JavaFX MySQL-forbindelseseksempel tak

Som minimum har du brug for tre klasser:en til at repræsentere dine data, en til din brugergrænseflade og en til at administrere databaseforbindelsen. I en rigtig app har du selvfølgelig brug for mere end dette. Dette eksempel følger det samme grundlæggende eksempel som TableView tutorial

Antag, at din database har en person tabel med tre kolonner, first_name , last_name , email_address .

Så ville du skrive en Person klasse:

import javafx.beans.property.StringProperty ;
import javafx.beans.property.SimpleStringProperty ;

public class Person {
    private final StringProperty firstName = new SimpleStringProperty(this, "firstName");
    public StringProperty firstNameProperty() {
        return firstName ;
    }
    public final String getFirstName() {
        return firstNameProperty().get();
    }
    public final void setFirstName(String firstName) {
        firstNameProperty().set(firstName);
    }

    private final StringProperty lastName = new SimpleStringProperty(this, "lastName");
    public StringProperty lastNameProperty() {
        return lastName ;
    }
    public final String getLastName() {
        return lastNameProperty().get();
    }
    public final void setLastName(String lastName) {
        lastNameProperty().set(lastName);
    }

    private final StringProperty email = new SimpleStringProperty(this, "email");
    public StringProperty emailProperty() {
        return email ;
    }
    public final String getEmail() {
        return emailProperty().get();
    }
    public final void setEmail(String email) {
        emailProperty().set(email);
    }

    public Person() {}

    public Person(String firstName, String lastName, String email) {
        setFirstName(firstName);
        setLastName(lastName);
        setEmail(email);
    }

}

En klasse til at få adgang til data fra databasen:

import java.sql.Connection ;
import java.sql.DriverManager ;
import java.sql.SQLException ;
import java.sql.Statement ;
import java.sql.ResultSet ;

import java.util.List ;
import java.util.ArrayList ;

public class PersonDataAccessor {

    // in real life, use a connection pool....
    private Connection connection ;

    public PersonDataAccessor(String driverClassName, String dbURL, String user, String password) throws SQLException, ClassNotFoundException {
        Class.forName(driverClassName);
        connection = DriverManager.getConnection(dbURL, user, password);
    }

    public void shutdown() throws SQLException {
        if (connection != null) {
            connection.close();
        }
    }

    public List<Person> getPersonList() throws SQLException {
        try (
            Statement stmnt = connection.createStatement();
            ResultSet rs = stmnt.executeQuery("select * from person");
        ){
            List<Person> personList = new ArrayList<>();
            while (rs.next()) {
                String firstName = rs.getString("first_name");
                String lastName = rs.getString("last_name");
                String email = rs.getString("email_address");
                Person person = new Person(firstName, lastName, email);
                personList.add(person);
            }
            return personList ;
        } 
    }

    // other methods, eg. addPerson(...) etc
}

Og så en UI-klasse:

import javafx.application.Application ;
import javafx.scene.control.TableView ;
import javafx.scene.control.TableColumn ;
import javafx.scene.control.cell.PropertyValueFactory ;
import javafx.scene.layout.BorderPane ;
import javafx.scene.Scene ;
import javafx.stage.Stage ;

public class PersonTableApp extends Application {
    private PersonDataAccessor dataAccessor ;

    @Override
    public void start(Stage primaryStage) throws Exception {
        dataAccessor = new PersonDataAccessor(...); // provide driverName, dbURL, user, password...

        TableView<Person> personTable = new TableView<>();
        TableColumn<Person, String> firstNameCol = new TableColumn<>("First Name");
        firstNameCol.setCellValueFactory(new PropertyValueFactory<>("firstName"));
        TableColumn<Person, String> lastNameCol = new TableColumn<>("Last Name");
        lastNameCol.setCellValueFactory(new PropertyValueFactory<>("lastName"));
        TableColumn<Person, String> emailCol = new TableColumn<>("Email");
        emailCol.setCellValueFactory(new PropertyValueFactory<>("email"));

        personTable.getColumns().addAll(firstNameCol, lastNameCol, emailCol);

        personTable.getItems().addAll(dataAccessor.getPersonList());

        BorderPane root = new BorderPane();
        root.setCenter(personTable);
        Scene scene = new Scene(root, 600, 400);
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    @Override
    public void stop() throws Exception {
        if (dataAccessor != null) {
            dataAccessor.shutdown();
        }
    }

    public static void main(String[] args) {
        launch(args);
    }
}

(Jeg har lige indtastet det uden at teste, så der kan være slåfejl, manglende import osv., men det burde være nok til at give dig ideen.)