Spring批处理在tasklet中执行动态生成的步骤

Question

第2步。根据在步骤1中创建的对象列表中有多少项创建步骤列表。

第三步。尝试执行步骤2中创建的步骤列表中的步骤。

下面在executeDynamicStepsTasklet（）中执行x个步骤。虽然代码运行时没有任何错误，但它似乎没有做任何事情。我在那个方法中的内容看起来正确吗？

@Configuration
public class ExportMasterListCsvJobConfig {

public static final String JOB_NAME = "exportMasterListCsv";
@Autowired
public JobBuilderFactory jobBuilderFactory;

@Autowired
public StepBuilderFactory stepBuilderFactory;

@Value("${exportMasterListCsv.generateMasterListRows.chunkSize}") 
public int chunkSize;

@Value("${exportMasterListCsv.generateMasterListRows.masterListSql}") 
public String masterListSql;

@Autowired
public DataSource onlineStagingDb;

@Value("${out.dir}") 
public String outDir;

@Value("${exportMasterListCsv.generatePromoStartDateEndDateGroupings.promoStartDateEndDateSql}") 
private String promoStartDateEndDateSql;


private List<DivisionIdPromoCompStartDtEndDtGrouping> divisionIdPromoCompStartDtEndDtGrouping;

private List<Step> dynamicSteps = Collections.synchronizedList(new ArrayList<Step>()) ;


@Bean
public Job exportMasterListCsvJob(
        @Qualifier("createJobDatesStep") Step createJobDatesStep,
        @Qualifier("createDynamicStepsStep") Step createDynamicStepsStep,
        @Qualifier("executeDynamicStepsStep") Step executeDynamicStepsStep) {

    return jobBuilderFactory.get(JOB_NAME)
            .flow(createJobDatesStep)
            .next(createDynamicStepsStep)
            .next(executeDynamicStepsStep)
            .end().build();
}   


@Bean
public Step executeDynamicStepsStep(
        @Qualifier("executeDynamicStepsTasklet")  Tasklet executeDynamicStepsTasklet) {

    return  stepBuilderFactory
                .get("executeDynamicStepsStep")
                .tasklet(executeDynamicStepsTasklet)
                .build();               
}

@Bean
public Tasklet executeDynamicStepsTasklet() {

    return new Tasklet() {

        @Override
        public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
            FlowStep flowStep = new FlowStep(createParallelFlow());
            SimpleJobBuilder jobBuilder = jobBuilderFactory.get("myNewJob").start(flowStep);
            return RepeatStatus.FINISHED;
        }
    };
}

public Flow createParallelFlow() {
    SimpleAsyncTaskExecutor taskExecutor = new SimpleAsyncTaskExecutor();
    taskExecutor.setConcurrencyLimit(1); 

    List<Flow> flows = dynamicSteps.stream()
            .map(step -> new FlowBuilder<Flow>("flow_" + step.getName()).start(step).build())
            .collect(Collectors.toList());

    return new FlowBuilder<SimpleFlow>("parallelStepsFlow")
            .split(taskExecutor)
            .add(flows.toArray(new Flow[flows.size()]))
            .build();
}

@Bean

public Step createDynamicStepsStep(
        @Qualifier("createDynamicStepsTasklet")  Tasklet createDynamicStepsTasklet) {

    return  stepBuilderFactory
                .get("createDynamicStepsStep")
                .tasklet(createDynamicStepsTasklet)
                .build();               
}   

@Bean
@JobScope
public Tasklet createDynamicStepsTasklet() {

    return new Tasklet() {

        @Override
        public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws Exception {
            for (DivisionIdPromoCompStartDtEndDtGrouping grp: divisionIdPromoCompStartDtEndDtGrouping){

                System.err.println("grp: " + grp);

                String stepName = "stp_" + grp;

                String fileName = grp + FlatFileConstants.EXTENSION_CSV;

                Step dynamicStep = 
                        stepBuilderFactory.get(stepName)
                        .<MasterList,MasterList> chunk(10)
                        .reader(queryStagingDbReader(
                                grp.getDivisionId(), 
                                grp.getRpmPromoCompDetailStartDate(), 
                                grp.getRpmPromoCompDetailEndDate()))
                        .writer(masterListFileWriter(fileName))                                
                        .build(); 

                dynamicSteps.add(dynamicStep);

            } 
            System.err.println("createDynamicStepsTasklet dynamicSteps: " + dynamicSteps);
            return RepeatStatus.FINISHED;
        }
    };
}


public FlatFileItemWriter<MasterList> masterListFileWriter(String fileName) {
    FlatFileItemWriter<MasterList> writer = new FlatFileItemWriter<>();
    writer.setResource(new FileSystemResource(new File(outDir, fileName )));
    writer.setHeaderCallback(masterListFlatFileHeaderCallback());
    writer.setLineAggregator(masterListFormatterLineAggregator());
    return writer;
}

Answer 1

这样不行。您的Tasklet只是创建一个作业，第一步是FlowStep。使用jobBuilderfactory只需创建作业。它不会发射它。方法名“start”可能会产生误导，因为它只定义了第一步。但它不会启动作业。

一旦作业启动，就不能更改其结构（其步骤和子步骤）。因此，不可能根据步骤1中计算的内容来配置步骤2中的flowstep。（当然，您可以在springbatch结构的更深处进行一些黑客操作，并直接修改bean，等等……但是您不想这样做）。

我建议您使用一种带有适当的postConstruct方法的“SetupBean”，该方法被注入到配置作业的类中。这个“SetupBean”负责计算正在处理的对象列表。

@Component
public class SetUpBean {

  private List<Object> myObjects;

  @PostConstruct
  public afterPropertiesSet() {
    myObjects = ...;
  }

  public List<Object> getMyObjects() {
   return myObjects;
  }
}

@Configuration
public class JobConfiguration {

   @Autowired
   private JobBuilderFactory jobBuilderFactory;

   @Autowired
   private StepBuilderFactory stepBuilderFactory;

   @Autowired
   private SetUpBean setup;

   ... 
}