mvc:annotation-driven vs defaults

[Some Developer]

Hello,

in the spring 3 core course handout i read the following:

"

<mvc:annotation-driven/>

Registers HandlerMapping and ~Adapter for @MVC.

- Means you loose the other default mappings and adapters!
"

What exactly am i loosing?

As I understand it, I can still use my annotations, and I even can use the stateless conversion service, REST and JSR-303 support.

Which defaults are no longer active when i use this tag?

[Marten Deinum]

The defaults of the dispatcher servlet are almost the same as the defaults of mvc:annotation-driven... There is a bit more setting up done for you... JSR-303 is detected (this isn't by the dispatcher servlet you need configuration for that), some HttpMessageConverters, depending on the included jars are pre-configured and instead of the DefaultAnnotationHandlerMapping (and accompaning HandlerAdapter) the RequestMappingHandlerMapping/-HandlerAdapter is registered, which is more powerful and flexible.

But if you have the course handout you probably want to ask your trainer

[Some Developer]

I even got certified,that's why its still bothering me
I agree that more powerfull things get activated. But what do i really loose?
I found a properties file next to the DispatcherServlet in the jar file (in the same package as the DispatcherServlet).
Are these the settings i'm loosing?

[Marten Deinum]

Well yes and no... I suggest take a look at the properties file and the WebMvcConfigurationSupport class (which is what registers the mvc:annotation-driven beans).

[Some Developer]

Hello,

this WebMvcConfigurationSupport class is a 3.1 spring class, not 3.0.
According to this link (watch the since attribute):

http://static.springsource.org/sprin...onSupport.html

I think the training docs are expressing 'loose' a bit too strong. From what i can see, you don't 'loose' anything. You get the same as the defaults but with some additional configuration.

These are the defaults i found in the DispatcherServlet.properties:

# Default implementation classes for DispatcherServlet's strategy interfaces.
# Used as fallback when no matching beans are found in the DispatcherServlet context.
# Not meant to be customized by application developers.

org.springframework.web.servlet.LocaleResolver=org.springframework.web.servlet.i18n.AcceptHeaderLocaleResolver

org.springframework.web.servlet.ThemeResolver=org.springframework.web.servlet.theme.FixedThemeResolver

org.springframework.web.servlet.HandlerMapping=org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping,\
	org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping

org.springframework.web.servlet.HandlerAdapter=org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter,\
	org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter,\
	org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter

org.springframework.web.servlet.HandlerExceptionResolver=org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerExceptionResolver,\
	org.springframework.web.servlet.mvc.annotation.ResponseStatusExceptionResolver,\
	org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver

org.springframework.web.servlet.RequestToViewNameTranslator=org.springframework.web.servlet.view.DefaultRequestToViewNameTranslator

org.springframework.web.servlet.ViewResolver=org.springframework.web.servlet.view.InternalResourceViewResolver

[Rossen Stoyanchev]

In Spring 3.1 both <mvc:annotation-driven> and the MVC Java config make sure you get all the extra DispatcherServlet.properties defaults so you don't lose anything really any more.