JavaFX登录界面——IMAU

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.text.Font;
import javafx.geometry.HPos;
import javafx.geometry.Pos;
import javafx.scene.layout.GridPane;
import javafx.geometry.Insets;
import javafx.stage.Stage;
public class HelloApplication extends Application{

    @Override
    public void start(Stage primaryStage){
        GridPane pane=new GridPane();
        pane.setAlignment(Pos.CENTER);
        pane.setPadding(new Insets(11,12,13,14));
        pane.setHgap(5);
        pane.setVgap(5);

        Label label1=new Label("Welcome");
        label1.setFont(Font.font(20));
        pane.add(label1,0,0);
        pane.add(new Label("User Name:"),0,1);
        pane.add(new TextField(),1,1);
        pane.add(new Label("Password:"),0,2);
        final PasswordField pb = new PasswordField();
        pane.add(pb,1,2);
        Button bt=new Button("Sign in");
        pane.add(bt,1,3);
        GridPane.setHalignment(bt,HPos.RIGHT);

        if(pb.getText().equals("123")) {

            bt.setOnAction(new EventHandler() {
                public void handle(ActionEvent e) {
                    Alert alert = new Alert(Alert.AlertType.INFORMATION);
                    alert.setContentText("登录成功");
                    alert.setTitle("登录成功");
                    alert.setHeaderText("");
                    alert.show();
                }
            });
        }
        else {

            bt.setOnAction(new EventHandler() {
                public void handle(ActionEvent e) {
                    Alert alert = new Alert(Alert.AlertType.ERROR);
                    alert.setContentText("登录失败");
                    alert.setTitle("登录失败");
                    alert.setHeaderText("");
                    alert.show();
                }
            });
        }

        Scene scene=new Scene(pane,400,250);
        primaryStage.setTitle("JavaFx Welcome");
        primaryStage.setScene(scene);
        primaryStage.show();
    }
    public static void main(String args){
        Application.launch(args);
    }
}