btOK.setOnAction(

    new EventHandler<ActionEvent> {

        public void handle

            (ActionEvent e) {

            System.out.println

            (e.getSource());

        }

}

); // Something missing here

import javafx.application.Application;

import javafx.stage.*;

import javafx.scene.*;

import javafx.scene.control.Button;

import javafx.scene.layout.VBox;

import javafx.geometry.*;

import javafx.scene.layout.*;

import javafx.scene.image.*;

import java.util.*;

public class getcards extends Application {

@Override

public void start(Stage primaryStage){

    VBox pane=new VBox(5);

    pane.setPadding(new Insets(5,5,5,5));

    Cardspane cards=new Cardspane();

    pane.getChildren().add(cards);

    Button btRefresh = new Button("Refresh");

    pane.getChildren().add(btRefresh);

    pane.setAlignment(Pos.CENTER);

    VBox.setMargin(btRefresh, new Insets(5,5,5,5));

    btRefresh.setOnAction(e->{cards.refresh();});

    Scene scene=new Scene(pane,400,400);

    primaryStage.setTitle("etcards");

    primaryStage.setScene(scene);

    primaryStage.show();

    }

    public class Cardspane extends HBox{

        private Integer[] cardsNum ={1,2,3,4,5,6,7,8,9

               ,10,11,12,13,14,15,16,17,18,19,120,21,22

               ,23,24,25,26,27,28,29,30,31,32,33,34,35,

               36,37,38,39,40,41,42,43,44,45,46,47,48,49,50

               ,51,52,53,54

        };

        private ArrayList<Integer>list =new ArrayList<>(Arrays.asList(cardsNum));

        private ImageView p1;

        private ImageView p2;

        private ImageView p3;

        private ImageView p4;

        public void CardsPane()

        {

            setSpacing(5);

            Collections.shuffle(list);

            p1=new ImageView("实验五/card/"+Integer.valueOf(list.get(0))+".png");

            p2=new ImageView("实验五/card/"+Integer.valueOf(list.get(1))+".png");

            p3=new ImageView("实验五/card/"+Integer.valueOf(list.get(2))+".png");

            p4=new ImageView("实验五/card/"+Integer.valueOf(list.get(3))+".png");

            super.getChildren().addAll(p1,p2,p3,p4);

        }

　　public void refresh(){

　　　　Collections.shuffle(list);

　　　　super.getChildren().removeAll(p1,p2,p3,p4);

　　　　p1=new ImageView("实验五/card/"+Integer.valueOf(list.get(0))+".png");

　　　　p2=new ImageView("实验五/card/"+Integer.valueOf(list.get(1))+".png");

　　　　p3=new ImageView("实验五/card/"+Integer.valueOf(list.get(2))+".png");

　　　　p4=new ImageView("实验五/card/"+Integer.valueOf(list.get(3))+".png");

　　　　super.getChildren().addAll(p1,p2,p3,p4);

}

    }   

　　public static void main(String[] args) {

    　　launch(args);

　　}
}

package javaseniorprograme;

import javafx.application.Application;

import javafx.event.ActionEvent;

import javafx.scene.Scene;

import javafx.scene.control.Button;

import javafx.scene.layout.BorderPane;

import javafx.scene.paint.Color;

import javafx.scene.shape.Rectangle;

import javafx.stage.Stage;

/**

 * 15.2 (旋转一个四边形）

 * @author ASUS

 */

public class Exercise15_02 extends Application{

    private double angle = 0;

    @Override

    public void start(Stage primaryStage){

        BorderPane root = new BorderPane();

        BorderPane bottom = new BorderPane();

        // 创建一个按钮

        Button btOK = new Button("Rotate");

        // 创建一个矩形

        Rectangle rec = new Rectangle(150, 80);

        // 设置矩形轮廓颜色

        rec.setStroke(Color.BLACK);

        // 设置矩形填充色

        rec.setFill(Color.WHITE);

        // 按钮事件处理

        btOK.setOnAction((ActionEvent e) -> {

            angle += 15;

            rec.setRotate(angle);

            System.out.println(e.getSource());

        });

        // 控件布局

        root.setCenter(rec);

        bottom.setCenter(btOK);

        root.setBottom(bottom);

        // 场景

        Scene scene = new Scene(root, 320, 200);

        primaryStage.setTitle("Exercise15_02");

        primaryStage.setScene(scene);

        primaryStage.show();

    }

    // 主方法

    public static void main(String[] args){

        launch(args);

    }

}