Java Swing.Timer获得实时毫秒

Question

I'm having a problem in my program. I want to get a real time millisecond that equal to 1000 in 1 seconds. Here's my code:

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.Timer;

class lsen implements ActionListener{
    int ms = 0;
    int s = 0;
    int m = 0;

    public void actionPerformed(ActionEvent e){
        this.ms++;

        if(this.ms == 500){
            this.s++;
            this.ms = 0;
        }
        if(this.s == 60){
            this.m++;
            this.s = 0;
        }
    }

    public int getMS(){
        return this.ms;
    }
    public int getSS(){
        return this.s;
    }
    public int getMM(){
        return this.m;
    }
}

public class stopwatch_main{
    public static void main(String[] args) {
        lsen l = new lsen();
        Timer t = new Timer(0,l);
        t. start();
        while(true){
            System.out.println(l.getMM()+":"+l.getSS()+":"+l.getMS());
        }
    }
}

Is there any other way in getting the millisecond rather than declaring a integer and incrementing it?

Answer 1

1. You will want to get rid of that while (true) and instead use the Swing Timer in its place since that is what the Timer is for -- to repeatedly make calls in a Swing GUI without having to resort to a thread-breaking while (true) construct.
2. You will want to give your Timer a reasonable delay time. 0? Common sense tells you not to use this. 12, 15 -- better.
3. For a Swing Timer to work, you need to have an active Swing event thread, and this can be obtained by showing a Swing GUI, any GUI such as a JOptionPane.

   ---

For example:

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.Timer;

class Lsen implements ActionListener {
   public static final int MSECS_PER_SEC = 1000;
   public static final int SECS_PER_MIN = 60;
   public static final int MIN_PER_HR = 60;
   private static final String TIME_FORMAT = "%02d:%02d:%02d:%03d";

   private long startTime;
   private JTextField timeField;

   public Lsen(JTextField timeField) {
      this.timeField = timeField;
   }

   public void actionPerformed(ActionEvent e) {
      if (startTime == 0L) {
         startTime = System.currentTimeMillis();
      } else {
         long currentTime = System.currentTimeMillis();
         int diffTime = (int) (currentTime - startTime);

         int mSecs = diffTime % MSECS_PER_SEC;
         diffTime /= MSECS_PER_SEC;

         int sec = diffTime % SECS_PER_MIN;
         diffTime /= SECS_PER_MIN;

         int min = diffTime % MIN_PER_HR;
         diffTime /= MIN_PER_HR;

         int hours = diffTime;

         String time = String.format(TIME_FORMAT, hours, min, sec, mSecs);
         // System.out.println("Time: " + time);
         timeField.setText(time);
      }
   }
}

public class StopWatchMain {
   private static final int TIMER_DELAY = 15;

   public static void main(String[] args) {
      final JTextField timeField = new JTextField(10);
      timeField.setEditable(false);
      timeField.setFocusable(false);
      JPanel panel = new JPanel();
      panel.add(new JLabel("Elapsed Time:"));
      panel.add(timeField);

      Lsen l = new Lsen(timeField);
      Timer t = new Timer(TIMER_DELAY, l);
      t.start();
      JOptionPane.showMessageDialog(null, panel);
      t.stop();
   }
}

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Edit
You ask about the meaning of the long data type. Please have a look here: Primitive Data Types . You'll see that long means long integer, and so you can think of it as being similar to int but able to tolerate much larger positive and negative values without overflowing.