4 Ways to Schedule Tasks in Spring 3 _ @Scheduled Example _ How to Do in JAVA

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In previous post, we learned about 2 ways to use timer tasks in spring 3 framework.

Spring provides excellent support for scheduling jobs based on cron expression

also. This scheduling is possible with use of @Scheduled annotation. According to

spring documentation:

Spring 3.0 also adds annotation support for both task scheduling and asynchronous

method execution. The @Scheduled annotation can be added to a method along with

trigger metadata.

In this post, I will show the means to use this feature in 4 different ways.

Sections in this post:

Explaining @Scheduled annotation

Task scheduling using fixed delay attribute in @Scheduled annotation

Task scheduling using cron expression in @Scheduled annotation

Task scheduling using cron expression from properties file and

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FRAMEWORKS, SPRING 3

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4 ways to schedule tasks in Spring 3 : @Scheduledexample23 APRIL, 2013 | LOKESH GUPTA+ 26 COMMENTS

How to do in JAVA



@Scheduled annotation

Task scheduling using cron expression configured in context

configuration

Sourcecode download link

Explaining @Scheduled annotation

This annotation is used for task scheduling. The trigger information needs to be

provided along with this annotation. You can use the properties

fixedDelay/fixedRate/cron to provide the triggering information.

1. fixedRate makes Spring run the task on periodic intervals even if the last invocation

may be still running.

2. fixedDelay specifically controls the next execution time when the last execution

finishes.

3. cron is a feature originating from Unix cron utility and has various options based on

your requirements.

Example usage can be as below:

@Scheduled(fixedDelay =30000)

public void demoServiceMethod () {... }

@Scheduled(fixedRate=30000)


@Scheduled(cron="0 0 * * * *")


To use @Scheduled in your spring application, you must first define below xml

namespace and schema location definition in your application-config.xml file.

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xmlns:task="http://www.springframework.org/schema/task" http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.0.xsd

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Above additions are necessary because we will be using annotation based

configurations. Now add below definition to enable annotations.

Next step is to create a class and a method inside the class like below:

Using @Scheduled annotation would in turn make Spring container understand that the

method underneath this annotation would run as a job. Remember that the methods

annotated with @Scheduled should not have parameters passed to them. They should

not return any values too. If you want the external objects to be used within your

@Scheduled methods, you should inject them into the DemoService class using

autowiring rather than passing them as parameters to the @Scheduled methods.

Method 1) Task scheduling using fixed delay attribute in@Scheduled annotation

In this method, fixedDelay attribute is used with @Scheduled annotation. Alternatively,

fixedRate can also be used.

A sample class will look like this:

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public class DemoService{ @Scheduled(cron="*/5 * * * * ?") public void demoServiceMethod() { System.out.println("Method executed at every 5 seconds. Current time is :: " }}

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package com.howtodoinjava.service; import java.util.Date;import org.springframework.scheduling.annotation.Scheduled; public class DemoServiceBasicUsageFixedDelay{ @Scheduled(fixedDelay = 5000) //@Scheduled(fixedRate = 5000) public void demoServiceMethod() { System.out.println("Method executed at every 5 seconds. Current time is :: " }}

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And application configuration will look like this:

Method 2) Task scheduling using cron expression in@Scheduled annotation

In this method, cron attribute is used with @Scheduled annotation. Value of this

attribute must be a cron expression.



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< ?xml version="1.0" encoding="UTF-8"?>



Method 3) Task scheduling using cron expression fromproperties file

In this method, cron attribute is used with @Scheduled annotation. Value of this

attribute must be a cron expression as in previous method, BUT, this cron expression

will be defined in a properties file and key of related property will be used in @Scheduled

annotation.

This will decouple the cron expression from source code, thus making changes easy.



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http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task-3.0.xsd">



Method 4) Task scheduling using cron expressionconfigured in context configuration

In this method, cron expression is configured in properties file, and job scheduling is

configured in configuration file using property key for cron expression. Major change is

that you do not need to use @Scheduled annotation on any method. Method

configuration is also done in application configuration file.



141516



Bio Latest Posts

Download sourcecode for above examples using below link.

Download Sourcecode

Let me know if I am missing anything.

Happy Learning !!

