Java NoSuchMethodException - class 中确实存在方法
Java NoSuchMethodException - method does exist in class
我正在构建一个 JavaFx 应用程序，我想创建一个方法来接收一个 GridPane 和一个 Node[] 以及添加到窗格中的项目数量。但是，当我调用该方法时，我得到了一个 NoSuchMethodException。
作为测试，我尝试创建一个 private String helloWorld() 的简单方法 return "Hello World";。此方法确实有效，但当我尝试 运行 gridLogin = buildForm(gridLogin, items); 时，我收到 Exception in thread "main" java.lang.NoSuchMethodException 错误。
Application.java
public class DesktopApplication extends Application {
@Override
public void start(Stage primaryStage) {
BuildGraphicalUserInterface ui = new BuildGraphicalUserInterface();
ui.initStage(primaryStage);
}
}
BuildGraphicalUserInterface.java
package com.fenrir.desktop.UserInterface;
import ...;
public class BuildGraphicalUserInterface {
private final String APP_TITLE = "Fenrir Desktop App";
private final String LOGIN_HEADER = "FENRIR secure";
Stage stage;
Scene sceneLogin, sceneMain, sceneRegister;
GridPane gridLogin, gridMain, gridRegister;
long startTime, endTime;
boolean authorized;
Optional<String> result;
public void initStage(Stage primaryStage) {
stage = primaryStage;
// Set global ui options
stage.setTitle(APP_TITLE);
stage.setResizable(false);
// Setup every screen in application
initScenes(stage);
}
private void initScenes(Stage stage) {
startTime = System.nanoTime();
sceneLogin = buildLoginScreen();
endTime = System.nanoTime();
System.out.println("login:\t" + (endTime - startTime));
startTime = System.nanoTime();
sceneMain = buildMainScreen();
endTime = System.nanoTime();
System.out.println("main:\t" + (endTime - startTime));
startTime = System.nanoTime();
sceneRegister = buildRegisterScreen();
endTime = System.nanoTime();
System.out.println("register:\t" + (endTime - startTime));
stage.setScene(sceneLogin);
stage.show();
}
// BUILD OF SCREENS
private Scene buildLoginScreen() {
gridLogin = new GridPane();
gridLogin.setAlignment(Pos.CENTER);
gridLogin.setVgap(10);
gridLogin.setHgap(10);
Text loginTitle = new Text(LOGIN_HEADER);
loginTitle.setFont(Font.font("Tahoma", FontWeight.NORMAL, 20));
Label usernameLabel = new Label("Username:");
final TextField usernameTextField = new TextField();
Label companyLabel = new Label("Company:");
final TextField companyTextField = new TextField();
Button loginButton = new Button("Login");
Hyperlink registerLink = new Hyperlink();
registerLink.setText("Register");
registerLink.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent e) {
stage.setScene(sceneRegister);
}
});
loginButton.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent e) {
UserAuthentication auth = new UserAuthentication(usernameTextField.getText(), companyTextField.getText());
try {
// check if user exists
auth.authenticate();
// show token pop up
promptTokenAlert();
if (result.isPresent()) {
if (auth.verifyToken(result.get())) {
authorized = true;
stage.setScene(sceneMain);
}
else
wrongTokenAlert();
}
} catch (IOException e1) {
userNotFoundAlert();
usernameTextField.setText("");
companyTextField.setText("");
}
}});
Node[] items = new Node[6];
items[0] = loginTitle;
items[1] = usernameLabel;
items[2] = usernameTextField;
items[3] = companyLabel;
items[4] = companyTextField;
items[5] = loginButton;
items[6] = registerLink;
gridLogin = buildForm(gridLogin, items);
sceneLogin = new Scene(gridLogin, 300, 200);
return sceneLogin;
}
private Scene buildMainScreen() {
gridMain = new GridPane();
final Label authorizedLabel = new Label("Authorized!");
Button logoutButton = new Button("Logout");
logoutButton.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent e) {
authorized = false;
stage.setScene(sceneLogin);
}});
gridMain.add(authorizedLabel, 0, 0);
gridMain.add(logoutButton, 0, 1);
sceneMain = new Scene(gridMain, 800, 600);
return sceneMain;
}
private Scene buildRegisterScreen() {
gridRegister = new GridPane();
gridRegister.setAlignment(Pos.CENTER);
gridRegister.setVgap(10);
gridRegister.setHgap(10);
sceneRegister = new Scene(gridRegister, 300, 200);
Label userName = new Label("Username:");
final TextField userTextField = new TextField();
Label company = new Label("Company:");
final TextField companyTextField = new TextField();
