每當我單擊添加按鈕時，都會出現錯誤。 （Java FX場景構建器和Eclipse）

Question

package application;

import java.net.URL;
import java.util.ResourceBundle;

import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Node;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.stage.Stage;

public class PrinterController implements Initializable {
  @FXML private Button ButtonHome;
  @FXML private TableView < Printer > table;
  @FXML private TableColumn < Printer, String > Make;
  @FXML private TableColumn < Printer, Integer > Model;
  @FXML private TableColumn < Printer, Integer > SerialNO;
  @FXML private TableColumn < Printer, Integer > IP;
  @FXML private TableColumn < Printer, Integer > MAC;
  @FXML private TableColumn < Printer, String > Cartridge;
  @FXML private TableColumn < Printer, String > Date;
  @FXML private TableColumn < Printer, String > Other;
  @FXML private TableColumn < Printer, String > Remarks;
  @FXML private TextField makeInput;
  @FXML private TextField modelInput;
  @FXML private TextField serialInput;
  @FXML private TextField ipInput;
  @FXML private TextField macInput;
  @FXML private TextField cartridgeInput;
  @FXML private TextField dateInput;
  @FXML private TextField otherInput;
  @FXML private TextField remarksInput;
  @FXML private Button done;
  @FXML private Button buttonadd1;


  //Executing Home Button

  public ObservableList < Printer > list = FXCollections.observableArrayList(
    new Printer("HP", 230, 001, 192168, 888, "HP", "24", "-", "New")
  );

  public void AddforPrinter(ActionEvent event) throws Exception {
    Stage primaryStage = new Stage();
    Parent root = FXMLLoader.load(getClass().getResource("/application/PrinterAdd.fxml"));
    Scene scene = new Scene(root, 400, 400);
    scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
    primaryStage.setScene(scene);
    primaryStage.show();
    //primaryStage.
  }

  //     public void AddforPrinter(ActionEvent event) throws Exception
  //        {
  //            ((Node)(event.getSource())).getScene().getWindow().hide();
  //            Stage primaryStage=new Stage();
  //            Parent root = FXMLLoader.load(getClass().getResource("/application/PrinterAdd.fxml"));
  //            Scene scene = new Scene(root,500,500);
  //            scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
  //            primaryStage.setScene(scene);
  //            primaryStage.show();    
  //            
  //        }

  public void Home(ActionEvent event) throws Exception {
    ((Node)(event.getSource())).getScene().getWindow().hide();
    Stage primaryStage = new Stage();
    Parent root = FXMLLoader.load(getClass().getResource("/application/Main.fxml"));
    Scene scene = new Scene(root, 448, 388);
    scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
    primaryStage.setScene(scene);
    primaryStage.show();

  }

  //Executing Add Button






  @Override
  public void initialize(URL location, ResourceBundle resources) {
    Make.setCellValueFactory(new PropertyValueFactory < Printer, String > ("Make"));
    Model.setCellValueFactory(new PropertyValueFactory < Printer, Integer > ("Model"));
    SerialNO.setCellValueFactory(new PropertyValueFactory < Printer, Integer > ("SerialNO"));
    IP.setCellValueFactory(new PropertyValueFactory < Printer, Integer > ("IP"));
    MAC.setCellValueFactory(new PropertyValueFactory < Printer, Integer > ("MAC"));
    Cartridge.setCellValueFactory(new PropertyValueFactory < Printer, String > ("Cartridge"));
    Date.setCellValueFactory(new PropertyValueFactory < Printer, String > ("Date"));
    Other.setCellValueFactory(new PropertyValueFactory < Printer, String > ("Other"));
    Remarks.setCellValueFactory(new PropertyValueFactory < Printer, String > ("Remarks"));

    table.setItems(list);


  }

  public void onDone(ActionEvent event) {
    // This code is for supplying the data
    Printer entry = new Printer(makeInput.getText(), Integer.parseInt(modelInput.getText()), Integer.parseInt(serialInput.getText()),
      Integer.parseInt(ipInput.getText()), Integer.parseInt(macInput.getText()), cartridgeInput.getText(), dateInput.getText(),
      otherInput.getText(), remarksInput.getText());

    // This code is for fetching the data

    list.add(entry);