Reference:

http://forum.springsource.org/showthread.php?83053-Feature-Scheduled-with-Value-

cron-expression

Lokesh GuptaSenior Analyst at Bank of America

I love to discuss things and thats exactly why I am here. In java, I have

around 7 Yrs of experience, which has only increased my hunger for

learning more. In this blog, i will be writing on different topics

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occasionally, and i would really love to engage in some meaningful

serious discussions with you folks. I hope to hear from all you lovely

people. Follow me on Google +

Related posts:

1. 2 ways to execute timer tasks in spring 3

2. Spring 3.2.5.RELEASE and Hibernate 4 Integration Example Tutorial

3. Spring bean autowire byType

4. Spring bean scopes

5. Spring bean autowire byName

26 THOUGHTS ON 4 WAYS TO SCHEDULE TASKS IN SPRING 3 : @SCHEDULED EXAMPLE

19 DECEMBER, 2013 AT 2:12 AM

excellent guide. very helpful

6 DECEMBER, 2013 AT 1:18 AM

This is exactly what I was looking for. Thanks!

13 NOVEMBER, 2013 AT 10:56 AM

Thanx mate. It was really helpful

29 OCTOBER, 2013 AT 5:26 AM

i am trying to use @Scheduled(fixedRate=86400000) to schedule it every 24

hrs.

what if my server (tomcat) is shutdown (for example another deployment), will

it run in every 24hrs.

@SCHEDULED ANNOTATION SPRING 3

Hector

Justin Johnson

shihan iqbal

DINESH MAHARJAN




NO. It will not.


nice tutorial.. thank you for sharing

6 OCTOBER, 2013 AT 5:08 PM

Hi, Lokesh. Thank you for sharing!

I have one more question: which are the best ways to combine these solutions

with the @Async annotation?

Thank you!


@Async annotation helps in asynchronous processing, means you do

not want to wait for completion of task. Use it when you have a valid

usecase. Putting @Async annotation is enough.


Youre completely right, Lokesh! Thank you for your quick

response.


Hi Lokesh,

I am new to spring..can you please tell me how to implement above scheduler

in my application..how to pass parameter to a method if I schedule it.


If I am understanding correctly, you want to schedule based on user

Lokesh Gupta

Ramesh

Almir Campos

Lokesh Gupta

Almir Campos

bharat

Lokesh Gupta



preferences which multiple users can have differently, and schedule

information stored in database. If it is your case, use something else e.g.

quartz.


Hi Lokesh,

I am using config in my application like below

I want to modify fixed-delay parameter on the fly from a JSP page

, is there a way to get and set fixed-delay programatically and

modify it on the fly?

Thanks,

Pankaj


Try to work in this direction:

http://stackoverflow.com/questions/15250928/how-to-

change-springs-scheduled-fixeddelay-at-runtime


Thanks Lokesh , will try out this.


I am facing sudden stop in execution of scheduled task and there are no

exception no log even in server.

can any body please suggest me what to do..


Thats strange. Try putting whole code in scheduler inside try-catch.

Catch Exception class in catch block. Set logging level debug.

Anybody, any idea??

Pankaj

Lokesh Gupta

Pankaj

Atul Sharma

Lokesh Gupta



18 SEPTEMBER, 2013 AT 9:00 PM

Hi,

I am planning to write a web-app to create appointments with teachers.

Student should be able to create an appointment with teacher at a time. How

can we do this using Spring.


Hi,

I referred to your Spring MVC blog and it was very useful to me. I am planning

to write an application using java to schedule appointment with teachers.

Students can fix appointment with teachers by specifying the time. Student

can fix one slot with one teacher at a time. Once the time is fixed, the

application should not allow the student or the teacher to book the slot to

others.

How can I use the Spring scheduler to achieve this? Also can Spring take date

and time values to set up an appointment? Please let me know how to do this

in spring.

Regards,

Pradeep


Why you need Spring scheduler for this. Schedulers are for executing a

repeating task in certain interval. You just need to store appointment

details in database using simple MVC and validate against it in other

places.

Am i missing anything?


But If I store the appointment details in the DB, I need to do a lot

of validation so that the student cannot crete another

appointment with someone at the same time, the teacher cannot

Pradeep

Pradeep

Lokesh Gupta

Pradeep



have appointment with other student at the same time.. etc. Is

there any better way to do this?


Why lots of validations? You can reduce lots of logic by

creating well-thought SELECT queries and unique key

constraints.


Got it!! having a many to many relationship by

having a join table ad putting the constraints I can

get there. Cool.

Any idea of how to do a UI for the same. Like

integrating the server with outlook or gmail or

custom Calendar UI. PLease let me know.


Sorry on this. Never worked on something like this.

24 JULY, 2013 AT 4:45 PM

Its a great article.to the point!

18 JULY, 2013 AT 4:26 PM

Thanks for sharing

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Lokesh Gupta

Pradeep

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4 Ways to Schedule Tasks in Spring 3 _ @Scheduled Example _ How to Do in JAVA