Multithreading in JDBC connectivity

Question

i am trying to upload a file into the server and storing the information of the file into an Access database, is there any need to handle the threads while database connectivity for multiple user. If yes how to do it?

Answer 1

Your webserver is inheritly multithreaded, that saves you from implementing you own threads to handle the uploads. Do however make sure that multiple requests dont use same resources (dont write all uploaded file in the same tmp file,....)

To avoid problems saving the data to your db, use a Connection Pool.

So yes you need threads but if your design is good then all the threading will be handled by your frameworks

Answer 2

Exactly. Each HTTP request is already a thread at its own. Keep in mind that the web container will create only one servlet instance during application's lifetime and that the servlet code is been shared among all requests. This implies that any class-level variables or static variables are going to be shared among all requests. If you have such one variable, it is not threadsafe. You need to declare request-specific variables threadlocal at method-level.

As to JDBC: just write solid code and everything should go well. Using a connection pool is only useful to improve connecting performance (which is really worth the effort, believe me, connecting the DB is a fairly expensive task which may account up to at least 200ms or even more, while reusing a connection from the pool costs almost nothing). It only doesn't change anything to the threadsafety of the code you write, it's still in your control/hands. To get a clear picture of how to do the basic JDBC coding the right way, you may find this article useful.