Java Timer Implementation Summary

Preface: There are 3 main implementations of Java timers: JDK components, Spring Task,quartz framework.

1. JDK Components
(1) java.util. TimerTask

Mytimertask.java:

 Public classMytimertaskextendsTimerTask {@Override Public voidrun () {System.out.println ("Mytimertask, now:" +NewSimpleDateFormat ("Yyyy-mm-dd HH:mm:ss"). Format (NewDate ())); } Public Static voidMain (string[] args) {Timer timer=NewTimer (); Timer.schedule (NewMytimertask (), 1000, 1000); //Timer.cancel ();//Stop Scheduler 　　 }}

(2) Java.util.concurrent. Scheduledthreadpoolexecutor (Recommended for use after jdk5.0+)

Myscheduledtask.java:

Public  classimplements  Runnable {  publicvoid  run () { System.out.println (new SimpleDateFormat ("Yyyy-mm-dd HH:mm:ss"). Format (new   　　Date ())); }}

Myscheduledexecutor.java:

 Public classMyscheduledexecutor { Public Static voidMain (string[] args) {Scheduledthreadpoolexecutor executor=NewScheduledthreadpoolexecutor (10); Scheduledfuture Future= Executor.schedulewithfixeddelay (NewMyscheduledtask (), 1000, 1000, Timeunit.milliseconds); //Future.cancel (true);//Stop Timer task, timer cannot stop timer task, can only close scheduler//Executor.shutdown ();//Shutdown Scheduler 　　 }}

Comparison: Java.util.concurrent.ScheduledThreadPoolExecutor is more flexible and efficient than java.util.TimerTask.

2. Spring Task
(1) Configuration method implementation
Taskjob.java:

@Service  Public class taskjob {  publicvoid  job1 () {System.out.println(new SimpleDateFormat ("　　Yyy-mm-dd HH:mm:ss "). Format (new  Date ())); }}

Spring.xml:

<Beansxmlns= "Http://www.springframework.org/schema/beans"Xmlns:task= "Http://www.springframework.org/schema/task". .. xsi:schemalocation= "... http://www.springframework.org/schema/taskhttp://www.springframework.org/schema/task/spring-task-3.0.xsd"> 　　 <!--Automatic injection of timed task components - 　　 <Context:component-scanBase-package= "XXX" /> 　　 <!--defining timed task scheduling policies - 　　 <Task:scheduled-tasks> 　　　　 <task:scheduledref= "Taskjob"Method= "Job1"Cron= "0/1 * * * *?" /> 　　 </Task:scheduled-tasks></Beans>

(2) Implementation of the annotation method
Taskjob2.java:

@Component  Public class  /**  * Once every second   / @Scheduled (cron= "0/1 * * * *?") )  publicvoid  job2 () {System.out.println(new SimpleDateFormat (　　"Yyyy-mm-dd HH:mm:ss"). Format (new  Date ())); }}

Spring.xml:

<Beansxmlns= "Http://www.springframework.org/schema/beans"Xmlns:context= "Http://www.springframework.org/schema/context"Xmlns:task= "Http://www.springframework.org/schema/task". .. xsi:schemalocation= "... http://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/ spring-context-3.0.xsdhttp://www.springframework.org/schema/taskhttp://www.springframework.org/schema/task/ Spring-task-3.0.xsd "> 　　 <!--Automatic injection of timed task components - 　　 <Context:component-scanBase-package= "XXX" /> 　　 <!--to start a timed task of annotation mode - 　　 <Task:annotation-driven/></Beans>

3. Quartz
Quartz is an open source, very rich timer framework, see: http://www.quartz-scheduler.org/.
Quartz can be used independently or in the spring framework, see: http://projects.spring.io/spring-framework/.

(1) Independent use of quartz (see Quartz official example):
Pom.xml:

<Dependencies> 　　 <Dependency> 　　　　 <groupId>Org.quartz-scheduler</groupId> 　　　　 <Artifactid>Quartz</Artifactid> 　　　　 <version>2.2.1</version> 　　 </Dependency> 　　 <Dependency> 　　　　 <groupId>Org.quartz-scheduler</groupId> 　　　　 <Artifactid>Quartz-jobs</Artifactid> 　　　　 <version>2.2.1</version> 　　 </Dependency></Dependencies>

Define timed tasks, Myjob.java:

 Public class Implements Job {  publicvoidthrows  jobexecutionexception {System.out.println ( New　　SimpleDateFormat ("Yyyy-mm-dd HH:mm:ss"). Format (new  Date ())); }}

Scheduling Scheduled Tasks, Myjobsheduler:

 Public classMyjobsheduler { Public Static voidMain (string[] args) {Try{jobdetail Job= Jobbuilder.newjob (MyJob.class). Withidentity ("MyJob"). build (); Trigger Trigger=Triggerbuilder.newtrigger (). Withidentity ("Trigger1", "group1")
. Withschedule (Simpleschedulebuilder.simpleschedule (). Withintervalinseconds (1). RepeatForever ())
. build (); Scheduler Scheduler=Stdschedulerfactory.getdefaultscheduler ();　　　　　　Scheduler.schedulejob (Job, trigger);　　　　　　Scheduler.start (); } Catch(schedulerexception e) {e.printstacktrace (); }}}

(2) Spring integrated quartz
such as: http://docs.spring.io/spring/docs/5.0.0.M4/spring-framework-reference/htmlsingle/#scheduling-quartz.

"Implementation Comparison"

Implementation method	Advantages	Disadvantages
JDK components	No need to introduce third-party dependencies, flexible control	Supports simple task scheduling only, does not support complex scheduled tasks such as date specified
Spring Task	Full functionality relative to JDK (simple or complex task scheduling with specified dates), support for annotations and configuration 2 ways	Spring 3.x and above are supported, see: Http://www.springframework.org/schema/task, and cannot flexibly control task start or stop.
Quartz	Open source, full-featured and powerful (complex task scheduling with simple or specified dates), can be used independently, or integrated with spring must introduce quartz dependencies in the project	Quartz dependencies must be introduced in the project.

"Summary of Usage"
1. The EE project
--We recommend using quartz without relying on the spring framework.
--Spring 3.x+ is introduced and spring task is recommended if only simple timed task control is required; otherwise, quartz is recommended.
-in particular, in the Spring Boot project, jdk,spring task or quartz can be flexibly selected on demand.

2. Non-EE project
--Simple scheduled task control, we recommend using the JDK implementation: java.util.concurrent.ScheduledThreadPoolExecutor; otherwise, quartz is recommended.

Attached:Linux crontab

In the Linux environment, you can use the CRONTAB program directly to achieve simple timing tasks, such as the timing of the full amount of backup MySQL database.
See: Https://wiki.archlinux.org/index.php/Cron_ (%e7%ae%80%e4%bd%93%e4%b8%ad%e6%96%87)

Reference
Several implementations of http://gong1208.iteye.com/blog/1773177 spring timed tasks
http://www.cnblogs.com/liuyitian/p/4108391.html Spring cron Expression
http://blog.csdn.net/ethanzhao/article/details/4406017 Linux crontab Command format with detailed examples

Java Timer Implementation Summary