How to correctly schedule this 5 minutes Spring Batch Job? Why is it starting immediatly instead of-CodePudding

I am working on a Spring Batch application and I am finding some difficulties trying to correctly schedule a job.

I will try to explain my problem in details. I have this class where my job was scheduled:

/**
 * This bean schedules and runs our Spring Batch job.
 */
@Component
@Profile("!test")
public class SpringBatchExampleJobLauncher {

    private static final Logger LOGGER = LoggerFactory.getLogger(SpringBatchExampleJobLauncher.class);

    @Autowired
    @Qualifier("launcher")
    private JobLauncher jobLauncher;
    
    @Autowired
    @Qualifier("updateNotaryDistrictsJob")
    private Job updateNotaryDistrictsJob;

    @Autowired
    @Qualifier("updateNotaryListInfoJob")
    private Job updateNotaryListInfoJob;
    
    @Scheduled(cron = "0 */5 * * * *")
    public void runUpdateNotaryDistrictsJob() {
        LOGGER.info("SCHEDULED run of updateNotaryDistrictsJob STARTED");
        Map<String, JobParameter> confMap = new HashMap<>();
        confMap.put("time", new JobParameter(System.currentTimeMillis()));
        JobParameters jobParameters = new JobParameters(confMap);
        try {
            jobLauncher.run(updateNotaryDistrictsJob, jobParameters);
        }catch (Exception ex){
            LOGGER.error(ex.getMessage());
        }

    }
    
}

As you can see on my runUpdateNotaryDistrictsJob() method I set this Spring CRON expression:

@Scheduled(cron = "0 */5 * * * *")

in order to start my updateNotaryDistrictsJob every 5 minuts.

The problem is that when I run my application in debug mode I can see that the job is immediatly performed (it stop on the first breackpoint). It seems that it is not waiting the 5 minutes set by the cron expression.

Why? What is wrong? How can I try to solve this issue?

Tnx

CodePudding user response：

The cron expression 0 */5 * * * * does not read as you expect. "It seems that it is not waiting the 5 minutes set by the cron expression.", this is not what the cron expression defines. The cron expression will run at second 0, every 5 minutes starting at minute 0, of every hour, which means that it will never wait 5 minutes after the service has started. As an example, if you started it at 10:22, it will run at 10:25.

If you really need it to wait 5 minutes after service has started, you should consider using @Scheduled(fixedRate = 5000, initialDelay = 5000).