Quartz Cron with Spring Framework

Quartz is an open source for job scheduling wich may be easily plugged in any working java project.

• Step 1

In the applicationContext.xml, add the job details (class and target method). Target method should be a public method without parameters.

<bean name="aBackgroundJob" class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean">
<property name="targetObject" class="net.slm.BackgroundWorkerClass"/>
<property name="targetMethod" value="methodToCallOnQuartzEvent"/>
<!-- This job maybe concurrent (default) or exclusive -->
<property name="concurrent" value="false"/>

 </bean>

• Step 2

Now, there are two ways to run this job using Quartz library, either a simple cron scheduled after server start and having a repeat interval (simpleTrigger) :

<bean id="dailyCronTrigger" class="org.springframework.scheduling.quartz.SimpleTriggerBean">
<property name="jobDetail" ref="aBackgroundJob"/>
<!-- 2 minutes after server starting -->
<property name="startDelay" value="120000"/>
<!-- repeat every 24 hours (1000*60*60*24)-->
<property name="repeatInterval" value="86400000"/>
 </bean>

The second option is to use quartz specific regular expressions to schedule fire time. Those regular expressions are explained in details here.

<bean id="dailyCronTrigger" class="org.springframework.scheduling.quartz.CronTriggerBean">
<property name="jobDetail" ref="aBackgroundJob"/>
<!-- run every day at 9:30 AM -->
<property name="cronExpression" value="0 30 9 * * ?"/>
<property name="concurrent" value="false"/>
 </bean>

• Step 3

To get those events fired, you must subscribe crons to a schedular:

<bean class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
<property name="triggers">
<list>
<ref bean="dailyCronTrigger" />
</list>
</property>
 </bean>

• Step 4

Some java code for the job.

package net.slm;

import java.util.Date;

public class BackgroundWorkerClass {

public void methodToCallOnQuartzEvent(){
System.out.println("Quartz job started at "+new Date());
//or do whatever you want
}

}

There are similar libraries here but I think that quartz is the richest.