Java EE 8 Cookbook

How it works...

Let's split up the code shown earlier, so that we can better understand what's happening.

In the web.xml file, we are creating a security constraint:

    <security-constraint>       ...    </security-constraint>

We're defining a resource inside it:

        <web-resource-collection>            <web-resource-name>CH05-Authentication</web-resource-name>            <url-pattern>/authServlet</url-pattern>        </web-resource-collection>

And we're defining an authorization policy. In this case, it's a role:

        <auth-constraint>            <role-name>role1</role-name>        </auth-constraint>

Now we have UserAuthenticationServlet. We should pay attention to this annotation:

@DeclareRoles({"role1", "role2", "role3"})

It defines which roles are part of the context of this particular servlet.

Another ...