Spring Step Scoped bean 不遵守 @Order 注释

Question

When I create 2 beans with @StepScope and apply @Order then the order for both beans still gets resolved to Ordered.LOWEST_PRECEDENCE when trying to autowire them as a List.

@Bean
@Order(1)
@StepScope
public MyBean bean1(
    return new MyBean("1");
}

@Bean
@Order(2)
@StepScope
public MyBean bean2(
    return new MyBean("2");
}

Looking in OrderComparator I see the beans are resolved to a source of ScopedProxyFactoryBean which returns a null order value. Wondering if Im doing something wrong here as I would expect the ordering to work correctly.

So the aim in to autowire an ordered list into another bean eg

@Component   
public class OuterBean {
  private List<MyBean> beans;
  public OuterBean(List<MyBean> beans) {
    this.beans = beans;
  }
}

And I would expect the list to contain {bean1,bean2}

Answer 1

Step scoped beans need to be used in the scope of a running step. Here is an example:

import java.util.List;

import org.springframework.batch.core.Job;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepScope;
import org.springframework.batch.core.step.tasklet.Tasklet;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.annotation.Order;

@Configuration
public class MyJob {

    @Bean
    @Order(1)
    @StepScope
    public MyBean bean1() {
        return new MyBean("1");
    }

    @Bean
    @Order(2)
    @StepScope
    public MyBean bean2() {
        return new MyBean("2");
    }

    @Bean
    public OuterBean outerBean(List<MyBean> beans) {
        return new OuterBean(beans);
    }

    @Bean
    public Tasklet tasklet(OuterBean outerBean) {
        return (contribution, chunkContext) -> {
            outerBean.sayHello();
            return RepeatStatus.FINISHED;
        };
    }

    @Bean
    public Job job(JobBuilderFactory jobs, StepBuilderFactory steps) {
        return jobs.get("job")
                .start(steps.get("step")
                        .tasklet(tasklet(null))
                        .build())
                .build();
    }

}

The complete code can be found here . This example prints:

bean = 1
bean = 2

which means step scoped beans have been injected in the right order.