Question

Hello Guys我有一个问题，如何在Javafx中的后台运行任务

目前的情况是我在javafx中创建了一个复制功能，它工作得非常好，但是如果我们有更多的文件，那么它进入无响应模式直到进程完成，日志也不会打印在我的textarea中，每个文件都被复制到受尊重的文件夹中，但问题是它被挂起，直到过程完成，

另外一个问题如何永远运行这个程序意味着无论何时新文件进入源目录，它都会自动进入目标目录。

这是我的代码

try
        {
            sourceFile = new File(sourcePath).listFiles();
            syslog.appendText("\nTotal Files in the Directory : " + sourceFile.length);
            for(int i = 0; i<sourceFile.length;i++)
            {
                if(sourceFile[i].isFile())
                {
                    String file = sourceFile[i].getName();
                    String extension = Files.getFileExtension(file);
                    if(!new File(destinationPath+"/"+extension.toUpperCase()).exists())
                    {
                        if(new File(destinationPath+"/"+extension.toUpperCase()).mkdir())
                        {
                            syslog.appendText("\nDirectory Created : " + destinationPath+"/"+extension.toUpperCase());
                            try
                            {
                                if(!new File(destinationPath+"/"+extension.toUpperCase()+"/"+file).exists())
                                {
                                    syslog.appendText("\nFile "+file+" is processing to copy to "+destinationPath+"/"+extension.toUpperCase());
                                    copyFile(sourceFile[i],new File(destinationPath+"/"+extension.toUpperCase()+"/"+file));
                                    syslog.appendText("\nFile "+file+" is successfully copied to "+destinationPath+"/"+extension.toUpperCase());
                                    if(sourceFile[i].delete())
                                        syslog.appendText("\nFile "+file+" is successfully deleted from "+sourcePath);
                                    else
                                        syslog.appendText("\nError in deleting File "+file+" from "+sourcePath);
                                }
                            }
                            catch(Exception e)
                            {
                                e.printStackTrace();
                                syslog.appendText("\nSome Error Occurred while copying the File : "+sourceFile[i]);
                            }
                        }
                    }
                    else
                    {
                        try
                        {
                            if(!new File(destinationPath+"/"+extension.toUpperCase()+"/"+file).exists())
                            {
                                syslog.appendText("\nFile "+file+" is processing to copy to "+destinationPath+"/"+extension.toUpperCase());
                                copyFile(sourceFile[i],new File(destinationPath+"/"+extension.toUpperCase()+"/"+file));
                                syslog.appendText("\nFile "+file+" is successfully copied to "+destinationPath+"/"+extension.toUpperCase());
                                if(sourceFile[i].delete())
                                    syslog.appendText("\nFile "+file+" is successfully deleted from "+sourcePath);
                                else
                                    syslog.appendText("\nError in deleting File "+file+" from "+sourcePath);
                            }
                        }
                        catch(Exception e)
                        {
                            e.printStackTrace();
                            syslog.appendText("\nSome Error Occurred while copying the File : "+sourceFile[i]);
                        }
                    }
                }
            }
            syslog.appendText("\nFinished..........");
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }

这是复制功能

    private static void copyFile(File source, File destination)
        throws IOException {
    FileChannel inputChannel = null;
    FileChannel outputChannel = null;
    try {
        inputChannel = new FileInputStream(source).getChannel();
        outputChannel = new FileOutputStream(destination).getChannel();
        outputChannel.transferFrom(inputChannel, 0, inputChannel.size());
    } finally {
        inputChannel.close();
        outputChannel.close();
    }
}

Answer 1

我会使用任务，比如这样：

    public class CopyFileTask<Void> extends Task<Void> {

    @Override
    protected void succeeded() {
        super.succeeded();
        // e.g. show "copy finished" dialog
    }

    @Override
    protected void running() {
        super.running();
        // e.g. change mouse courser
    }

    @Override
    protected void failed() {
        super.failed();
        // do stuff if call threw an excpetion
    }

    @Override
    protected Void call() {
        // do expensive the expensive stuff
        copyStuff(source, destination)
        return null ;
    }
}

便捷方法succeeded，running和failed在JavaFX GUI线程中执行，而call中的内容在另一个线程中执行。要运行任务，我建议将其提交到ExecuterService

 ExecutorService exService = Executors.newSingleThreadExecutor();
 exService.submit(new CopyFileTask());

Answer 2

您需要创建一个Task并将其添加到新线程中。它看起来像这样：

        Task<T> backgroundTask = new Task<T>() {
        @Override
        protected T call() throws Exception {
            return null;
        }

        @Override
        public void run() {
            try {
                    copyFile(source,destination); //or any other operation you want to have in a thread.
                        } catch (IOException e) {
                           e.printStackTrace();
                        }
                }
        }
    };
    Thread backgroundThread = new Thread(backgroundTask);
    backgroundThread.setDaemon(true); //true if you want to have it running excuslivly when having your parent-threat running

您可以使用

调用并运行此线程一次

 backgroundThread.run();

您可以使用

检查线程的状态

 backgroundThread.state();

如果您想查看例如，可能会有帮助如果您的主题仍在进行中。

考虑与javafx线程的冲突。如果要更改javafx-thread访问的对象，则需要执行

 Platform.runLater(new Runnable() {/*your impact on javafx*/});

在javafx

2 个答案: