JavaFX：IntelliJ IDEA 工件抛出 NullPointerException
JavaFX: IntelliJ IDEA Artifacts throws NullPointerException
我正在处理 JavaFX 项目。该程序在 运行 通过 IntelliJ IDEA 时按预期工作。然而，当我创建一个工件和 运行 jar 文件时，我得到了登录屏幕，但是当我点击登录按钮时，应用程序崩溃并抛出错误。
我以某种方式通过终端跟踪了错误。
我的代码如下
Main.java :
package application;
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 primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("/FXML/Login.fxml"));
primaryStage.setTitle("Pelican Tours - Login");
primaryStage.setScene(new Scene(root, 311, 429));
primaryStage.show();
primaryStage.setResizable(false);
}
public static void main(String[] args) {
launch(args);
}
}
这会调用 Login.fxml，然后调用 LoginController.java：
package Controllers;
import DBConnection.DBHandler;
import application.Main;
import com.jfoenix.controls.JFXButton;
import com.jfoenix.controls.JFXPasswordField;
import com.jfoenix.controls.JFXTextField;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.stage.Stage;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.io.IOException;
import java.net.URL;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ResourceBundle;
public class LoginController implements Initializable {
@FXML
private JFXTextField username;
@FXML
private JFXPasswordField password;
@FXML
private JFXButton login;
private Connection conn;
private DBHandler handler;
private PreparedStatement pst;
@Override
public void initialize(URL location, ResourceBundle resources) {
handler = new DBHandler();
username.setStyle("-fx-text-inner-color:#a0a2ab;");
password.setStyle("-fx-text-inner-color:#a0a2ab;");
}
@FXML
public void logon() {
conn = handler.getConnection();
String query1 = "SELECT * FROM USER WHERE USERNAME=? AND PASSWORD=?";
try{
pst = conn.prepareStatement(query1);
pst.setString(1,username.getText());
pst.setString(2,password.getText());
ResultSet rs = pst.executeQuery();
//Validate resultset
int count = 0;
while(rs.next()){
count++;
}
if(count==1){
System.out.println("Login Successful!");
login.getScene().getWindow().hide();
Stage dashboard = new Stage();
try{
Parent root = FXMLLoader.load(getClass().getResource("/FXML/Dashboard.fxml"));
Scene scene = new Scene(root);
dashboard.setScene(scene);
dashboard.show();
dashboard.setResizable(false);
}catch(Exception e){
System.out.println("Error loading dashboard!");
System.out.println(e);
e.printStackTrace();
}
}else{
Alert alert = new Alert(Alert.AlertType.ERROR);
alert.setHeaderText("Login Failed!");
alert.setContentText("Invalid Username & Password Combination!");
alert.show();
}
}catch(SQLException e){
e.printStackTrace();
}finally{
try{
handler.closeConnection();
}catch(SQLException e){
e.printStackTrace();
}
}
}
}
当调用 "logon" 操作时，它应该加载仪表板。但是，应用程序崩溃了。
我首先打印了异常，然后打印了它的堆栈跟踪。 :
Connected!
Login Successful!
Error loading dashboard!
java.lang.NullPointerException: Location is required.
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 Controllers.LoginController.logon(LoginController.java:75)
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$MethodHandler.invoke(FXMLLoader.java:1771)
at javafx.fxml.FXMLLoader$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.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase.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$MouseHandler.access00(Scene.java:3485)
at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
at javafx.scene.Scene$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$handleMouseEvent4(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)
据我了解，"java.lang.NullPointerException: Location is required." 是由于 .getResource().
