Jan Materne: Java-Cron-Jobs with Spring and Quartz

We have several Jobs running the business. At the moment they are implemented as Spring-driven TimerTasks. But the next job should be run only nightly and a cron-like configuration syntax would be fine.

So I found Quartz and had to integrate that. For getting familiar with Quartz+Spring I wrote a small proof of concept.

The job implementation is just a POJO with a public void method. It should not throw any exception. The bean can be configured via usual Spring DI:

public class MyBean {

private String message;

public void doIt() {
System.out.println("Hello World: " + message);
}

public String getMessage() {
return message;
}

public void setMessage(String message) {
this.message = message;
}

}

So fine. But how to test? For this PoC a very simple test is ok – just wait for some Quartz run and check the output manually:

import static org.junit.Assert.assertNotNull;

import org.junit.AfterClass;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class QuartzTest {

@Test
public void context() {
System.out.println("Starting Spring and within that: Quartz");
ApplicationContext ctx = new ClassPathXmlApplicationContext("spring-config.xml");
assertNotNull(ctx);
}

@AfterClass public static void sleep() throws InterruptedException {
System.out.println("Wait for job output");
Thread.sleep(8000);
System.out.println("ready");
}
}

When using Spring, we have to provide the configuration.
First I define my Job-bean

<bean id="myBean">
<property name="message" value="TEST" />
</bean>

After that I configure Quartz:

<bean id="scheduler"
class="org.springframework.scheduling.quartz.SchedulerFactoryBean"
scope="singleton">
<property name="triggers">
<list>
<!-- trigger list -->
<ref bean="job1" />
</list>
</property>
</bean>

The binding between job and Quartz is done via a configured CronTriggerBean.

<bean id="job1">
<property name="cronExpression" value="0/2 * * * * ?" />
<property name="jobDetail">
<bean>
<property name="name" value="job1" />
<property name="group" value="nightlyJobs" />
<!-- Delegieren auf unsere Bean und unsere Methode -->
<property name="targetObject" ref="myBean" />
<property name="targetMethod" value="doIt" />
<property name="concurrent" value="false" />
</bean>
</property>
</bean>

This CronTriggerBean defines two values:
1. cronExpression specifies when to run the job. An explanation about that syntax can be found at http://www.quartz-scheduler.org/documentation/quartz-1.x/tutorials/crontrigger.
2. jobDetail specifies a JavaBean with information about the job. But we dont have to write this Bean, we just can configure the generic one from Spring:
- name and group for controlling the execution via control interfaces
- targetObject and targetMethod for the delegation to our JobBean
- specify if this job should run in concurrent mode (where concurrent means in one VM!)

Building this sample with Maven is easy. You’ll need just following dependencies:

• org.springframework::spring-core::3.0.5.RELEASE
• org.springframework::spring-context::3.0.5.RELEASE
• org.springframework::spring-context-support::3.0.5.RELEASE
• org.springframework::spring-tx::3.0.5.RELEASE
• org.quartz-scheduler::quartz::1.8.5
• junit::junit::4.9::{scope=test}

As far as I read you can’t use Quartz 2.x because Spring 3 doesnt support that. But I havent tried it.

When running you’ll get this output:

Starting Spring and within that: Quartz
... logs from Spring
... infos from SLF4J
INFO: Starting Quartz Scheduler now
Wait for job output
Hello World: TEST
Hello World: TEST
Hello World: TEST
Hello World: TEST
Hello World: TEST
ready