Label phoneNumber = new Label("Phone nr.:");
final TextField phoneNumberTextField = new TextField();
Button registerButton = new Button("Register");
Hyperlink returnLabel = new Hyperlink();
returnLabel.setText("Go back");
returnLabel.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent e) {
stage.setScene(sceneLogin);
}
});
registerButton.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent event) {
/**
* register response
* 1 - user already exists
* 2 - incorrect username
* 3 - incorrect phonenumber
* 4 - unknown error
* 0 - success
*/
int registerResponse;
UserRegistration userReg = new UserRegistration(userTextField.getText(), companyTextField.getText(), phoneNumberTextField.getText());
try {
registerResponse = userReg.Register();
} catch (IOException e) {
registerResponse = 4;
e.printStackTrace();
}
if (registerResponse == 0) {
userRegisteredConfirmation();
stage.setScene(sceneLogin);
} else {
userRegistrationErrorAlert(registerResponse);
}
}
});
gridRegister.add(userName, 0, 1);
gridRegister.add(userTextField, 1, 1);
gridRegister.add(company, 0, 2);
gridRegister.add(companyTextField, 1, 2);
gridRegister.add(phoneNumber, 0, 3);
gridRegister.add(phoneNumberTextField, 1, 3);
gridRegister.add(registerButton, 1, 4);
gridRegister.add(returnLabel, 0, 4);
return sceneRegister;
}
/**
* Builds a form with items received (items should be sorted)
* @param grid
* @param items
* @return
*/
private GridPane buildForm(GridPane grid, Node[] items) {
int row = 0;
for (int i = 0; i < items.length; i++) {
grid.add(items[i], i, row);
if (i % 2 == 0)
row++;
}
return grid;
}
// ALERTS
/**
* Alert is shown when service returns no user
* @return
*/
private Alert userNotFoundAlert() {
Alert alert = new Alert(Alert.AlertType.ERROR);
alert.setTitle("FENRIR security");
alert.setHeaderText("Error");
alert.setContentText("User not recognized");
alert.showAndWait();
return alert;
}
/**
* Alert is shown when user should enter token
* @return
*/
private TextInputDialog promptTokenAlert() {
TextInputDialog alert = new TextInputDialog("");
alert.setTitle("FENRIR security");
alert.setHeaderText("Token requested");
result = alert.showAndWait();
return alert;
}
/**
* Alert is shown when entered token is wrong
* @return
*/
private Alert wrongTokenAlert() {
Alert alert = new Alert(Alert.AlertType.ERROR);
alert.setTitle("FENRIR security");
alert.setHeaderText("Token incorrect");
alert.showAndWait();
return alert;
}
/**
* Confirmation is shown when registration is completed
* @return
*/
private Alert userRegisteredConfirmation() {
Alert alert = new Alert(Alert.AlertType.INFORMATION);
alert.setTitle("FENRIR security");
alert.setHeaderText("Success");
alert.setContentText("Registration completed");
alert.showAndWait();
return alert;
}
/**
* Alert is shown when an error occurs during registration
* @param errorCode
* @return
*/
private Alert userRegistrationErrorAlert(int errorCode) {
Alert alert = new Alert(Alert.AlertType.ERROR);
alert.setTitle("FENRIR security");
alert.setHeaderText("Error");
String errorMessage;
switch (errorCode) {
case 1: errorMessage = "User already exists.";
break;
case 2: errorMessage = "Incorrect username. Username should be at least 2 characters.";
break;
case 3: errorMessage = "Incorrect phone number. Should be 8 characters and only numbers.";
break;
default: errorMessage = "Unknown error. Contact administrator.";
}
alert.setContentText(errorMessage);
alert.showAndWait();
return alert;
}
}
堆栈跟踪
Exception in Application start method
Exception in thread "main" java.lang.NoSuchMethodException: com.fenrir.desktop.DesktopApplication.main([Ljava.lang.String;)
at java.lang.Class.getMethod(Class.java:1786)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:125)
Process finished with exit code 1
这将解决您的问题，安装 e(fx)clipse 这个插件用于 eclise 但我不知道用于 intellij，或者为您的应用程序添加 facet 作为 javafx 应用程序，如果您添加 facet 则不需要 main 方法，或者使用像这样
public class DesktopApplication extends Application {
@Override
public void start(Stage primaryStage) {
BuildGraphicalUserInterface ui = new BuildGraphicalUserInterface();
ui.initStage(primaryStage);
}
