无法将 JobParameters 值传递给 Spring Batch 中的 tasklet答案

【问题标题】：Unable to pass the JobParameters Value to the tasklet in Spring Batch无法将 JobParameters 值传递给 Spring Batch 中的 tasklet
【发布时间】：2018-12-13 17:44:25
【问题描述】：

我已经关注了链接：Pass JobParameters and ExecutionContext to @Bean Tasklet?，但在将jobParameters 值传递给tasklet 时仍然遇到问题。

我开发了如下代码：

JobConfiguration.java

@Component
public class JobConfiguration implements ApplicationContextAware{

    @Autowired
    private JobBuilderFactory jobBuilderFactory;

    @Autowired
    private StepBuilderFactory stepBuilderFactory;

    @Autowired
    private JobExplorer jobExplorer;

    @Autowired
    private JobRepository jobRepository;

    @Autowired
    private JobRegistry jobRegistry;

    private ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }

    @Bean
    @StepScope
    public Tasklet tasklet(@Value("#{jobParameters['name']}") String name) {
        System.out.println("NAME VALUE  = "+name);
        return (contribution, chunkContext) -> {
            System.out.println(String.format("The job run for %s", name));
            return RepeatStatus.FINISHED;
        };
    }

    @Bean
    public Job job() {
        return jobBuilderFactory.get("job")
                .start(stepBuilderFactory.get("step1")
                        .tasklet(tasklet(null))
                        .build())
                .build();
    }
}

JobLaunchingController.java

@RestController
public class JobLaunchingController {
    @Autowired
    private JobLauncher jobLauncher;

    @Autowired
    private Job job;

    @PostMapping("/")
    @ResponseStatus(value = HttpStatus.ACCEPTED)
    public void launch(@RequestParam("name") String name) throws JobExecutionAlreadyRunningException, JobRestartException, JobInstanceAlreadyCompleteException, JobParametersInvalidException {
        JobParameters jobParameters = new JobParametersBuilder()
                .addString("name", name)
                .toJobParameters();
        JobExecution jobExecution = this.jobLauncher.run(job, jobParameters);
        System.out.println("STATUS = "+jobExecution.getStatus());
    }
}

日志：

2018-12-13 23:09:35.930  INFO 20004 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2018-12-13 23:09:35.930  INFO 20004 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2018-12-13 23:09:35.938  INFO 20004 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 8 ms
2018-12-13 23:09:55.046  INFO 20004 --- [nio-8080-exec-1] o.s.b.c.l.support.SimpleJobLauncher      : Job: [SimpleJob: [name=job]] launched with the following parameters: [{name=foo}]
2018-12-13 23:09:55.414  INFO 20004 --- [nio-8080-exec-1] o.s.batch.core.job.SimpleStepHandler     : Executing step: [step1]
The job run for null
2018-12-13 23:09:55.672  INFO 20004 --- [nio-8080-exec-1] o.s.b.c.l.support.SimpleJobLauncher      : Job: [SimpleJob: [name=job]] completed with the following parameters: [{name=foo}] and the following status: [COMPLETED]
STATUS = COMPLETED

StartingAJobApplication.java

@SpringBootApplication
@EnableBatchProcessing
public class StartingAJobApplication {

    public static void main(String[] args) {
        SpringApplication.run(StartingAJobApplication.class, args);
    }
}

卷曲：

curl --data 'name=foo' localhost:8080

【问题讨论】：

标签： spring spring-batch spring-batch-tasklet

【解决方案1】：

这很正常，因为您自己将 tasklet 传递给作业，并且它的参数为空。

要使用@StepScop 功能，您需要使用创建的bean spring

    @Bean
    public Job job(Tasklet tasklet) {
        return jobBuilderFactory.get("job")
                .start(stepBuilderFactory.get("step1")
                        .tasklet(tasklet)
                        .build())
                .build();
    }

【讨论】：

bean是stepscoped，所以它的创建不会和只调用函数一样，你测试过我提供给你的解决方案吗

【解决方案2】：

当你实现“execute”方法时，你有 SetpContribution 和 ChunkContext 作为参数。你必须使用 ChunkContext 来获取 jobParameter。

  @Override
  public RepeatStatus execute(StepContribution stepContribution, ChunkContext chunkContext) throws Exception {

    JobParameters jobParameters = chunkContext.getStepContext().getStepExecution().getJobParameters();

      ...
}

【讨论】：