Quartz Scheduler + Spring: How to get initial cron expression from JobStore when creating the Trigger?

Question

Using JobStoreTX, how can I get the cron expression of trigger which's already in the database?

I tried this, but won't work.

    @Bean
    public CronTriggerFactoryBean cancelamentoTrigger(@Qualifier("cancelamentoJobDetail") JobDetail job, JobStore jobStore) throws JobPersistenceException {
        CronTriggerFactoryBean trigger = new CronTriggerFactoryBean();
        trigger.setJobDetail(job);

        TriggerKey cancelamentoTrigger = new TriggerKey("cancelamentoTrigger");
        if (jobStore.checkExists(cancelamentoTrigger)) {
            trigger.setCronExpression(((CronTrigger) scheduler.getTrigger(cancelamentoTrigger)).getCronExpression());
        } else {
            trigger.setCronExpression("0/30 0/1 * 1/1 * ? *");
        }
        
        return trigger;
    }