import java.io.*;
import java.text.*;
import java.util.*;
import javax.swing.JOptionPane;
public class ReminderService {
   Timer timer = new Timer();
   class Item extends TimerTask {
      String message;
      Item(String m) {
         message = m;
      }
      public void run() {
         message(message);
      }
   }
   public static void main(String[] argv) throws IOException {
      new ReminderService().load();
   }
   protected void load() throws IOException {
      SimpleDateFormat formatter =new SimpleDateFormat ("yyyy MM dd hh mm");
      SimpleDateFormat formatter = new SimpleDateFormat ("yyyy MM dd hh mm");
      //设置提醒时间和提醒内容
      String aLine="2021 05 01 21 14 时间提醒成功";
      ParsePosition pp = new ParsePosition(0);
      Date date = formatter.parse(aLine, pp);
      if (date == null) {
          message("Invalid date in " + aLine);
      }
      String mesg = aLine.substring(pp.getIndex());
      timer.schedule(new Item(mesg), date);
   }
   void message(String message) {
      System.out.println("\007" + message);
      JOptionPane.showMessageDialog(null,message,"Timer Alert",           
         JOptionPane.INFORMATION_MESSAGE);   
   }
}