Quartz (1): Web Applications

This is how I added a Quartz job to my webapp:

1. Implement a simple Quartz job
2. Create a configuration file that would start this job
3. Create a Quarty properties file
4. Add the Quartz context listener to the webapp to auto-start the scheduler

1. Implement a simple Quartz job (example/ExampleJob.java):
   

   This Job just prints the value of the job parameter “message” to the console.package example;
    
   import org.quartz.Job;
   import JobExecutionContext;
    
   public class ExampleJob implements Job {
    
       public void execute(JobExecutionContext context) {
           System.out.println(context.getJobDetail().getJobDataMap().get("message"));
       }
    
   }
   

2. Create a configuration file that would start this job (resources/quartz/jobs.xml):
   

   The job is triggered 4 times (3 repreats) in a 10 seconds interval.<?xml version="1.0" encoding="UTF-8"?>
   <quartz xmlns="http://www.opensymphony.com/quartz/JobSchedulingData"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.opensymphony.com/quartz/JobSchedulingData
       http://www.opensymphony.com/quartz/xml/job_scheduling_data_1_5.xsd"
       version="1.5">
     <job>
       <job-detail>
         <name>ExampleJob</name>
         <group>examples</group>
         <job-class>example.ExampleJob</job-class>
         <job-data-map>
           <entry>
             <key>message</key>
             <value>Hello World</value>
           </entry>
         </job-data-map>
       </job-detail>
       <trigger>
         <simple>
           <name>ExampleTrigger</name>
           <group>examples</group>
           <job-name>ExampleJob</job-name>
           <job-group>examples</job-group>
           <repeat-count>3</repeat-count>
           <repeat-interval>10000</repeat-interval>
         </simple>
       </trigger>
     </job>
   </quartz>
   

Create a Quarty properties file (resources/quartz/quartz.properties):# General properties:
org.quartz.scheduler.instanceName=MACHwbQuartzScheduler
org.quartz.scheduler.instanceId=AUTO
# Thread pool:
org.quartz.threadPool.class=org.quartz.simpl.SimpleThreadPool
org.quartz.threadPool.threadCount=1
# Load jobs from XML file:
org.quartz.plugin.jobInitializer.class=org.quartz.plugins.xml.JobInitializationPlugin
org.quartz.plugin.jobInitializer.fileName=resources/quartz/jobs.xml
org.quartz.plugin.jobInitializer.failOnFileNotFound=true

Add the Quartz context listener to the webapp to auto-start the scheduler (WEB-INF/web.xml): <web-app>
  [...]
  <context-param>
    <param-name>config-file</param-name>
    <param-value>resources/quartz/quartz.properties</param-value>
    <description>Location of the Quartz configuration file</description>
  </context-param>
  [...]
  <listener>
    <listener-class>org.quartz.ee.servlet.QuartzInitializerListener</listener-class>
  </listener>
  [...]
</web-app>

…but it is easier with Spring.