Spring Batch: starting a job from within a Spring MVC contorller WITH A NEW THREAD

Question

I have a Spring-Batch job that I launch from a Spring MVC controller. The controller gets an uploaded file from the user and the job is supposed to process the file:

Answer 1

If you don't need to show the processing errors to your client, you can start the spring batch job in a seperate thread.

Answer 2

The jobLauncher.run() method can be called in a new Thread like so:

@RequestMapping(value = "/upload")
public ModelAndView uploadInventory(UploadFile uploadFile, BindingResult bindingResult) {
  [...]

  final SomeObject jobLauncher = [...]
  Thread thread = new Thread(){
    @Override
    public void run(){
      jobLauncher.run([...]);
    }
  };
  thread.start();

  return mav;
}

The thread.start() line will spawn a new thread, and then continue to execute the code below it.

Note that, if jobLauncher is a local variable, it must be declared final in order for it to be used inside of the anonymous Thread class.

Answer 3

The official documentation describes your exact problem and a solution in 4.5.2. Running Jobs from within a Web Container:

[...] The controller launches a Job using a JobLauncher that has been configured to launch asynchronously, which immediately returns a JobExecution. The Job will likely still be running, however, this nonblocking behaviour allows the controller to return immediately, which is required when handling an HttpRequest.

Spring Batch http://static.springsource.org/spring-batch/reference/html-single/images/launch-from-request.png

So you were pretty close in trying to use TaskExecutor, however it needs to be passed to the JobLauncher instead:

<bean id="jobLauncher"
      class="org.springframework.batch.core.launch.support.SimpleJobLauncher">
    <property name="jobRepository" ref="jobRepository" />
    <property name="taskExecutor" ref="taskExecutor"/>
</bean>

^{Disclaimer: I have never used Spring Batch...}