Java – spring batch use different transaction-manager between job-repository and actual tasks

javaspringspring-batch

I am using Spring Batch using 2 (maybe more, assume 2 for simplicity) databases.
One for storing all the job datas(all the BATCH_* tables). The other for actually running my business logic data.
There are some things I dont quite understand.

When I declared my JobRepository I have already specified my TransactionManager, why do I have to do it again on my tasklet?(I am not using the default name on purpose)
I am currently giving tasklet the same TrasactionManager as my JobRepository which is manages different connections from what I am doing inside my steps. Does that mean I have do my own transaction management inside my writer or reader?
If #2 is true, the "What If" in How does Spring Batch transaction management work? will be a problem for me (without doing XA) right? Because my data and job data are in different connections, right?

Best Answer

You can use a separate Transaction manager for tasks and the job repository. See here: http://forum.spring.io/forum/spring-projects/batch/39609-using-2-different-datasources-with-spring-batch

Thus, the need to designate two of them.

That being said, even though you can use two separate transaction managers, it doesn't mean that you should. If you don't go XA, then imagine what would happen if a business process ran successfully, but the job data wasn't saved. The next time the batch process ran, Spring Batch would think the job failed, and try to run it again.

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How to we share data between the different steps of a Job in Spring Batch

the job repository is used indirectly for passing data between steps (Jean-Philippe is right that the best way to do that is to put data into the StepExecutionContext and then use the verbosely named ExecutionContextPromotionListener to promote the step execution context keys to the JobExecutionContext.

It's helpful to note that there is a listener for promoting JobParameter keys to a StepExecutionContext as well (the even more verbosely named JobParameterExecutionContextCopyListener); you will find that you use these a lot if your job steps aren't completely independent of one another.

Otherwise you're left passing data between steps using even more elaborate schemes, like JMS queues or (heaven forbid) hard-coded file locations.

As to the size of data that is passed in the context, I would also suggest that you keep it small (but I haven't any specifics on the

Java – What’s the difference between @Component, @Repository & @Service annotations in Spring

From Spring Documentation:

The @Repository annotation is a marker for any class that fulfils the role or stereotype of a repository (also known as Data Access Object or DAO). Among the uses of this marker is the automatic translation of exceptions, as described in Exception Translation.

Spring provides further stereotype annotations: @Component, @Service, and @Controller. @Component is a generic stereotype for any Spring-managed component. @Repository, @Service, and @Controller are specializations of @Component for more specific use cases (in the persistence, service, and presentation layers, respectively). Therefore, you can annotate your component classes with @Component, but, by annotating them with @Repository, @Service, or @Controller instead, your classes are more properly suited for processing by tools or associating with aspects.

For example, these stereotype annotations make ideal targets for pointcuts. @Repository, @Service, and @Controller can also carry additional semantics in future releases of the Spring Framework. Thus, if you are choosing between using @Component or @Service for your service layer, @Service is clearly the better choice. Similarly, as stated earlier, @Repository is already supported as a marker for automatic exception translation in your persistence layer.

Annotation	Meaning
`@Component`	generic stereotype for any Spring-managed component
`@Repository`	stereotype for persistence layer
`@Service`	stereotype for service layer
`@Controller`	stereotype for presentation layer (spring-mvc)

Best Answer

Related Solutions

How to we share data between the different steps of a Job in Spring Batch

Java – What’s the difference between @Component, @Repository & @Service annotations in Spring

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