Question

I have seen an example of Singleton class object where it has a map containing user-id and password retrieved from database. This will help not to hit DB everytime during user login.

Now i am thinking, can’t this be done through ServletContext attribute.

Basically on both the cases we will have application wide object.

So, Can we use ServletContext attribute in this case.

Answer 1

If you need to access the Map from anywhere in your application then yes it is actually the best place to place it.

You can register a Servlet Context Listener and on contextInitialized you can get a singleton and store it as an attribute of ServletContext

Then access it using by anywhere in your web application by getting the corresponding attribute

getServletContext().getAttribute("UsersMap");