传递对javafx.application.application的引用

我将尝试演示在java程序和javafx程序之间传递引用的一些不同方法。
我把它贴出来,希望它能帮助将来有类似需求的读者。我也希望它可以鼓励其他答案与其他解决办法。

interface Observe{ void update(int i); }

一个java类,表示一个正在退出的业务应用程序:

public class JavaApp {

    private Observe observer;  private int counter = 0;

    JavaApp(Observe observer){  //not null safe
        this.observer = observer;
    }

    void process() {            
        new Timer().scheduleAtFixedRate(new TimerTask() {
            @Override
            public void run() {
                observer.update(counter >=100 ? 0 : ++counter);
            }
        }, 1000,1000);
    }
}

一个java fx应用程序,应该添加到现有的业务应用程序中,聆听它并充当视图:

public class JavaFxApp extends Application implements Observe{

    private Label label;

    @Override public void start(Stage stage) {
        label = new Label("waiting");
        BorderPane pane = new BorderPane(label);
        Scene scene = new Scene(pane, 100, 100);
        stage.setScene(scene);
        stage.show();
    }

    @Override public void update(int i) {
        Platform.runLater(()-> label.setText(String.valueOf(i)));
    }
}

我们如何共享一个引用,在本例中是对 Observe 实例,在两个应用程序之间?

start() 方法作为应用程序的入口点 (见James D answer
如果您想将现有的java应用程序与javafx绑定并使用javafx,这是简单而直接的 Application

public class JavaFxApp extends Application implements Observe{

    private Label label;

    @Override public void start(Stage stage) {  
        JavaApp main = new JavaApp(this);
        label = new Label("waiting");
        BorderPane pane = new BorderPane(label);
        Scene scene = new Scene(pane, 100, 100);
        stage.setScene(scene);
        stage.show();

        new Thread(()-> { main.process();}).start(); //launch the business process
    }

    @Override   public void update(int i) {
        Platform.runLater(()-> label.setText(String.valueOf(i)));
    }

    public static void main(String[] args) { launch();  }
}

方法2:使用JavaFX9平台启动
这是我找到的最好的解决办法,当你 不能 Application#start
如费比安所示 answer 应用 . 你所要做的就是修改 main java应用程序的名称:

public class JavaApp {

    private Observe observer;  private int counter = 0;

    JavaApp(Observe observer){//not null safe
        this.observer = observer;
    }

    void process() {
        new Timer().scheduleAtFixedRate(new TimerTask() {
            @Override   public void run() {
                observer.update(counter >=100 ? 0 : ++counter);
            }
        }, 1000,1000);
    }

    public static void main(String[] args) {
        JavaFxApp view = new JavaFxApp(); //initialize JavaFx application
        JavaApp main = new JavaApp(view);

        Platform.startup(() -> {//launch JavaFx application 

            Stage stage = new Stage();
            try {
                view.start(stage);
            } catch (Exception ex) {ex.printStackTrace();}
        });

        main.process(); //run business process 
    }
}

例如,在java fx应用程序中引入静态getter:

public class JavaFxApp extends Application {

    private static Label label = new Label("waiting");

    @Override public void start(Stage stage) {  
        BorderPane pane = new BorderPane(label);
        Scene scene = new Scene(pane, 100, 100);
        stage.setScene(scene);
        stage.show();
    }

    static Observe getObserver() {
        return JavaFxApp::update;
    }

    private static void update(int i) {
        Platform.runLater(()-> label.setText(String.valueOf(i)));
    }
}

并在java应用程序中使用它:

public class JavaApp {

    private Observe observer;  private int counter = 0;

    JavaApp(Observe observer){//not null safe
        this.observer = observer;
    }

    void process() {
        new Timer().scheduleAtFixedRate(new TimerTask() {
            @Override
            public void run() {
                observer.update(counter >=100 ? 0 : ++counter);
            }
        }, 1000,1000);
    }

    public static void main(String[] args){
        new Thread(()-> Application.launch(JavaFxApp.class)).start();
        Observe observer = JavaFxApp.getObserver(); //get static observer reference
        JavaApp main = new JavaApp(observer);
        main.process();
    }
}

获取静态引用的更好方法可能是(基于 this 回答):

public class JavaFxApp extends Application implements Observe{

    private static final CountDownLatch latch = new CountDownLatch(1);
    private static Observe observer = null;
    private Label label;

   @Override public void init() {
       observer = this;
       latch.countDown();
    }

    @Override public void start(Stage stage){
        label = new Label("waiting");
        BorderPane pane = new BorderPane(label);
        Scene scene = new Scene(pane, 100, 100);
        stage.setScene(scene);
        stage.show();
    }

    @Override public void update(int i) {
        Platform.runLater(()-> label.setText(String.valueOf(i)));
    }

    static Observe getObserver() {
        try {
            latch.await();
        } catch (InterruptedException e) { e.printStackTrace();  }

        return observer;
    }
}