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Inter-Servlet Communication

Ryan Nordman

Joined: Apr 30, 2007
Posts: 1

I'm writing two servlets, and I would like one to call the other.
Each one will reside on seperate machines.

Let's call them servlet1 and servlet2. servlet1 needs to pass a file
to servlet2. So I'd like to call up servlet2's doPost method and pass
in the file that way. Then when servlet2 is finished doing its work,
it needs to pass back a different file that it has created. So I'm
thinking I would just dump the return file into the response and that
would come back to servlet1. Is that the most sensible way to do it?
If not, please enlighten me! If so, can anybody point me in the right
direction with code examples?

I've gotten as far as using a URL connection object to open the connection between servlets. Now I just need to be able to grab the response from servlet2 and copy it to the response servlet1 is going to send to the client.

Thanks in advance,
Ulf Dittmer

Joined: Mar 22, 2005
Posts: 42965
Welcome to JavaRanch.

For transferring files, I'd use Jakarta Commons HttpClient on the client side, and Jakarta Commons FileUpload on the server side. Some information about how that can work can be found at the FileUpload FAQ page.

Instead of using this approach I'd rather use an FTP server that's accessible by both servlets, though, and just use a quick HTTP call to let the receiving side know that something new has been uploaded. That decouples things a bit, allowing both sides to work at different speeds. (Unless your application needs the synchronicity.)
I agree. Here's the link:
subject: Inter-Servlet Communication
jQuery in Action, 3rd edition