Swing 应用程序中的 javax.swing.Timer 与 java.util.Timer

Question

is this better to use javax.swing.Timer inside of a swing application instead of using java.util.Timer ?

for example:

Timer timer = new Timer(1000, e -> label.setText(new Date().toString()));
    timer.setCoalesce(true);
    timer.setRepeats(true);
    timer.setInitialDelay(0);
    timer.start();

or

new java.util.Timer().scheduleAtFixedRate(new TimerTask() {
        @Override
        public void run() {
            label.setText(new Date().toString());
        }
    }, 0, 1000);

is there any difference between this two?

Answer 1

The difference:

A java.util.Timer starts its own Thread to run the task on.

A javax.swing.Timer schedules tasks for execution on the EDT .

Now. Swing is single threaded .

You must access and mutate Swing components from the EDT only.

Therefore, to make changes to the GUI every X seconds, use the Swing timer. To do background business logic use the other timer. Or better a ScheduledExecutorService .

Bear one very important thing in mind; if you spend time on the EDT it cannot spend time updating the GUI.

Answer 2

The main difference is that the javax.swing.Timer runs its code on the EDT while the java.util.timer runs on a separate thread. Because of this swing timers are best used if you are manipulating the GUI in any way. Although if you prefer to use a different type of timer then you can still invoke your code on the EDT.

new java.util.Timer().scheduleAtFixedRate(new TimerTask() {
    @Override
    public void run() {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
            label.setText(new Date().toString());
        }
    });
}, 0, 1000);