Altering Quartz Job Schedule

问题:

I'm looking into scheduling my application with Quartz, but in all cases, the job trigger seems to be a one-time activity, and changes to the trigger need the application to be re-deployed to take effect.
Is there any way I can have the job trigger check for changes to the job schedule without having to redeploy the code?
Thanks,

回答1:

1. Trap some user-driven event, like updating a text value, for example a cron-string to schedule a job
2. Locate and unschedule/delete the old job and trigger.

3. Schedule the job again, using the new trigger.

   public static <T> T scheduleCronJob(Class<T> clazz, String cronString, String uid){     try{                     if(cronString == null){             throw new CronStringConfigurationException();         }          String jobGroupName = "cronJobsGroup";         String jobName = "cronJob" + uid;         String triggerGroupName = "cronTriggers";         String triggerName = "triggerFor" + uid;          JobDetail jobDetail = new JobDetail(jobName, jobGroupName, clazz);          CronTrigger trigger = new CronTrigger(                 triggerName, triggerGroupName,                  jobName, jobGroupName,                  cronString);          JobDataMap jobDataMap = new JobDataMap();         jobDetail.setJobDataMap(jobDataMap);          getScheduler().scheduleJob(jobDetail, trigger);     } catch(Exception e){     // print error message, throw stack trace     }     return null; }  public static void reloadCronJob(Class clazz, String cronString, String uid) throws SystemException, ParseException, SchedulerException,      CronStringConfigurationException, PortalException{     // locate the job      String jobGroupName = "cronJobs";     String jobName = "jobFor" + uid;      if(cronString == null){         throw new CronStringConfigurationException();     }      JobDetail jobDetail = null;     Class<?> jobClass = null;      // remove the old job/trigger if it exists     try{         jobDetail = scheduler.getJobDetail(jobName, jobGroupName);         if(jobDetail != null){             jobClass = jobDetail.getJobClass();         }         scheduler.deleteJob(jobName, jobGroupName);     } catch(Exception e){         e.printStackTrace();     }      if(jobClass == null){         jobClass = clazz;     }      // create a new trigger     scheduleCronJob(jobClass, expandoColumnName, uid);      System.out.println("(re)scheduled job " + jobName + " using new cron string " + cronString); } 

文章来源: Altering Quartz Job Schedule