Spring Boot Cron Expression Generator

Enable scheduling first

@Scheduled does nothing on its own. Add @EnableScheduling to your main class or a configuration class, or the annotation is silently ignored:

@SpringBootApplication
@EnableScheduling
public class MyApp { ... }

Set timezone per task

Available from Spring 5.3+:

@Scheduled(cron = "0 0 9 * * MON-FRI",
           zone = "Europe/Madrid")
public void morningTask() { ... }

Use properties, not hardcoded values

Hardcoding cron expressions in annotations makes them impossible to change without redeployment. Use ${property.name} so you can change the schedule via application.properties or environment variables. See the Spring @Scheduled Javadoc.

# application.properties
app.cron.digest=0 0 9 * * MON-FRI

# application.yml
app:
  cron:
    digest: "0 0 9 * * MON-FRI"

@Scheduled(cron = "${app.cron.digest}", zone = "Europe/Madrid")
public void sendDigest() { ... }

Disable a scheduled task via properties

Set the cron value to - to disable a scheduled task without removing the annotation. Useful for disabling a job in specific environments:

# application-dev.properties
app.cron.digest=-   # disabled in dev

@Scheduled(cron = "${app.cron.digest:-}")
public void sendDigest() { ... }

The :- syntax sets - as the default value if the property is not defined.

@Scheduled methods must return void

A scheduled method's return value is always ignored. Methods must also take no arguments - Spring has nothing to pass in.

Spring Batch scheduled jobs

For Spring Batch, trigger a JobLauncher from a @Scheduled method. Same cron syntax applies - 6 fields, seconds first.