Implementasi microservice dengan Java EE pada KumuluzEE

Melanjutkan blog sebelumnya, kali ini kita akan membuat REST API menggunakan standar Java EE pada framework KumuluzEE.

1. Tambahkan modul jax-rs untuk membuat REST

<dependency>
    <groupId>com.kumuluz.ee</groupId>
    <artifactId>kumuluzee-jax-rs</artifactId>
    <version>${kumuluzee.version}</version>
</dependency>

2. Tambahkan modul cdi untuk context dependency injection

<dependency>
    <groupId>com.kumuluz.ee</groupId>
    <artifactId>kumuluzee-cdi</artifactId>
    <version>${kumuluzee.version}</version>
</dependency>

3. Tambahkan modul jpa untuk ORM ke database

<dependency>
    <groupId>com.kumuluz.ee</groupId>
    <artifactId>kumuluzee-jpa</artifactId>
    <version>${kumuluzee.version}</version>
</dependency>

4. Tambahkan library HSQLDB untuk database

<dependency>
    <groupId>org.hsqldb</groupId>
    <artifactId>hsqldb</artifactId>
    <version>2.3.2</version>
</dependency>

5. Tambahkan library Lombok

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.16.6</version>
</dependency>

6. Tambahkan directory META-INF pada directory resources, dan buat file persistence.xml

<?xml version="1.0" encoding="UTF-8" ?>

<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
             http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
             version="2.1">

    <persistence-unit name="schools" transaction-type="RESOURCE_LOCAL">

        <class>org.nostra.kumuluz.models.Students</class>

        <properties>
            <property name="javax.persistence.jdbc.driver" value="org.hsqldb.jdbcDriver" />
            <property name="javax.persistence.jdbc.url"
                      value="jdbc:hsqldb:mem:unit-testing-jpa:9001:blog" />
            <property name="javax.persistence.jdbc.user" value="sa" />
            <property name="javax.persistence.jdbc.password" value="" />

            <property name="javax.persistence.schema-generation.database.action" value="create"/>
            <property name="javax.persistence.schema-generation.create-source" value="metadata"/>
            <property name="javax.persistence.schema-generation.drop-source" value="metadata"/>
        </properties>

    </persistence-unit>
</persistence>

7. Buat domain model Students

@Data
@Entity
@NamedQuery(name="Students.findAll", query="SELECT s FROM Students s")
public class Students {

    @Id
    private String id;

    private String firstName;

    private String lastName;

    private Date dob;

    @PrePersist
    public void prePersist(){
        id = UUID.randomUUID().toString();
    }
}

8. Ubah main class App menjadi seperti dibawah ini

@ApplicationPath("/v1/")
public class App extends javax.ws.rs.core.Application {
}

9. Buat resource (REST) API untuk Students

@Path("/students")
@Produces(MediaType.APPLICATION_JSON)
@Consumes(MediaType.APPLICATION_JSON)
@RequestScoped
public class StudentsResource {

    @PersistenceContext(unitName = "schools")
    private EntityManager em;

    @GET
    public Response getStudents() {

        TypedQuery query = em.createNamedQuery("Students.findAll", Students.class);

        List studentses = query.getResultList();

        return Response.ok(studentses).build();
    }

    @GET
    @Path("/{id}")
    public Response getStudents(@PathParam("id") String id) {

        Students b = em.find(Students.class, id);

        return Response.ok(b).build();
    }

    @POST
    public Response createStudents(Students b) {

        b.setId(null);

        em.getTransaction().begin();

        em.persist(b);

        em.getTransaction().commit();

        return Response.status(Response.Status.CREATED).entity(b).build();
    }
}

10. Buat file beans.xml pada directory META-INF untuk mengaktifkan context dependency injection

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="
  http://xmlns.jcp.org/xml/ns/javaee
  http://xmlns.jcp.org/xml/ns/javaee/beans_1_2.xsd"
       bean-discovery-mode="annotated">

</beans>

11. Kemudian build menggunakan perintah Maven

mvn clean package

12. Jalankan aplikasi dengan perintah :

java -cp target/classes:target/dependency/* com.kumuluz.ee.EeApplication

Test REST API dengan cara :

1. Call Http POST method ke http://localhost:8080/v1/students untuk insert data ke database

curl -X POST 'http://localhost:8080/v1/students' \
-H 'Content-Type:application/json' \
-d '{"firstName":"agus","lastName":"winarno","dob":"1984-08-17"}'

{
"id":"c8fe9c5f-3004-419d-b457-706f2ff02ac9",
"firstName":"agus",
"lastName":"winarno",
"dob":461548800000
}

2. Call Http GET method atau Buka browser dengan url http://localhost:8080/v1/students

3. Call Http GET method atau Buka browser dengan url http://localhost:8080/v1/students/{id}

Sekarang kita sudah dapat membuat microservice dengan Java EE API, semoga bermanfaat :)
Bitbucket link :

• https://agus3winarno@bitbucket.org/agus3winarno/kumuluz-sample.git

Referensi :

• https://blog.kumuluz.com/architecture/2015/06/04/microservices-with-java-ee-and-kumuluzee.html