Take a look at chapter 16 of "Spring Integration in Action": "Integrating Spring Batch and Spring Integration". It provides a very good overview of how to integrate Spring Batch and Spring Integration:
* Launching batch jobs through messages
* Providing feedback with informational messages (via StepListener, ChunkListener, JobExecutionListener)
* Externalize batch process execution (Call Spring Integration from inside batch jobs)
We talked a little bit about those options in our recent (2012) SpringOne talk: http://www.slideshare.net/hillert/introduction-to-spring-integration-and-spring-batch
There will also be an audio/video recording of that presentation available in the upcoming weeks/months.
As Spring Integration and Spring Batch are under the same umbrella of Spring projects, you will see an increasingly tighter integration between Spring Batch and Spring Integration. As for your specific situation, take a look at the features provided by Spring Batch. I believe one could make an argument that for simple use-cases with small batch files, you can do the job efficiently using Spring Integration only (Use the simple/more generic tool first). However, if you start dealing with massive files that don't easily fit into memory anymore, take a very long time to process, and you start feeling the pain, then you probably need to seriously consider Spring Batch. Other people may have a different view point but I hope this provides you with some useful guidance.
Disclaimer: I am a Spring Integration committer