Running Jobs from within a Web Container

Historically, offline processing (such as batch jobs) has been launched from the command-line, as described earlier. However, there are many cases where launching from an HttpRequest is a better option. Many such use cases include reporting, ad-hoc job running, and web application support. Because a batch job (by definition) is long running, the most important concern is to launch the job asynchronously:

 

Figure 1. Asynchronous Job Launcher Sequence From Web Container

 

 

The controller in this case is a Spring MVC controller. See the Spring Framework Reference Guide for more about Spring MVC. The controller launches a Job by using a JobLauncher that has been configured to launch asynchronously, which immediately returns a JobExecution. The Job is likely still running. However, this nonblocking behavior lets the controller return immediately, which is required when handling an HttpRequest. The following listing shows an example:

@Controller
public class JobLauncherController {

    @Autowired
    JobLauncher jobLauncher;

    @Autowired
    Job job;

    @RequestMapping("/jobLauncher.html")
    public void handle() throws Exception{
        jobLauncher.run(job, new JobParameters());
    }
}

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