Learning Vaadin 7 Nicolas Fränkel (web.xml yes or not)

Vaadin 6 / 7 / 8
1

I am reading the new book of Nicolas Fränkel ‘Learning Vaadin 7’ second Edition.
At the beginning it’s recommend declare :


<servlet-mapping>
<servlet-name My First Vaadin Application</servlet-name>
<url-pattern>/app/*</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name My First Vaadin Application</servlet-name>
<url-pattern>/VAADIN/*</url-pattern>
</servlet-mapping>

If i make a project with eclipse or with maven there is no more web.xml in the project.
I am confusing now.
Is it necessary to have a web.xml?

Thanks.

2

In Vaadin 7.1, i think it was, servlet configuration annotations for the UI class were introduced. These can replace the web.xml completely.
I personally still prefer using the web.xml (you can change an existing project just by removing the annotations and adding a web.xml in the src/main/webapp/WEB-INF/ folder containing all necessary mappings) because i ran into quite a lot of problems when using the annotations. (Sometimes the app just wasn’t reachable while the server was when i ran tomcat:run).

So it’s your choice. You can try using the annotations but if they don’t work for you or you don’t “like” them you can still change to the “old way”.

3

Servlet 3.0 annotations have always been usable on Servlet 3.0 compatible application servers as an alternative, but Vaadin 7.1 introduced a new annotation of its own that makes configuring such servlets considerably easier.

You can have both servlet 3.0 annotations and a web.xml, in which case your web.xml overrides the annotations. This enables e.g. the person responsible for deploying your application to reconfigure the application for production.

I personally prefer servlet 3.0 annotations but both methods are fine.