哪些servlet不属于Web应用程序

Question

Servlet specification SRV.3.2 says

Servlets in a container that were not deployed as part of aWeb application are implicitly part of a “default” Web application and have a default ServletContext.

so how can we create serlvets those are not part of web application and what is the use of them?

Answer 1

Take a look at section SRV.9.1:

SRV.9.1 Web Applications Within Web Servers

A web application is rooted at a specific path within a web server. For example, a catalog application could be located at http://www.example.com/catalog . All requests that start with this prefix will be routed to the ServletContext which represents the catalog application.

Servlets that are not part of a web application are therefore servlets that are not rooted at a specific path. In other words, they're rooted at the / path, and their use is to serve content from there.

Note that this is pretty awkward to begin with (as the verbose text already shows), so most web application servers let you designate an application to run at the 'root' context path in some other way.