Access Spring Batch Job definition

问题

I've got a Job description:

<job id="importJob" job-repository="jobRepository">
    <step id="importStep1" next="importStep2" parent="abstractImportStep">
        <tasklet ref="importJobBean" />
    </step>
    <step id="importStep2" next="importStep3" parent="abstractImportStep">
        <tasklet ref="importJobBean" />
    </step>
    <step id="importStep3" next="importStep4" parent="abstractImportStep">
        <tasklet ref="importJobBean" />
    </step>
    <step id="importStep4" next="importStepFinish" parent="abstractImportStep">
        <tasklet ref="importJobBean" />
    </step>
    <step id="importStepFinish">
        <tasklet ref="importJobBean" />
    </step>
</job>

I want to know how many steps were defined in "importJob" (5 in this case). Looks like Job and JobInstance api has nothing relevant. Is this possible at all?

回答1:

You have options

JobExplorer

The cleanest way to read meta data about your Job is through JobExplorer:

public interface JobExplorer {

    List<JobInstance> getJobInstances(String jobName, int start, int count);

    JobExecution getJobExecution(Long executionId);

    StepExecution getStepExecution(Long jobExecutionId, Long stepExecutionId);

    JobInstance getJobInstance(Long instanceId);

    List<JobExecution> getJobExecutions(JobInstance jobInstance);

    Set<JobExecution> findRunningJobExecutions(String jobName);
}

JobExecution

But you can also get it by simply looking at JobExecution:

// Returns the step executions that were registered
public Collection<StepExecution> getStepExecutions()

JobLauncher returns you a JobExecution when you launch the job:

public interface JobLauncher {

    public JobExecution run(Job job, JobParameters jobParameters) 
                throws JobExecutionAlreadyRunningException, JobRestartException;
}

Or you can get it via JobExecutionListener

public interface JobExecutionListener {

    void beforeJob(JobExecution jobExecution);

    void afterJob(JobExecution jobExecution);
}

There are other ways to obtain it, but the above two should suffice.

EDIT to answer the comment:

In case you'd like to get a metadata regardless of whether or not the step was executed, there is a convenience method getStepNames which is defined by the AbstractJob and is implemented (e.g.) in SimpleJob as:

/**
 * Convenience method for clients to inspect the steps for this job.
 * 
 * @return the step names for this job
 */
 public Collection<String> getStepNames() {
     List<String> names = new ArrayList<String>();
     for (Step step : steps) {
         names.add(step.getName());
     }
     return names;
 }

来源：https://stackoverflow.com/questions/7808867/access-spring-batch-job-definition

标签

Spring

spring-batch