cron schedule freeze | 易学教程

问题

I'm using Cron to schedule an the upload of a file to the server in specific time given by the adminstrator. i created an interface on java, where the user can choose the time of execution of the upload program, and submit the chosen values, once submitted the following method is executed:

public class Reminder {

String minute;
//static int i=0;
String heur;
String substr=",";
String patterns;
List<String> list = null;
List<String> lines = new ArrayList<>();


Timer timer;
 FTPUploadFileDemo up=new FTPUploadFileDemo();

  public void start() throws IOException {
      /************ Get the chosen values from the administrator saved in a CSV file *********************************************************/
      BufferedReader reader;
        try {
            reader = new BufferedReader(new FileReader("C:/Users/BACKENDPC1/Desktop/timer.csv"));


    String line = null;
    while ((line = reader.readLine()) != null) {
        lines.add(line);


    }} catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();}
/**********************create cron patterns *********************************************/

        patterns="";
        for(int i=0; i<lines.size();i++) {
            heur=lines.get(i).substring(0, lines.get(i).indexOf(substr));
            minute=lines.get(i).substring(lines.get(i).indexOf(substr) + substr.length());
            System.out.println("Time selected is: "+heur+","+minute);
            patterns=patterns+minute+" "+heur+" * * *|";

        }
        System.out.println(patterns);


        // Creates the scheduler.
        Scheduler scheduler = new Scheduler();
    // Schedules the task, once every minute.
        scheduler.schedule(patterns,new RemindTask());
        scheduler.start();
        try {
            Thread.sleep(1L * 60L * 1000L);
        } catch (InterruptedException e) {
            System.out.println(e);
        }
        // Stops the scheduler.
        scheduler.stop();

    }

   class RemindTask extends TimerTask  {

      public void run() {



          up.Uplaod();



      }
    }

}

the scheduling works and it runs but, every time the user interface i created freeze, i don't get any error and the program keeps running but the i can't use the interface anymore. can any one help me please.

回答1:

public void start() throws IOException {
..............
    try {
        Thread.sleep(1L * 60L * 1000L);
    } catch (InterruptedException e) {
        System.out.println(e);
    }
...............
}

Why you pause main thread for 60 secounds? Scheduler run his own tasks in separate thread, so you shouldn't interrupt execution of main thread.

ALSO, try to put breakpoints and debug your program step by step and localize problem

And don't write math operations like this: