问题
I'm developing a Java desktop application and was really interested in use JavaFX. I'm planning to use an MVC architecture because I have had some experience with Java EE and the MVC model.
I want to store data in a embedded derby database and use Hibernate as persistence layer but I can't find a great tutorial about implementing MVC with hibernate and JavaFX.
I have created the persistence file but I am not sure how to make it work with JavaFX. In Java EE I inject EJB services or DAOs but since my app is not server connected I think I can't do that.
Can someone explain me how to achieve that? It is possible to use them together?
回答1:
In one of my last JavaFX Projects, I created under my Service Layer a DataBroker class, which could do all the CRUD Operations on the Database.
Example:
public class DataBroker {
private EntityManager em;
public DataBroker() {
init();
}
private void init() {
this.em = Persistence.createEntityManagerFactory("<NAME_OF_YOUR_PU>").createEntityManager();
}
public Person saveOrUpdate(Person entity) {
em.getTransaction().begin();
T savedEntity = em.merge(entity);
em.getTransaction().commit();
return savedEntity;
}
public List<Person> getAllPersons() {
TypedQuery<Person> query = em.createNamedQuery(Person.GET_ALL, Person.class);
return query.getResultList();
}
}
If you only need one DataBroker Instance, you maybe can realize it as a Singleton, if you need a Pool of Instances, create a Pool. This is the advantage of a Application Server, he does this all for you and you only have to annotate your Classes or Members.
I hope this will help you.
EDIT / UPDATE Here is a working example with EclipseLink 2.1, but it is only the Persistence Provider, so it works also with Hibernate.
I created a DataBroker like in the above example which implements my IDataBroker Interface and overrides the methods.
IDataBroker
import de.professional_webworkx.crm.domain.Person;
import java.util.List;
public interface IDateBroker {
public abstract void saveOrUpdate(Person person);
public abstract List<Person> getAllPersons();
public abstract Person getPersonById(int id);
public abstract Person getPersonByEmail(String email);
}
DataBroker - not every method is implemented...
import de.professional_webworkx.crm.domain.Person;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.Persistence;
/**
*
* @author Patrick Ott <Patrick.Ott@professional-webworkx.de>
* @version 1.0
*/
public class DataBroker implements IDateBroker {
private EntityManager em;
public DataBroker() {
em = Persistence.createEntityManagerFactory("CRMPU").createEntityManager();
}
@Override
public void saveOrUpdate(Person person) {
em.getTransaction().begin();
em.merge(person);
em.getTransaction().commit();
}
@Override
public List<Person> getAllPersons() {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
@Override
public Person getPersonById(int id) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
@Override
public Person getPersonByEmail(String email) {
throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
}
}
IPersonService Interface
import de.professional_webworkx.crm.domain.Person;
import java.util.List;
public interface IPersonService {
void saveOrUpdate(Person person);
List<Person> getAllPersons();
Person getPersonById(int id);
Person getPersonByEmail(String email);
}
PersonService
import de.professional_webworkx.crm.databroker.DataBroker;
import de.professional_webworkx.crm.databroker.IDateBroker;
import de.professional_webworkx.crm.domain.Person;
import java.util.List;
public class PersonService implements IPersonService {
private IDateBroker broker;
public PersonService() {
broker = new DataBroker();
}
@Override
public void saveOrUpdate(Person person) {
broker.saveOrUpdate(person);
}
@Override
public List<Person> getAllPersons() {
return broker.getAllPersons();
}
@Override
public Person getPersonById(int id) {
return broker.getPersonById(id);
}
@Override
public Person getPersonByEmail(String email) {
return broker.getPersonByEmail(email);
}
}
Our Domain class Person
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
@Entity
@Table(name = "person")
public class Person implements Serializable {
private long id;
private String firstName;
private String lastName;
private String eMail;
public Person() {
}
public Person(String firstName, String lastName, String eMail) {
this.firstName = firstName;
this.lastName = lastName;
this.eMail = eMail;
}
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
public long getId() {
return id;
}
public void setId(long id) {
this.id = id;
}
@Size(min = 2, max = 255, message = "Enter between 2 and 255 characters!")
@Column(name = "firstname")
@NotNull
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
@Column(name = "lastname")
@NotNull
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
@NotNull
public String geteMail() {
return eMail;
}
public void seteMail(String eMail) {
this.eMail = eMail;
}
}
The FXMLController class
import de.professional_webworkx.crm.business.IPersonService;
import de.professional_webworkx.crm.business.PersonService;
import de.professional_webworkx.crm.domain.Person;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Label;
public class FXMLController implements Initializable {
private IPersonService service;
@FXML
private Label label;
@FXML
private void handleButtonAction(ActionEvent event) {
Person p = new Person("Demo", "User", "demo@example.com");
service.saveOrUpdate(p);
}
@Override
public void initialize(URL url, ResourceBundle rb) {
// get an instance of PersonService
service = new PersonService();
}
}
And last but not least the MainApp to start the Application.
import javafx.application.Application;
import static javafx.application.Application.launch;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;
public class MainApp extends Application {
@Override
public void start(Stage stage) throws Exception {
Parent root = FXMLLoader.load(getClass().getResource("/fxml/Scene.fxml"));
Scene scene = new Scene(root);
scene.getStylesheets().add("/styles/Styles.css");
stage.setTitle("JavaFX and Maven");
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch(args);
}
}
This is a standard Maven JavaFX Project created with Netbeans 8. If necessary I can upload the Sources to GitHub or something..
The Database Table will be created with the first commit, because i set up in the persistence.xml file, that Schema Generation as you can see from the file
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.1" 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">
<persistence-unit name="CRMPU" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<class>de.professional_webworkx.crm.domain.Person</class>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/exampleDb?zeroDateTimeBehavior=convertToNull"/>
<property name="javax.persistence.jdbc.user" value="user"/>
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
<property name="javax.persistence.jdbc.password" value="pass"/>
<property name="javax.persistence.schema-generation.database.action" value="create"/>
</properties>
</persistence-unit>
</persistence>
So I hope this will help you to create your project.
Patrick
来源：https://stackoverflow.com/questions/24810254/javafx-hibernatejpa-persistence-derby-db