如何制作自定义Java / JavaFX控制台？

有必要制作自定义控制台。 我有以下代码：

public class Console extends OutputStream{ private Console(ResourceBundle resourceBundle) throws IOException { FXMLLoader loader = new FXMLLoader(this.getClass().getResource("Console.fxml"), resourceBundle); controller = loader.getController(); Scene scene = new Scene((Parent) loader.load()); stage = new Stage(); stage.setScene(scene); show(); } @Override public void write(int b) throws IOException { controller.append(b); } public static Console getInstance(ResourceBundle resourceBundle) { if (console == null) { try { console = new Console(resourceBundle); } catch (IOException e) { e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates. } } return console; } public void show() { stage.show(); } private static Console console = null; private ConsoleController controller; private Stage stage; } 

控制器文件：

 public class ConsoleController implements Initializable { @Override public void initialize(URL url, ResourceBundle resourceBundle) { } @FXML public void append(int i) { textArea.appendText(String.valueOf((char) i)); } @FXML private TextArea textArea; } 

所有这些都是从’start（）’调用的：

  @Override public void start(Stage primaryStage) throws IOException { ... System.setErr(new PrintStream(Console.getInstance(rb))); } 

在exception期间， Console.fxml的textArea中不会打印任何内容，但会引发以下exception：

线程“JavaFX Application Thread”中的exceptionexception：从线程“JavaFX Application Thread”中的UncaughtExceptionHandler抛出java.lang.NullPointerException

我究竟做错了什么？

—— 编辑 ——–

在了解了必须使用多个线程后，我有以下代码：

 public class Console{ private Console(ResourceBundle resourceBundle) throws IOException { FXMLLoader loader = new FXMLLoader(this.getClass().getResource("Console.fxml"), resourceBundle); Parent root = (Parent) loader.load(); controller = loader.getController(); Scene scene = new Scene(root); stage = new Stage(); stage.setScene(scene); show(); if (errorOutputThread != null) { errorOutputThread.interrupt(); try { errorOutputThread.join(); } catch (InterruptedException e) { e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates. } errorOutputThread = null; } if (outOutputThread != null) { outOutputThread.interrupt(); try { outOutputThread.join(); } catch (InterruptedException e) { e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates. } outOutputThread = null; } System.err.flush(); System.out.flush(); outPipedInputStream = new PipedInputStream(); outPipedOutputStream = new PipedOutputStream(outPipedInputStream); System.setOut(new PrintStream(outPipedOutputStream)); errorPipedInputStream = new PipedInputStream(); errorPipedOutputStream = new PipedOutputStream(errorPipedInputStream); System.setErr(new PrintStream(errorPipedOutputStream)); outOutputThread = new Thread(new ConsoleStream(outPipedInputStream, "OUT")); outOutputThread.setDaemon(true); outOutputThread.start(); errorOutputThread = new Thread(new ConsoleStream(errorPipedInputStream, "ERROR")); errorOutputThread.setDaemon(true); errorOutputThread.start(); controller.appendText("Start Console"); } public static Console getInstance(ResourceBundle resourceBundle) { if (console == null) { try { console = new Console(resourceBundle); } catch (IOException e) { e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates. } } return console; } public void show() { stage.show(); } private class ConsoleStream implements Runnable { private ConsoleStream(InputStream in, String type) { inputStream = in; this.type = type; } public void run() { try { InputStreamReader is = new InputStreamReader(inputStream); BufferedReader br = new BufferedReader(is); String read = null; read = br.readLine(); while(read != null) { controller.appendText(read + "\n"); read = br.readLine(); } } catch (IOException e) { e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates. } controller.appendText("Thread" + type + "started"); } private final InputStream inputStream; private String type; } private static Console console = null; private ConsoleController controller; private Stage stage; private PrintStream printStream; private PipedOutputStream customPipedOutputStream; private PipedOutputStream errorPipedOutputStream; private PipedOutputStream outPipedOutputStream; private PipedInputStream customPipedInputStream; private PipedInputStream errorPipedInputStream; private PipedInputStream outPipedInputStream; private Thread customOutputThread; private Thread outOutputThread; private Thread errorOutputThread; } 

但结果只有：“启动控制台”，没有controller.appendText("Thread" + type + "started"); 所以似乎这个线程没有启动。 但为什么？

Answer 1

我认为你必须先加载表单才能获得控制器实例

 FXMLLoader loader = new FXMLLoader(this.getClass().getResource("Console.fxml"),resourceBundle); Parent p = (Parent) loader.load() controller = loader.getController(); Scene scene = new Scene(p);