Java Web应用程序中的并发

Question

I have created a Java Web Application that asks the user to upload an ARF File, converts it to MP4 and saves it on the server and the user is then sent an email with the link of the new MP4 file. The conversion takes place by calling a VB Script from the command line. This script converts all the ARF files that are located in a desired directory to MP4 format.

The application has been working well but I have noticed one thing. It does not work when one person (using one computer) runs the application and say the file is in the process of being converted (ie the user is waiting for the email). At this stage if another user (using another computer) tries to run the application at the same time, the conversion process gets disrupted and it stops the previous conversion.

I tried testing the VB Script by running it, waiting for a video to be converting and then running it again. I noticed the same thing.

Was wondering if there is a way to make my application concurrent so that it can run independently ie more than one person can run it at the same time.

Thank you

Answer 1

The limitation here is the limitations of the VB script. Can you (for example) generate a different filename for each so that it works in parallel?

If not then you will have to queue up the requests and then have some code that processes the next request from the queue one at a time.

Answer 2

It sounds like the code that invokes the VB script is the bottleneck. I take it that the file conversion process would take some amount of time so that what you want is have the processing started in a background thread and terminate the java session. The first thing that came to my mind is Quartz job framework. You can trigger a Quartz job that does the processing and emailing and each Quartz job is running on its own thread. http://quartz-scheduler.org/documentation