Head First Servlets and JSP, 2nd Edition

How the Container handles a request

We’ll save some of the juicier bits for later in the book, but here’s a quick look:

1. 

   User clicks a link that has a URL to a servlet instead of a static page.

2. 

   The container “sees” that the request is for a servlet, so the container creates two objects:

   1) HttpServletResponse

   2) HttpServletRequest

3. 

   The container finds the correct servlet based on the URL in the request, creates or allocates a thread for that request, and passes the request and response objects to the servlet thread.

4. 

   The container calls the servlet’s service() method. Depending on the type of request, the service() method calls either the doGet() or doPost() method.

   For this example, we’ll assume the request was an HTTP GET.

5. 

   The container calls the servlet’s service() method. Depending on the type of request, the service() method calls either the doGet() or doPost() method. For this example, we’ll assume the request was an HTTP GET.

6. The thread completes, the container converts the response object into ...