    // This code is for clearing the text fields


  }





}

因此，每當我單擊添加按鈕時，它將引發一個空的ppinter異常。 之前也給過我類似的錯誤，但是我可以通過在父級根目錄中的fxml文件之前提供程序包名稱來解決此錯誤。

package application;

import javafx.beans.property.SimpleIntegerProperty;
import javafx.beans.property.SimpleStringProperty;

public class Printer {
  private final SimpleStringProperty make;
  private final SimpleIntegerProperty model;
  private final SimpleIntegerProperty serialNO;
  private final SimpleIntegerProperty IP;
  private final SimpleIntegerProperty MAC;
  private final SimpleStringProperty Cartridge;
  private final SimpleStringProperty date;
  private final SimpleStringProperty other;
  private final SimpleStringProperty remarks;

  public Printer(String make, Integer model, Integer serialNO, Integer IP, Integer MAC, String cartridge, String date,
    String other, String remarks) {
    super();
    this.make = new SimpleStringProperty(make);
    this.model = new SimpleIntegerProperty(model);
    this.serialNO = new SimpleIntegerProperty(serialNO);
    this.IP = new SimpleIntegerProperty(IP);
    this.MAC = new SimpleIntegerProperty(MAC);
    this.Cartridge = new SimpleStringProperty(cartridge);
    this.date = new SimpleStringProperty(date);
    this.other = new SimpleStringProperty(other);
    this.remarks = new SimpleStringProperty(remarks);
  }

  public String getMake() {
    return make.get();
  }

  public Integer getModel() {
    return model.get();
  }

  public Integer getSerialNO() {
    return serialNO.get();
  }

  public Integer getIP() {
    return IP.get();
  }

  public Integer getMAC() {
    return MAC.get();
  }

  public String getCartridge() {
    return Cartridge.get();
  }

  public String getDate() {
    return date.get();
  }

  public String getOther() {
    return other.get();
  }

  public String getRemarks() {
    return remarks.get();
  }

}

每當我在打印場景上點擊添加時，都會給我錯誤，並且錯誤與運行時間和空點異常有關。 我不知道該怎么解決。 我已經嘗試了很多次，但每次都失敗了

Exception in thread "JavaFX Application Thread"
java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java: 1774)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java: 1657)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java: 86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java: 238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java: 191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java: 59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java: 58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java: 114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java: 56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java: 114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java: 56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java: 114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java: 74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java: 49)
at javafx.event.Event.fireEvent(Event.java: 198)
at javafx.scene.Node.fireEvent(Node.java: 8413)
at javafx.scene.control.Button.fire(Button.java: 185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java: 182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java: 96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase$1.handle(BehaviorSkinBase.java: 89)
at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java: 218)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java: 80)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java: 238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java: 191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java: 59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java: 58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java: 114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java: 56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java: 114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java: 56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java: 114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java: 74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java: 54)
at javafx.event.Event.fireEvent(Event.java: 198)
at javafx.scene.Scene$MouseHandler.process(Scene.java: 3757)
at javafx.scene.Scene$MouseHandler.access$1500(Scene.java: 3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java: 1762)
at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java: 2494)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java: 381)
at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java: 295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java: 417)
at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java: 389)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java: 416)
at com.sun.glass.ui.View.handleMouseEvent(View.java: 555)
at com.sun.glass.ui.View.notifyMouse(View.java: 937)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java: 62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java: 43)
at java.lang.reflect.Method.invoke(Method.java: 498)
at sun.reflect.misc.Trampoline.invoke(MethodUtil.java: 71)
at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java: 43)
at java.lang.reflect.Method.invoke(Method.java: 498)
at sun.reflect.misc.MethodUtil.invoke(MethodUtil.java: 275)
at javafx.fxml.FXMLLoader$MethodHandler.invoke(FXMLLoader.java: 1769)
  ...45 more
Caused by: java.lang.NullPointerException: Location is required.
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java: 3207)
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 application.PrinterController.AddforPrinter(PrinterController.java: 58)
  ...55 more

Answer 1

從中刪除Initializable接口實現並更改方法簽名：

  class YourClass implements Initializable {

          @Override
          public void initialize(URL location, ResourceBundle resources) {
             //your code
             table.setItems(list);

        }

    }

對此

class YourClass {

              @Override
              public void initialize() {
                 //your code
                 table.setItems(list);

            }

        }