如何在java中多次调用launch（）

如何在java中多次调用launch（）我被赋予一个exception，如“主错误：java.lang.IllegalStateException：应用程序启动不能多次调用”

我已经在我的Java应用程序中创buildrest清单，当请求来到它调用javafx和完成webview操作之后打开webview使用Platform.exit（）方法closuresjavafx窗口。 当第二个请求来得到这个错误如何reslove这个错误。

JavaFx应用程序代码：

public class AppWebview extends Application { public static Stage stage; @Override public void start(Stage _stage) throws Exception { stage = _stage; StackPane root = new StackPane(); WebView view = new WebView(); WebEngine engine = view.getEngine(); engine.load(PaymentServerRestAPI.BROWSER_URL); root.getChildren().add(view); engine.setJavaScriptEnabled(true); Scene scene = new Scene(root, 800, 600); stage.setScene(scene); engine.setOnResized(new EventHandler<WebEvent<Rectangle2D>>() { public void handle(WebEvent<Rectangle2D> ev) { Rectangle2D r = ev.getData(); stage.setWidth(r.getWidth()); stage.setHeight(r.getHeight()); } }); JSObject window = (JSObject) engine.executeScript("window"); window.setMember("app", new BrowserApp()); stage.show(); } public static void main(String[] args) { launch(args); } 

RestClient方法：调用JavaFX应用程序

 // method 1 to lanch javafx javafx.application.Application.launch(AppWebview.class); // method 2 to lanch javafx String[] arguments = new String[] {"123"}; AppWebview .main(arguments); 

Answer 1

您不能多次调用JavaFX应用程序的launch() ，这是不允许的。

从javadoc：

 It must not be called more than once or an exception will be thrown. 

build议定期展示一个窗口

1. 只需调用一次Application.launch() 。
2. 使用Platform.setImplicitExit(false)保持JavaFX运行时在后台运行，以便JavaFX在隐藏最后一个应用程序窗口时不会自动closures。
3. 下次需要另一个窗口时，在Platform.runLater()包装show()调用窗口，以便在JavaFX应用程序线程上执行调用。

如果您正在混合Swing，则可以使用JFXPanel而不是应用程序 ，但使用模式将与上面所述类似。

Wumpus样品

 import javafx.animation.PauseTransition; import javafx.application.*; import javafx.geometry.Insets; import javafx.scene.Scene; import javafx.scene.control.Label; import javafx.stage.Stage; import javafx.util.Duration; import java.util.*; // hunt the Wumpus.... public class Wumpus extends Application { private static final Insets SAFETY_ZONE = new Insets(10); private Label cowerInFear = new Label(); private Stage mainStage; @Override public void start(final Stage stage) { // wumpus rulez mainStage = stage; mainStage.setAlwaysOnTop(true); // the wumpus doesn't leave when the last stage is hidden. Platform.setImplicitExit(false); // the savage Wumpus will attack // in the background when we least expect // (at regular intervals ;-). Timer timer = new Timer(); timer.schedule(new WumpusAttack(), 0, 5_000); // every time we cower in fear // from the last savage attack // the wumpus will hide two seconds later. cowerInFear.setPadding(SAFETY_ZONE); cowerInFear.textProperty().addListener((observable, oldValue, newValue) -> { PauseTransition pause = new PauseTransition( Duration.seconds(2) ); pause.setOnFinished(event -> stage.hide()); pause.play(); }); // when we just can't take it anymore, // a simple click will quiet the Wumpus, // but you have to be quick... cowerInFear.setOnMouseClicked(event -> { timer.cancel(); Platform.exit(); }); stage.setScene(new Scene(cowerInFear)); } // it's so scary... public class WumpusAttack extends TimerTask { private String[] attacks = { "hugs you", "reads you a bedtime story", "sings you a lullaby", "puts you to sleep" }; // the restaurant at the end of the universe. private Random random = new Random(42); @Override public void run() { // use runlater when we mess with the scene graph, // so we don't cross the streams, as that would be bad. Platform.runLater(() -> { cowerInFear.setText("The Wumpus " + nextAttack() + "!"); mainStage.sizeToScene(); mainStage.show(); }); } private String nextAttack() { return attacks[random.nextInt(attacks.length)]; } } public static void main(String[] args) { launch(args); } } 

Answer 2

试试这个，我试过了，发现成功了

 @Override public void start() { super.start(); try { // Because we need to init the JavaFX toolkit - which usually Application.launch does // I'm not sure if this way of launching has any effect on anything new JFXPanel(); Platform.runLater(new Runnable() { @Override public void run() { // Your class that extends Application new ArtisanArmourerInterface().start(new Stage()); } }); } catch (Exception e) { e.printStackTrace(); } }