(thrown.getResponse());
        assertEquals(HttpStatus.NOT_FOUND, thrown.getStatus());
    }

    @Test
    public void testGenreCrudOperations() {

        List<Long> genreIds = new ArrayList<>();

        HttpRequest request = HttpRequest.POST("/genres", new GenreSaveCommand("DevOps")); (3)
        HttpResponse response = client.toBlocking().exchange(request);
        genreIds.add(entityId(response));

        assertEquals(HttpStatus.CREATED, response.getStatus());

        request = HttpRequest.POST("/genres", new GenreSaveCommand("Microservices")); (3)
        response = client.toBlocking().exchange(request);

        assertEquals(HttpStatus.CREATED, response.getStatus());

        Long id = entityId(response);
        genreIds.add(id);
        request = HttpRequest.GET("/genres/" + id);

        Genre genre = client.toBlocking().retrieve(request, Genre.class); (4)

        assertEquals("Microservices", genre.getName());

        request = HttpRequest.PUT("/genres", new GenreUpdateCommand(id, "Micro-services"));
        response = client.toBlocking().exchange(request);  (5)

        assertEquals(HttpStatus.NO_CONTENT, response.getStatus());

        request = HttpRequest.GET("/genres/" + id);
        genre = client.toBlocking().retrieve(request, Genre.class);
        assertEquals("Micro-services", genre.getName());

        request = HttpRequest.GET("/genres/list");
        List<Genre> genres = client.toBlocking().retrieve(request, Argument.of(List.class, Genre.class));

        assertEquals(2, genres.size());

        request = HttpRequest.POST("/genres/ex", new GenreSaveCommand("Microservices")); (3)
        response = client.toBlocking().exchange(request);

        assertEquals(HttpStatus.NO_CONTENT, response.getStatus());

        request = HttpRequest.GET("/genres/list");
        genres = client.toBlocking().retrieve(request, Argument.of(List.class, Genre.class));

        assertEquals(2, genres.size());

        request = HttpRequest.GET("/genres/list?max=1");
        genres = client.toBlocking().retrieve(request, Argument.of(List.class, Genre.class));

        assertEquals(1, genres.size());
        assertEquals("DevOps", genres.get(0).getName());

        request = HttpRequest.GET("/genres/list?max=1&order=desc&sort=name");
        genres = client.toBlocking().retrieve(request, Argument.of(List.class, Genre.class));

        assertEquals(1, genres.size());
        assertEquals("Micro-services", genres.get(0).getName());

        request = HttpRequest.GET("/genres/list?max=1&offset=10");
        genres = client.toBlocking().retrieve(request, Argument.of(List.class, Genre.class));

        assertEquals(0, genres.size());

        // cleanup:
        for (Long genreId : genreIds) {
            request = HttpRequest.DELETE("/genres/" + genreId);
            response = client.toBlocking().exchange(request);
            assertEquals(HttpStatus.NO_CONTENT, response.getStatus());
        }
    }

    protected Long entityId(HttpResponse response) {
        String path = "/genres/";
        String value = response.header(HttpHeaders.LOCATION);
        if (value == null) {
            return null;
        }
        int index = value.indexOf(path);
        if (index != -1) {
            return Long.valueOf(value.substring(index + path.length()));
        }
        return null;
    }
}

1	Annotate the class with `@MicronautTest` to let Micronaut starts the embedded server and inject the beans. More info: https://micronaut-projects.github.io/micronaut-test/latest/guide/index.html.
2	Inject the `HttpClient` bean in the application context.
3	Creating HTTP Requests is easy thanks to Micronaut’s fluid API.
4	If you care just about the object in the response use `retrieve`.
5	Sometimes, receiving just the object is not enough and you need information about the response. In this case, instead of `retrieve` you should use the `exchange` method.

5. Testing the Application

To run the tests:

$ ./mvnw test

6. Running the Application

To run the application use the ./mvnw mn:run command which will start the application on port 8080.

7. Using Postgresql

When running on production you want to use a real database instead of using H2. Let’s explain how to use Postgres.

After installing Docker, execute the following command to run a postgresql container:

docker run -it --rm \
    -p 5432:5432 \
    -e POSTGRES_USER=dbuser \
    -e POSTGRES_PASSWORD=theSecretPassword \
    -e POSTGRES_DB=micronaut \
    postgres:11.5-alpine

Add Postgresql driver dependency:

pom.xml

<dependency>
    <groupId>org.postgresql</groupId>
    <artifactId>postgresql</artifactId>
    <scope>runtime</scope>
</dependency>

To use postgresql, setup several environment variables which match those defined in application.yml:

$ export JDBC_URL=jdbc:postgresql://localhost:5432/micronaut
$ export JDBC_USER=dbuser
$ export JDBC_PASSWORD=theSecretPassword
$ export JDBC_DRIVER=org.postgresql.Driver

Run the app again. If you take a close look to the output, you can see that the app uses postgresql:

..
...
08:40:02.746 [main] INFO  org.hibernate.dialect.Dialect - HHH000400: Using dialect: org.hibernate.dialect.PostgreSQL10Dialect
....

Connect to your postgresql database, and you will see both genre and book tables.

Save one genre, and your genre table will now contain an entry.

curl -X "POST" "http://localhost:8080/genres" \
     -H 'Content-Type: application/json; charset=utf-8' \
     -d $'{ "name": "music" }'

8. Next steps

Read more about Configurations for Data Access section in the Micronaut documentation.

9. Help with Micronaut

Object Computing, Inc. (OCI) sponsored the creation of this Guide. A variety of consulting and support services are available.

Meet the Team.

Table of Contents

Access a database with JPA and Hibernate

1. Getting Started

2. What you will need

3. Solution

4. Writing the App

4.1. Data Source configuration

4.2. JPA configuration

4.3. Domain

4.4. Application Configuration

4.5. Repository Access

4.6. Controller

4.7. Writing Tests

5. Testing the Application

6. Running the Application

7. Using Postgresql

8. Next steps

9. Help with Micronaut