+++ title = “Use Spring Boot Starter” weight = 3 chapter = true +++

ElasticJob-Lite provides a customized Spring Boot Starter, which can be used in conjunction with Spring Boot. Developers are free from configuring CoordinatorRegistryCenter, JobBootstrap by using ElasticJob Spring Boot Starter. What developers need to solve distributed scheduling problem are job implementations with a little configuration.

Job configuration

Implements ElasticJob

Job implementation is similar to other usage of ElasticJob. The difference is that jobs will be registered into the Spring IoC container.

Thread-Safety Issue

Bean is singleton by default. Consider setting Bean Scope to prototype if the instance of ElasticJob would be used by more than a JobBootstrap.

@Component
public class SpringBootDataflowJob implements DataflowJob<Foo> {
    
    @Override
    public List<Foo> fetchData(final ShardingContext shardingContext) {
        // fetch data
    }
    
    @Override
    public void processData(final ShardingContext shardingContext, final List<Foo> data) {
        // process data
    }
}

Configure CoordinateRegistryCenter and Jobs

Configure the Zookeeper which will be used by ElasticJob via configuration files.

elasticjob.jobs is a Map. Using key as job name. Specific job type and configuration in value. The Starter will create instances of OneOffJobBootstrap or ScheduleJobBootstrap and register them into the Spring IoC container automatically.

Configuration reference:

elasticjob:
  regCenter:
    serverLists: localhost:6181
    namespace: elasticjob-lite-springboot
  jobs:
    dataflowJob:
      elasticJobClass: org.apache.shardingsphere.elasticjob.dataflow.job.DataflowJob
      cron: 0/5 * * * * ?
      shardingTotalCount: 3
      shardingItemParameters: 0=Beijing,1=Shanghai,2=Guangzhou
    scriptJob:
      elasticJobType: SCRIPT
      cron: 0/10 * * * * ?
      shardingTotalCount: 3
      props:
        script.command.line: "echo SCRIPT Job: "

Job Start

Schedule Job

Just start Spring Boot Starter directly. The schedule jobs will startup when the Spring Boot Application is started.

One-off Job

When to execute OneOffJob is up to you. Developers can inject the OneOffJobBootstrap bean into where they plan to invoke. Trigger the job by invoking execute() method manually.

About @DependsOn Annotation

JobBootstraps are created by the Starter dynamically. It's unable to inject the JobBootstrap beans if the beans which depends on JobBootstrap were instantiated earlier than the instantiation of JobBootstrap.

Developers can also retrieve JobBootstrap beans by ApplicationContext.

The bean name of OneOffJobBootstrap is specified by property “jobBootstrapBeanName”, Please refer to Spring Boot Starter Configuration.

@RestController
@DependsOn("ElasticJobLiteAutoConfiguration")
public class OneOffJobController {
    
    @Resource(name = "manualScriptJobOneOffJobBootstrap")
    private OneOffJobBootstrap manualScriptJob;
    
    @GetMapping("/execute")
    public String executeOneOffJob() {
        manualScriptJob.execute();
        return "{\"msg\":\"OK\"}";
    }
}