Java Web implements an example of adding a timed task

This article illustrates how Java Web implements the addition of timed tasks. To share for your reference, the details are as follows:

Timing task time control class

/**
 *  Timed task time control 
 *
 * @author liming
 *
 */
public class TimerManager {
  //  The time interval 
  private static final long PERIOD_DAY = 24 * 60 * 60 * 1000;
  public TimerManager() {
    Calendar calendar = Calendar.getInstance();
    /***  Custom daily 00:00 Execution method  ***/
    calendar.set(Calendar.HOUR_OF_DAY, 0);
    calendar.set(Calendar.MINUTE, 0);
    calendar.set(Calendar.SECOND, 0);
    Date date = calendar.getTime(); // The time it takes to perform a scheduled task 
    //  When starting the server 1 A timed task executes immediately when the time it is executing is less than the current time. 
    //  Therefore, in order to prevent the repeated execution of the task caused by the server restart, the time of executing the timed task needs to be changed to 2 Days. 
    if (date.before(new Date())) {
      date = this.addDay(date, 1);
    }
    Timer timer = new Timer();
    DailyDataTimerTask task = new DailyDataTimerTask();
    //  Task execution interval. 
    timer.schedule(task, date, PERIOD_DAY);
  }
  //  Add or subtract days 
  public Date addDay(Date date, int num) {
    Calendar startDT = Calendar.getInstance();
    startDT.setTime(date);
    startDT.add(Calendar.DAY_OF_MONTH, num);
    return startDT.getTime();
  }
}

Timing task operation principal class

/**
 *  Timing task operation body 
 *
 * @author liming
 *
 */
public class DailyDataTimerTask extends TimerTask {
  private static Logger log = Logger.getLogger(DailyDataTimerTask.class);
  @Override
  public void run() {
    try {
      // Write what you want to execute here 
      System.out.println("come in DailyDataTimerTask");
    } catch (Exception e) {
      log.info("------------- An exception has occurred for parsing information --------------");
    }
  }
}

Timing task listener

/**
 *  Timing task listener 
 *
 * @author liming
 *
 */
public class DailyDataTaskListener implements ServletContextListener {
  public void contextInitialized(ServletContextEvent event) {
    new TimerManager();
  }
  public void contextDestroyed(ServletContextEvent event) {
  }
}

web.xml adds listeners

<!-- Load the daily data update timing task file -->
<listener>
    <listener-class>
      com.honsto.web.job.DailyDataTaskListener
    </listener-class>
</listener>

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