Timer Timer __java-concurrency

1. Overview

Perform specific tasks on a regular basis. 2. Classes and Methods 2.1Timer

Java.util.Timer

A timer corresponds to a thread. A timer can schedule multiple tasks. If a task has an exception, the timer thread may not work properly, and other tasks are implicated. It is generally used to schedule lightweight tasks.

Java.util.timer#schedule (java.util.TimerTask task, java.util.Date when)

Perform a task at a specific time.

Java.util.timer#scheduleatfixedrate (timertask task, Date when, long period)

A task is executed every period, starting at a specific time.

2.2 TimerTask

Java.util.TimerTask

Abstract class, which implements the Runnable interface.

Java.util.timertask#cancel ()

Cancels the timed task.

Note: Used TimerTask is like worn socks, no way to be timer dispatch. TimerTask, which have been schedule or cancel, belong to the used TimerTask.
3. Sample Code

Common steps to see below.

1. Create a Class A that inherits from the TimerTask class and rewrite the run () method.

2. Create a Timer object, call the schedule () method, and pass the object of the custom Class A as an argument.

Import Java.util.Timer;

Class Timertasktest extends TimerTask {
	@Override public
	void Run () {
		System.out.println ("3 seconds to say hi");
	}
}

public class Timerdemo {public
	static void Main (string[] args) {
		Timer timer = new timer ();
		void Java.util.Timer.schedule (timertask task, long delay, long period)
		//delay time after period () every Task.run time interval () The function time unit is millisecond
		timer.schedule (New Timertasktest (), 0, 3000)
	;
}
 * * * 3 seconds say hi 
 * 3 seconds once say hi * 
 3 seconds say hi * 
 3 seconds say hi
 *  ...
 */