public static void main(String[] args) {
launch(args);
}
}
我正在构建一个 JavaFx 应用程序，我想创建一个方法来接收一个 GridPane 和一个 Node[] 以及添加到窗格中的项目数量。但是，当我调用该方法时，我得到了一个 NoSuchMethodException。
作为测试，我尝试创建一个 private String helloWorld() 的简单方法 return "Hello World";。此方法确实有效，但当我尝试 运行 gridLogin = buildForm(gridLogin, items); 时，我收到 Exception in thread "main" java.lang.NoSuchMethodException 错误。
Application.java
public class DesktopApplication extends Application {
@Override
public void start(Stage primaryStage) {
BuildGraphicalUserInterface ui = new BuildGraphicalUserInterface();
ui.initStage(primaryStage);
}
}
BuildGraphicalUserInterface.java
package com.fenrir.desktop.UserInterface;
import ...;
public class BuildGraphicalUserInterface {
private final String APP_TITLE = "Fenrir Desktop App";
private final String LOGIN_HEADER = "FENRIR secure";
Stage stage;
Scene sceneLogin, sceneMain, sceneRegister;
GridPane gridLogin, gridMain, gridRegister;
long startTime, endTime;
boolean authorized;
Optional<String> result;
public void initStage(Stage primaryStage) {
stage = primaryStage;
// Set global ui options
stage.setTitle(APP_TITLE);
stage.setResizable(false);
// Setup every screen in application
initScenes(stage);
}
private void initScenes(Stage stage) {
startTime = System.nanoTime();
sceneLogin = buildLoginScreen();
endTime = System.nanoTime();
System.out.println("login:\t" + (endTime - startTime));
startTime = System.nanoTime();
sceneMain = buildMainScreen();
endTime = System.nanoTime();
System.out.println("main:\t" + (endTime - startTime));
startTime = System.nanoTime();
sceneRegister = buildRegisterScreen();
endTime = System.nanoTime();
System.out.println("register:\t" + (endTime - startTime));
stage.setScene(sceneLogin);
stage.show();
}
// BUILD OF SCREENS
private Scene buildLoginScreen() {
gridLogin = new GridPane();
gridLogin.setAlignment(Pos.CENTER);
gridLogin.setVgap(10);
gridLogin.setHgap(10);
Text loginTitle = new Text(LOGIN_HEADER);
loginTitle.setFont(Font.font("Tahoma", FontWeight.NORMAL, 20));
Label usernameLabel = new Label("Username:");
final TextField usernameTextField = new TextField();
Label companyLabel = new Label("Company:");
final TextField companyTextField = new TextField();
Button loginButton = new Button("Login");
Hyperlink registerLink = new Hyperlink();
registerLink.setText("Register");
registerLink.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent e) {
stage.setScene(sceneRegister);
}
});
loginButton.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent e) {
UserAuthentication auth = new UserAuthentication(usernameTextField.getText(), companyTextField.getText());
try {
// check if user exists
auth.authenticate();
// show token pop up
promptTokenAlert();
if (result.isPresent()) {
if (auth.verifyToken(result.get())) {
authorized = true;
stage.setScene(sceneMain);
}
else
wrongTokenAlert();
}
} catch (IOException e1) {
userNotFoundAlert();
usernameTextField.setText("");
companyTextField.setText("");
}
}});
Node[] items = new Node[6];
items[0] = loginTitle;
items[1] = usernameLabel;
items[2] = usernameTextField;
items[3] = companyLabel;
items[4] = companyTextField;
items[5] = loginButton;
items[6] = registerLink;
gridLogin = buildForm(gridLogin, items);
sceneLogin = new Scene(gridLogin, 300, 200);
return sceneLogin;
}
private Scene buildMainScreen() {
gridMain = new GridPane();
final Label authorizedLabel = new Label("Authorized!");
Button logoutButton = new Button("Logout");
logoutButton.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent e) {
authorized = false;
stage.setScene(sceneLogin);
}});
gridMain.add(authorizedLabel, 0, 0);
gridMain.add(logoutButton, 0, 1);
sceneMain = new Scene(gridMain, 800, 600);
return sceneMain;
}
private Scene buildRegisterScreen() {
gridRegister = new GridPane();
gridRegister.setAlignment(Pos.CENTER);
gridRegister.setVgap(10);
gridRegister.setHgap(10);
sceneRegister = new Scene(gridRegister, 300, 200);
Label userName = new Label("Username:");
final TextField userTextField = new TextField();
Label company = new Label("Company:");
final TextField companyTextField = new TextField();
Label phoneNumber = new Label("Phone nr.:");
