Using servlets for request and response management

Servlets are the core place to deal with requests and responses using Java EE. If you are still not familiar with it, know that even a JSP is nothing more than a way to build a servlet once the page is called.

This recipe will show you three features you can use when using servlets:

• Load on startup
• Parameterized servlets
• Asynchronous servlets

Getting ready

Start by adding the dependency to your project:

        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-api</artifactId>
            <version>8.0</version>
            <scope>provided</scope>
        </dependency>

How to do it...

The load on startup servlet

Let's start with our servlet that will load on the server's start up:

@WebServlet(name = "LoadOnStartupServlet", urlPatterns = {"/LoadOnStartupServlet"}, 
loadOnStartup = 1)
public class LoadOnStartupServlet extends HttpServlet {

    @Override
    public...