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Исключение при выводе таблицы из базы данных в TableView Java FX

Автор вопроса: Владимир

Решил перенести функционал программы из Java Swing на Java FX. И вот уже несколько дней пытаюсь совершить элементарное действие - вывести данные в TableView. Подскажите, пожалуйста.

Вот такое исключение получаю:

Exception in Application start method
java.lang.reflect.InvocationTargetException
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:464)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:363)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:64)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:564)
    at java.base/sun.launcher.LauncherHelper$FXHelper.main(LauncherHelper.java:1071)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:900)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication$2(LauncherImpl.java:195)
    at java.base/java.lang.Thread.run(Thread.java:832)
Caused by: javafx.fxml.LoadException: 
/D:/1/out/production/1/sample/sample.fxml

    at javafx.fxml/javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2625)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2603)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2466)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3237)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3194)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3163)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3136)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3113)
    at javafx.fxml/javafx.fxml.FXMLLoader.load(FXMLLoader.java:3106)
    at sample.Main.start(Main.java:13)
    at javafx.graphics/com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$9(LauncherImpl.java:846)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runAndWait$12(PlatformImpl.java:455)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$10(PlatformImpl.java:428)
    at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
    at javafx.graphics/com.sun.javafx.application.PlatformImpl.lambda$runLater$11(PlatformImpl.java:427)
    at javafx.graphics/com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:96)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at javafx.graphics/com.sun.glass.ui.win.WinApplication.lambda$runLoop$3(WinApplication.java:174)
    ... 1 more
Caused by: java.lang.NullPointerException: Cannot invoke "javafx.scene.control.TableColumn.setCellValueFactory(javafx.util.Callback)" because "this.meal_id" is null
    at sample.Controller.populateTableView(Controller.java:69)
    at sample.Controller.initialize(Controller.java:49)
    at javafx.fxml/javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2573)
    ... 17 more
Exception running application sample.Main

Process finished with exit code 1

Вот код FXML:

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

<?import javafx.scene.control.TableColumn?>
<?import javafx.scene.control.TableView?>
<?import javafx.scene.layout.AnchorPane?>

<AnchorPane fx:controller="sample.Controller" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="1000.0" prefHeight="800.0" prefWidth="1000.0" style="-fx-pref-width: 1000; -fx-min-width: 1000; -fx-max-width: 1000; -fx-pref-height: 800; -fx-min-height: 800; -fx-max-height: 800;" xmlns="http://javafx.com/javafx/15.0.1" xmlns:fx="http://javafx.com/fxml/1">
   <children>
      <TableView id="main_table" editable="true" fixedCellSize="1.0" layoutX="100.0" layoutY="14.0" prefHeight="200.0" prefWidth="200.0" style="-fx-pref-width: 800;">
        <columns>
          <TableColumn id="meal_id" prefWidth="150.0" text="Ідентифікатор страви" />
            <TableColumn id="meal_name" prefWidth="75.0" text="Назва страви" />
            <TableColumn id="meal_price" prefWidth="75.0" text="Ціна за 1 порцію" />
            <TableColumn id="meal_category" prefWidth="75.0" text="Категорія" />
        </columns>
         <columnResizePolicy>
            <TableView fx:constant="CONSTRAINED_RESIZE_POLICY" />
         </columnResizePolicy>
      </TableView>
   </children>
</AnchorPane>

Это код контролёра:

package sample;
import com.sun.marlin.DDasher;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.control.Alert;
import javafx.scene.control.Alert.AlertType;
import java.net.URL;
import java.util.ResourceBundle;

import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.PropertyValueFactory;

import javafx.scene.control.TableColumn;

import java.sql.*;

public class Controller implements Initializable {
    @FXML
    private URL location;
    @FXML
    private ResourceBundle resources;
    @FXML
    private TableView<MealTableModel> main_table;
    @FXML
    private TableColumn<MealTableModel, Integer> meal_id;

    @FXML
    private TableColumn<MealTableModel, String> meal_name;
    @FXML
    private TableColumn<MealTableModel, Float> meal_price;
    @FXML
    private TableColumn<MealTableModel, String> meal_category;

    private Connection connection;
    private ObservableList<MealTableModel> observableList;
    private ConnectDB connectDB;

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        connectDB = new ConnectDB();
        try {
            populateTableView();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }

    public void populateTableView() throws SQLException {
        observableList = FXCollections.observableArrayList();
        String query ="SELECT * FROM Meals;";
        connection = connectDB.getConnection();
        ResultSet resultSet = connection.createStatement().executeQuery(query);
        while (resultSet.next()) {
            MealTableModel mealTableModel = new MealTableModel();
            mealTableModel.setId(resultSet.getInt("id"));
            mealTableModel.setMealName(resultSet.getString("mealName"));
            mealTableModel.setMealPrice(resultSet.getFloat("MealPrice"));
            mealTableModel.setMealType(resultSet.getString("mealType"));
            observableList.add(mealTableModel);
        }
        meal_id.setCellValueFactory(new PropertyValueFactory<>("id"));
        meal_name.setCellValueFactory(new PropertyValueFactory<>("mealName"));
        meal_price.setCellValueFactory(new PropertyValueFactory<>("mealPrice"));
        meal_category.setCellValueFactory(new PropertyValueFactory<>("mealType"));
        main_table.setItems(observableList);
    }

}

Это код модели:

package sample;

import javafx.beans.property.*;

public class MealTableModel {
    private final IntegerProperty id = new SimpleIntegerProperty();
    private final StringProperty mealName = new SimpleStringProperty();
    private final FloatProperty mealPrice = new SimpleFloatProperty();
    private final StringProperty mealCategory = new SimpleStringProperty();

    public int getId() {
        return id.get();
    }

    public void setId(int value) {
        id.set(value);
    }

    public IntegerProperty idProperty() {
        return id;
    }

    public String getMealName() {
        return mealName.get();
    }

    public void setMealName(String value) {
        mealName.set(value);
    }

    public StringProperty mealNameProperty() {
        return mealName;
    }

    public float getMealPrice() {
        return mealPrice.get();
    }

    public void setMealPrice(float value) {
        mealPrice.set(value);
    }

    public FloatProperty mealPriceProperty() {
        return mealPrice;
    }

    public String getMealType() {
        return mealCategory.get();
    }

    public void setMealType(String value) {
        mealCategory.set(value);
    }

    public StringProperty MealCategoryProperty() {
        return mealCategory;
    }
}

Источник

Ответы (1 шт):

Автор решения: Владимир

Всем спасибо! Проблему решил. Дело было в том, что я не понял, что просто id и fx:id - разные понятия.

Это подключение к базе данных:

package sample;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;

public class ConnectDB {
    protected Connection connection;

    public Connection getConnection() {
        final String connectionString = "jdbc:sqlite:Restaurant.db";
        try {
            Class.forName("org.sqlite.JDBC");
        } catch (ClassNotFoundException e) {
            Logger.getLogger(ConnectDB.class.getName()).log(Level.SEVERE, null, e);
        }
        try {
            connection = DriverManager.getConnection(connectionString);
            System.out.println("OK!");
        } catch (SQLException e) {
            Logger.getLogger(ConnectDB.class.getName()).log(Level.SEVERE, null, e);
        }
        return connection;
    }
}

Это модель таблицы:

package sample;

import javafx.beans.property.*;

public class MealTableModel {
    private SimpleIntegerProperty id = new SimpleIntegerProperty();
    private SimpleStringProperty mealName = new SimpleStringProperty();
    private SimpleFloatProperty mealPrice = new SimpleFloatProperty();
    private SimpleStringProperty mealCategory = new SimpleStringProperty();

    public int getId() {
        return id.get();
    }

    public void setId(int value) {
        id.set(value);
    }

    public IntegerProperty idProperty() {
        return id;
    }

    public String getMealName() {
        return mealName.get();
    }

    public void setMealName(String value) {
        mealName.set(value);
    }

    public StringProperty mealNameProperty() {
        return mealName;
    }

    public float getMealPrice() {
        return mealPrice.get();
    }

    public void setMealPrice(float value) {
        mealPrice.set(value);
    }

    public FloatProperty mealPriceProperty() {
        return mealPrice;
    }

    public String getMealType() {
        return mealCategory.get();
    }

    public void setMealType(String value) {
        mealCategory.set(value);
    }

    public StringProperty MealCategoryProperty() {
        return mealCategory;
    }
}

