In my Spring Boot application based on version 1.3.0.BUILD-SNAPSHOT, I have the static resources (images, css, js) in the static
folder un
Well in the code you shared, if you had your static files i.e. CSS/JS etc in a folder called static then all your static resources will be added to the page whereas if you left out
web.ignoring()
.antMatchers("/static/**");
none of your static resources will be loaded.
Spring Security is extremely powerful, Spring has great documentation so you should just go read about it fully appreciate/understand it.
Here is a link