暂停并恢复ExecutorService或关闭并重新启动Java Executor服务

我正在一个javaFX项目上工作，在该项目中，用户只需浏览几个文件，创建一个文件队列，单击“开始上传”，然后在指定路径上上传这些文件的开始。现在，当用户单击“暂停”按钮时，必须暂停上载过程，而在单击“恢复”时，必须从暂停点重新开始该过程。因此，到目前为止，我已经通过Executors.newSingleThreadExecutor（）创建了一个对象（文件）队列。并提交了任务。在我看来，taks类被称为Item。现在，当用户单击暂停按钮时，我调用executorService的shutdownnow（）方法。当用户单击简历时，我将创建一个Executorservice的全新实例。但是，当我通过executor.execute方法提交作业时，它将跳过当前任务并继续执行下一个任务，依此类推。因此，我需要从最后执行的任务开始。

public class UploadManagerController implements Initializable {

private static boolean checkRunning = true;

private static String currentClient;
private static int currentView = 0;
private static int checkLastSelectedQueue = 0;
private static Timeline fiveSecondsWonder;
private List<File> uploadDir;
private static long currentSelectedRow = -1;
private static ThreadFactory threadFactory;
private static ExecutorService executor;
private static Thread t;
private static LinkedHashMap<String, ObservableList> clientUploadInfo;
private static HashMap<String, Long> clientUploadInfoCount;
private static HashMap<String, String> clientUploadInfoTotalSize;
private static HashMap<String, Double> clientUploadInfoTotalSizeLong;


  public static class Item extends Task<Void> {

    public SimpleStringProperty fileName = new SimpleStringProperty();
    public SimpleStringProperty fileSize = new SimpleStringProperty();
    public SimpleStringProperty ETA = new SimpleStringProperty();
    public SimpleStringProperty speed = new SimpleStringProperty();
    public SimpleStringProperty status = new SimpleStringProperty();
    public SimpleDoubleProperty progress = new SimpleDoubleProperty();
    public SimpleObjectProperty clientName = new SimpleObjectProperty();
    public SimpleStringProperty path = new SimpleStringProperty();
    public SimpleLongProperty id = new SimpleLongProperty();
    public File file;
    public long time = 0;

    // Getter and setter of above variables

    @Override
    protected Void call() throws Exception {
        File filee = this.getFile();
        FileInputStream is = new FileInputStream(filee); 
        String mRecordingFile = "UserSpecifiedPath\\" + this.getFileName();

        File fl = new File(mRecordingFile);
        if (fl.exists() && (this.getStatus().equals("error") != true || this.getStatus().equalsIgnoreCase("stopped") != true)) {
            fl.renameTo(new File("UserSpecifiedPath\\" + Util.getTime() + "_" + fl.getName()));

        }

        boolean checkDelete = false;
        for (String key : clientUploadInfo.keySet()) {
            if (clientUploadInfo.get(key).contains(this)) {
                checkDelete = true;
                break;
            }
        }
        if ( checkDelete) {
            java.nio.channels.FileChannel fc = is.getChannel();
            long totalSize = filee.length();
            long total = totalSize / 10000;
            java.nio.ByteBuffer bb = java.nio.ByteBuffer.allocate(10000);

            byte[] bytes;

            while (fc.read(bb) > 0) {

                bb.flip();
                bytes = bb.array();
                File f = new File(mRecordingFile);
                try (FileOutputStream fOut = new FileOutputStream(mRecordingFile, true)) {
                    fOut.write(bytes);
                }
                      bb.clear();
            }
        }


        return null;
    }
}

 @Override
public void initialize(URL url, ResourceBundle rb) {
    clientUploadInfo = new LinkedHashMap<>();
          threadFactory = new ThreadFactory() {
        @Override
        public Thread newThread(Runnable r) {

            t = new Thread(r);
            try {
                t.join();
            } catch (InterruptedException ex) {
                System.out.println("inte");
            }
            t.setDaemon(true);
            return t;
        }
    };
    executor = Executors.newSingleThreadExecutor(threadFactory);
}

  @FXML
private void startupload(ActionEvent event) {
    ObservableList<Item> temp = FXCollections.observableArrayList();
    temp.addAll(clientUploadInfo.get(currentClient));
    currentView = 1;
    checkRunning = true;
    if (executor.isShutdown()) {
        executor = null;
        t=null;
        threadFactory = null;
        threadFactory = new ThreadFactory() {

            @Override
            public Thread newThread(Runnable r) {
                 t = new Thread(r);
                try {
                    t.join();
                } catch (InterruptedException ex) {
                    Logger.getLogger(UploadManagerController.class.getName()).log(Level.SEVERE, null, ex);
                }

                t.setDaemon(true);
                return t;
            }
        };
        executor = Executors.newSingleThreadExecutor(threadFactory);


         for (Item itm : temp) {
            if (itm.getStatus().equalsIgnoreCase("In Active") || itm.getStatus().equalsIgnoreCase("queued") || itm.getStatus().equalsIgnoreCase("error") || itm.getStatus().equalsIgnoreCase("stopped")) {

                executor.submit(itm);
            }
        }

    } else {
        for (Item itm : temp) {
            if (itm.getStatus().equalsIgnoreCase("In Active") || itm.getStatus().equalsIgnoreCase("queued") || itm.getStatus().equalsIgnoreCase("error") || itm.getStatus().equalsIgnoreCase("stopped")) {

                executor.execute(itm);
            }
        }
    }
}

@FXML
private void stopUpload(ActionEvent event) {
    checkRunning = false;
    executor.shutdownNow();

}
}

抱歉，我的英语很抱歉，但是让我尝试解释一下，在上面的代码中，它们是STARTUPLOAD和STOPUPLOAD这两种方法，单击javafx按钮时会调用这两种方法，因此，当我第一次单击startupload按钮时，它将开始在clientUploadInfo.get（KEY）hasMap，我单击添加文件按钮时会保持它，我没有提到使代码更短的代码，Item类包含所有详细信息。在单击“停止上载”按钮时，调用stopUpload方法，在再次单击“开始上载”按钮时，调用startUpload方法，但要恢复上载过程，在我的情况下，请记住它会继续上载，但从下一项开始，它将保留当前项就像单击“停止”按钮时一样 任何帮助，将不胜感激 。提前致谢。