为什么我的SQL无法与我的Java GUI连接？

Question

遵循了有关dbms连接的视频教程，但该教程无法运行。

试图更改文件路径和Java版本

问题是我还有另一个JDBC项目，该项目工作正常，但很难将其连接到GUI

package sample;

import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.stage.Stage;

public class Main extends Application {

    @Override
    public void start(Stage stage) throws Exception {
        Parent root = FXMLLoader.load(getClass().getResource("calculator.fxml"));
        Scene scene = new Scene(root);
        stage.setScene(scene);
        stage.show();
    }

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

从Scenebuilder分配变量

package sample;

public class ModelTable
{
   String date, voltage, power, efficiency;

   public ModelTable(String date, String voltage, String power,
         String efficiency)
   {
      this.date = date;
      this.voltage = voltage;
      this.power = power;
      this.efficiency = efficiency;
   }

   public String getDate()
   {
      return date;
   }

   public void setDate(String date)
   {
      this.date = date;
   }

   public String getVoltage()
   {
      return voltage;
   }

   public void setVoltage(String voltage)
   {
      this.voltage = voltage;
   }

   public String getPower()
   {
      return power;
   }

   public void setPower(String power)
   {
      this.power = power;
   }

   public String getEfficiency()
   {
      return efficiency;
   }

   public void setEfficiency(String efficiency)
   {
      this.efficiency = efficiency;
   }
}

应该显示sql的表的控制器

package sample;

import java.net.URL;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ResourceBundle;
import java.util.logging.Level;

import com.sun.istack.internal.logging.Logger;

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



public class TableController implements Initializable
{

   @FXML
   private TableView<ModelTable> table;
   @FXML
   private TableColumn<ModelTable, String> col_Date;
   @FXML
   private TableColumn<ModelTable, String> col_Voltage;
   @FXML
   private TableColumn<ModelTable, String> col_Power;
   @FXML
   private TableColumn<ModelTable, String> col_Efficiency;

   ObservableList<ModelTable> oblist = FXCollections.observableArrayList();


   @Override
   public void initialize(URL location, ResourceBundle resources) {

      try {
         Connection con = DBConnector.getConnection();

         ResultSet rs = con.createStatement().executeQuery("select * from readings");

         while (rs.next()) {
            oblist.add(new ModelTable(rs.getString("datetime"), rs.getString("voltageread"), rs.getString("powerread"), rs.getString("efficiency")));
         }
      }
      catch (SQLException ex)
      {
         Logger.getLogger(TableController.class.getName(), null).log(Level.SEVERE, null, ex);
      }


      col_Date.setCellValueFactory(new PropertyValueFactory<>("Date"));
      col_Voltage.setCellValueFactory(new PropertyValueFactory<>("Voltage"));
      col_Power.setCellValueFactory(new PropertyValueFactory<>("Power"));
      col_Efficiency.setCellValueFactory(new PropertyValueFactory<>("Efficiency"));

      table.setItems(oblist);
   }

}

数据库连接

package sample;

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

public class DBConnector
{
   public static Connection getConnection() throws SQLException {
      Connection connection = DriverManager.getConnection("jdbc:postgresql://localhost:5432/SemesterProject4", "postgres", "******");

      return connection;
   }
}

在Scenebuilder中创建的FXML文件

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

<?import javafx.scene.control.DatePicker?>
<?import javafx.scene.control.TableColumn?>
<?import javafx.scene.control.TableView?>
<?import javafx.scene.image.Image?>
<?import javafx.scene.image.ImageView?>
<?import javafx.scene.layout.AnchorPane?>


<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity"
    minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0"
    prefWidth="600.0" stylesheets="@style.css"
    xmlns="http://javafx.com/javafx"
    xmlns:fx="http://javafx.com/fxml"
    fx:controller="sample.TableController">
    <children>
        <ImageView layoutX="-41.0" layoutY="-29.0"
            pickOnBounds="true" preserveRatio="true">
            <image>
                <Image
                    url="@../../../Java/src/GUI/Images/160928151119_1_900x600.jpg" />
            </image>
        </ImageView>
        <DatePicker layoutX="14.0" layoutY="13.0" prefHeight="36.0"
            prefWidth="251.0" AnchorPane.leftAnchor="10.0" />
        <DatePicker layoutX="335.0" layoutY="13.0"
            prefHeight="36.0" prefWidth="251.0" AnchorPane.rightAnchor="10.0" />
        <TableView fx:id="table" layoutX="192.0" layoutY="112.0"
            prefHeight="200.0" prefWidth="200.0" AnchorPane.bottomAnchor="10.0"
            AnchorPane.leftAnchor="10.0" AnchorPane.rightAnchor="10.0"
            AnchorPane.topAnchor="60.0">
            <columns>
                <TableColumn fx:id="col_Date" prefWidth="75.0"
                    text="Date" />
                <TableColumn fx:id="col_Voltage" prefWidth="75.0"
                    text="Voltage" />
                <TableColumn fx:id="col_Power" prefWidth="75.0"
                    text="Power" />
                <TableColumn fx:id="col_Efficiency" prefWidth="75.0"
                    text="Efficiency" />
            </columns>
        </TableView>
    </children>
</AnchorPane>

错误消息

Exception in Application start method
java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at com.sun.javafx.application.LauncherImpl.launchApplicationWithArgs(LauncherImpl.java:389)
    at com.sun.javafx.application.LauncherImpl.launchApplication(LauncherImpl.java:328)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at sun.launcher.LauncherHelper$FXHelper.main(Unknown Source)
Caused by: java.lang.RuntimeException: Exception in Application start method
    at com.sun.javafx.application.LauncherImpl.launchApplication1(LauncherImpl.java:917)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication$154(LauncherImpl.java:182)
    at java.lang.Thread.run(Unknown Source)
Caused by: javafx.fxml.LoadException: 
/C:/Users/Bragi/OneDrive%20-%20ViaUC/GBE%20VIA/Semester%204/SEP4%20Semester%20Project/DataBaseConnection/bin/sample/calculator.fxml

    at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2579)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
    at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
    at sample.Main.start(Main.java:13)
    at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$161(LauncherImpl.java:863)
    at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$174(PlatformImpl.java:326)
    at com.sun.javafx.application.PlatformImpl.lambda$null$172(PlatformImpl.java:295)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.application.PlatformImpl.lambda$runLater$173(PlatformImpl.java:294)
    at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$147(WinApplication.java:177)
    ... 1 more
Caused by: java.lang.NullPointerException
    at com.sun.istack.internal.logging.Logger.getLogger(Unknown Source)
    at sample.TableController.initialize(TableController.java:54)
    at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
    ... 17 more
Exception running application sample.Main