如何使联网的JavaFX应用程序正常退出？

Question

I am making a simple networked Tic-Tac-Toe game using JavaFX. To initialize the server-client connection, I have two classes: serverSelectHandler and clientSelectHandler. To establish a connection, the server class creates a ServerSocket, creates a normal Socket, and then creates a Thread that handles data transmission. The client class is the same, except that it does not have a ServerSocket.

When a Thread is created, it associates itself with the RemoteInputHandler class. This class overrides the run() method in Runnable. Here's a block of code that it adds:

String input = netComm.reader.readLine();
while (input != null)
{
    // Make a separate copy of the input string 
    String inputCopy = input;
    // Post a work order to process the command on the GUI thread
    Platform.runLater( () -> {handleRemote(inputCopy);});
    // Get the next remote input
    input = netComm.reader.readLine();
}

As you can see, this method uses a lambda expression to queue up work orders. I have a feeling that this may be what is causing my problem.

The problem is that Platform.exit() does not fully terminate instances of this application. It causes the window to close, but the process stays running in the background. If I omit setting up a thread in ClientSelectHandler, this problem does not happen. However, this causes the client to ignore commands sent by the server.

http://jabahan.com/javafx-application-not-properly-closed-even-if-the-platform-exit-is-used/

The page linked above discusses a very similar problem. This is why I think my problem may have something to do with extra threads that are not being closed. I can provide more code and/or explanation if necessary. Thanks for reading this.

Answer 1

If you just want the application to exit immediately, you can call System.exit(). However, if you want to be a little cleaner you'll have to override your Application.stop() method to close all your background threads before exiting. You might want to look at the Worker and Task classes to handle background threads.

http://docs.oracle.com/javafx/2/threads/jfxpub-threads.htm