final TextField phoneNumberTextField = new TextField();
Button registerButton = new Button("Register");
Hyperlink returnLabel = new Hyperlink();
returnLabel.setText("Go back");
returnLabel.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent e) {
stage.setScene(sceneLogin);
}
});
registerButton.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent event) {
/**
* register response
* 1 - user already exists
* 2 - incorrect username
* 3 - incorrect phonenumber
* 4 - unknown error
* 0 - success
*/
int registerResponse;
UserRegistration userReg = new UserRegistration(userTextField.getText(), companyTextField.getText(), phoneNumberTextField.getText());
try {
registerResponse = userReg.Register();
} catch (IOException e) {
registerResponse = 4;
e.printStackTrace();
}
if (registerResponse == 0) {
userRegisteredConfirmation();
stage.setScene(sceneLogin);
} else {
userRegistrationErrorAlert(registerResponse);
}
}
});
gridRegister.add(userName, 0, 1);
gridRegister.add(userTextField, 1, 1);
gridRegister.add(company, 0, 2);
gridRegister.add(companyTextField, 1, 2);
gridRegister.add(phoneNumber, 0, 3);
gridRegister.add(phoneNumberTextField, 1, 3);
gridRegister.add(registerButton, 1, 4);
gridRegister.add(returnLabel, 0, 4);
return sceneRegister;
}
/**
* Builds a form with items received (items should be sorted)
* @param grid
* @param items
* @return
*/
private GridPane buildForm(GridPane grid, Node[] items) {
int row = 0;
for (int i = 0; i < items.length; i++) {
grid.add(items[i], i, row);
if (i % 2 == 0)
row++;
}
return grid;
}
// ALERTS
/**
* Alert is shown when service returns no user
* @return
*/
private Alert userNotFoundAlert() {
Alert alert = new Alert(Alert.AlertType.ERROR);
alert.setTitle("FENRIR security");
alert.setHeaderText("Error");
alert.setContentText("User not recognized");
alert.showAndWait();
return alert;
}
/**
* Alert is shown when user should enter token
* @return
*/
private TextInputDialog promptTokenAlert() {
TextInputDialog alert = new TextInputDialog("");
alert.setTitle("FENRIR security");
alert.setHeaderText("Token requested");
result = alert.showAndWait();
return alert;
}
/**
* Alert is shown when entered token is wrong
* @return
*/
private Alert wrongTokenAlert() {
Alert alert = new Alert(Alert.AlertType.ERROR);
alert.setTitle("FENRIR security");
alert.setHeaderText("Token incorrect");
alert.showAndWait();
return alert;
}
/**
* Confirmation is shown when registration is completed
* @return
*/
private Alert userRegisteredConfirmation() {
Alert alert = new Alert(Alert.AlertType.INFORMATION);
alert.setTitle("FENRIR security");
alert.setHeaderText("Success");
alert.setContentText("Registration completed");
alert.showAndWait();
return alert;
}
/**
* Alert is shown when an error occurs during registration
* @param errorCode
* @return
*/
private Alert userRegistrationErrorAlert(int errorCode) {
Alert alert = new Alert(Alert.AlertType.ERROR);
alert.setTitle("FENRIR security");
alert.setHeaderText("Error");
String errorMessage;
switch (errorCode) {
case 1: errorMessage = "User already exists.";
break;
case 2: errorMessage = "Incorrect username. Username should be at least 2 characters.";
break;
case 3: errorMessage = "Incorrect phone number. Should be 8 characters and only numbers.";
break;
default: errorMessage = "Unknown error. Contact administrator.";
}
alert.setContentText(errorMessage);
alert.showAndWait();
return alert;
}
}
堆栈跟踪
Exception in Application start method
Exception in thread "main" java.lang.NoSuchMethodException: com.fenrir.desktop.DesktopApplication.main([Ljava.lang.String;)
at java.lang.Class.getMethod(Class.java:1786)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:125)
Process finished with exit code 1
这将解决您的问题，安装 e(fx)clipse 这个插件用于 eclise 但我不知道用于 intellij，或者为您的应用程序添加 facet 作为 javafx 应用程序，如果您添加 facet 则不需要 main 方法，或者使用像这样
public class DesktopApplication extends Application {
@Override
public void start(Stage primaryStage) {
BuildGraphicalUserInterface ui = new BuildGraphicalUserInterface();
ui.initStage(primaryStage);
}
public static void main(String[] args) {
launch(args);
}
}