中的路径错误引起的
但是，我在上面发布的 Main.java class 中的相同路径格式有效。 （这就是我获得登录屏幕的方式）。
文件夹结构如下：
Folder Structure
**请注意：**该程序在 IDE 中运行完美。此错误仅在 运行 .jar 文件时发生。
提前致谢！
是的。它的发生是因为路径是错误的。尝试使用 winrar 或类似软件打开 jar 文件。然后尝试找到您尝试在 getResource 中传递的文件。然后尝试将该路径放入 jar 中，并在编译
后再次检查 运行 jar
谢谢。我设法通过将整个项目文件夹设为 "Source Root" 来解决它。 （右键单击项目 --> 将目录标记为 --> Source Root）
我正在处理 JavaFX 项目。该程序在 运行 通过 IntelliJ IDEA 时按预期工作。然而，当我创建一个工件和 运行 jar 文件时，我得到了登录屏幕，但是当我点击登录按钮时，应用程序崩溃并抛出错误。
我以某种方式通过终端跟踪了错误。
我的代码如下
Main.java :
package application;
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 primaryStage) throws Exception{
Parent root = FXMLLoader.load(getClass().getResource("/FXML/Login.fxml"));
primaryStage.setTitle("Pelican Tours - Login");
primaryStage.setScene(new Scene(root, 311, 429));
primaryStage.show();
primaryStage.setResizable(false);
}
public static void main(String[] args) {
launch(args);
}
}
这会调用 Login.fxml，然后调用 LoginController.java：
package Controllers;
import DBConnection.DBHandler;
import application.Main;
import com.jfoenix.controls.JFXButton;
import com.jfoenix.controls.JFXPasswordField;
import com.jfoenix.controls.JFXTextField;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.fxml.Initializable;
import javafx.scene.Parent;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.stage.Stage;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.io.IOException;
import java.net.URL;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ResourceBundle;
public class LoginController implements Initializable {
@FXML
private JFXTextField username;
@FXML
private JFXPasswordField password;
@FXML
private JFXButton login;
private Connection conn;
private DBHandler handler;
private PreparedStatement pst;
@Override
public void initialize(URL location, ResourceBundle resources) {
handler = new DBHandler();
username.setStyle("-fx-text-inner-color:#a0a2ab;");
password.setStyle("-fx-text-inner-color:#a0a2ab;");
}
@FXML
public void logon() {
conn = handler.getConnection();
String query1 = "SELECT * FROM USER WHERE USERNAME=? AND PASSWORD=?";
try{
pst = conn.prepareStatement(query1);
pst.setString(1,username.getText());
pst.setString(2,password.getText());
ResultSet rs = pst.executeQuery();
//Validate resultset
int count = 0;
while(rs.next()){
count++;
}
if(count==1){
System.out.println("Login Successful!");
login.getScene().getWindow().hide();
Stage dashboard = new Stage();
try{
Parent root = FXMLLoader.load(getClass().getResource("/FXML/Dashboard.fxml"));
Scene scene = new Scene(root);
dashboard.setScene(scene);
dashboard.show();
dashboard.setResizable(false);
}catch(Exception e){
System.out.println("Error loading dashboard!");
System.out.println(e);
e.printStackTrace();
}
}else{
Alert alert = new Alert(Alert.AlertType.ERROR);
alert.setHeaderText("Login Failed!");
alert.setContentText("Invalid Username & Password Combination!");
alert.show();
}
}catch(SQLException e){
e.printStackTrace();
}finally{
try{
handler.closeConnection();
}catch(SQLException e){
e.printStackTrace();
}
}
}
}
当调用 "logon" 操作时，它应该加载仪表板。但是，应用程序崩溃了。
我首先打印了异常，然后打印了它的堆栈跟踪。 :
Connected!
Login Successful!
Error loading dashboard!
java.lang.NullPointerException: Location is required.
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 Controllers.LoginController.logon(LoginController.java:75)
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:1771)
at javafx.fxml.FXMLLoader$ControllerMethodEventHandler.handle(FXMLLoader.java:1657)
at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
at javafx.event.Event.fireEvent(Event.java:198)
at javafx.scene.Node.fireEvent(Node.java:8413)
at javafx.scene.control.Button.fire(Button.java:185)
at com.sun.javafx.scene.control.behavior.ButtonBehavior.mouseReleased(ButtonBehavior.java:182)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase.handle(BehaviorSkinBase.java:96)
at com.sun.javafx.scene.control.skin.BehaviorSkinBase.handle(BehaviorSkinBase.java:89)
at com.sun.javafx.event.CompositeEventHandler$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.access00(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$MouseEventNotification.run(GlassViewEventHandler.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent4(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)
据我了解，"java.lang.NullPointerException: Location is required." 是由于 .getResource().
但是，我在上面发布的 Main.java class 中的相同路径格式有效。 （这就是我获得登录屏幕的方式）。
文件夹结构如下：
Folder Structure
**请注意：**该程序在 IDE 中运行完美。此错误仅在 运行 .jar 文件时发生。
提前致谢！
是的。它的发生是因为路径是错误的。尝试使用 winrar 或类似软件打开 jar 文件。然后尝试找到您尝试在 getResource 中传递的文件。然后尝试将该路径放入 jar 中，并在编译
后再次检查 运行 jar谢谢。我设法通过将整个项目文件夹设为 "Source Root" 来解决它。 （右键单击项目 --> 将目录标记为 --> Source Root）