Это FXML. Как раз здесь была ошибка, о которой писал выше:

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

<?import javafx.scene.control.TableColumn?>
<?import javafx.scene.control.TableView?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.ColumnConstraints?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.layout.RowConstraints?>


<GridPane alignment="center" hgap="10" vgap="10" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/15.0.1" fx:controller="sample.Controller">
   <columnConstraints>
      <ColumnConstraints />
      <ColumnConstraints />
      <ColumnConstraints />
   </columnConstraints>
   <rowConstraints>
      <RowConstraints />
      <RowConstraints />
   </rowConstraints>
   <children>
      <AnchorPane prefHeight="200.0" prefWidth="200.0" style="-fx-max-width: 1000; -fx-min-width: 1000; -fx-pref-width: 1000; -fx-max-height: 800; -fx-min-height: 800; -fx-pref-height: 800;" GridPane.columnIndex="2" GridPane.rowIndex="1">
         <children>
            <TableView fx:id="myTable" id="myTable" layoutX="125.0" layoutY="14.0" prefHeight="200.0" prefWidth="200.0" style="-fx-max-width: 750; -fx-min-width: 750; -fx-pref-width: 750;">
              <columns>
                <TableColumn fx:id="mealID" prefWidth="75.0" text="ідентифікатор страви" />
                <TableColumn fx:id="mealName" prefWidth="75.0" text="Назва страви" />
                  <TableColumn fx:id="mealPrice" prefWidth="75.0" text="Ціна за 1 порцію" />
                  <TableColumn fx:id="mealType" prefWidth="75.0" text="Категорія" />
              </columns>
               <columnResizePolicy>
                  <TableView fx:constant="CONSTRAINED_RESIZE_POLICY" />
               </columnResizePolicy>
            </TableView>
         </children>
      </AnchorPane>
   </children>
</GridPane>

Это контролёр:

package sample;
import com.sun.marlin.DDasher;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.control.Alert;
import javafx.scene.control.Alert.AlertType;
import java.net.URL;
import java.util.ResourceBundle;

import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.TableView;
import javafx.scene.control.cell.PropertyValueFactory;

import javafx.scene.control.TableColumn;

import java.sql.*;

public class Controller implements Initializable {
    @FXML
    private URL location;
    @FXML
    private ResourceBundle resources;
    @FXML
    private TableView<MealTableModel> myTable;
    @FXML
    private TableColumn<MealTableModel, Integer> mealID;

    @FXML
    private TableColumn<MealTableModel, String> mealName;
    @FXML
    private TableColumn<MealTableModel, Float> mealPrice;
    @FXML
    private TableColumn<MealTableModel, String> mealType;

    private Connection connection;
    private ObservableList<MealTableModel> observableList;
    private ConnectDB connectDB;

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        connectDB = new ConnectDB();
        try {
            populateTableView();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }

    public void populateTableView() throws SQLException {
        observableList = FXCollections.observableArrayList();
        String query ="SELECT * FROM Meals;";
        connection = connectDB.getConnection();
        ResultSet resultSet = connection.createStatement().executeQuery(query);
        while (resultSet.next()) {
            MealTableModel mealTableModel = new MealTableModel();
            mealTableModel.setId(resultSet.getInt("id"));
            mealTableModel.setMealName(resultSet.getString("mealName"));
            mealTableModel.setMealPrice(resultSet.getFloat("MealPrice"));
            mealTableModel.setMealType(resultSet.getString("mealType"));
            observableList.add(mealTableModel);
        }
        mealID.setCellValueFactory(new PropertyValueFactory<>("id"));
        mealName.setCellValueFactory(new PropertyValueFactory<>("mealName"));
        mealPrice.setCellValueFactory(new PropertyValueFactory<>("mealPrice"));
        mealType.setCellValueFactory(new PropertyValueFactory<>("mealType"));
        myTable.setItems(observableList);
    }
}
→ Ссылка

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