Expert Spring MVC and Web Flow

Types of ViewResolver

ViewResolveris a strategy interface within the framework. In order to get a better handle on how

view resolution is applied through this interface, we’ll introduce some of the abstract and con-

crete implementations. Figure 7-5 details the relationships between various ViewResolverclasses.

Figure 7-5.ViewResolver hierarchy

That’s a lot of ViewResolvers, so what do they all do? Let’s briefly examine some of the

more important ones.

• BeanNameViewResolveris a simple implementation of the interface that is useful
  in smaller applications. It attempts to resolve views as beans defined in the
  ApplicationContext, so the name of the view is the idof a bean. This resolver needs
  no additional configuration, but it has the disadvantage of requiring view beans to be
  defined in the ApplicationContextfile.


• AbstractCachingViewResolveris the superclass to all resolvers that wish to cache their
  view objects. Creating a Viewcan be an expensive operation, so this is a useful piece of
  common functionality.


• XmlViewResolvercreates views based on an XML definition file. This file (/WEB-INF/
  views.xmlby default) uses the Spring Beans DTD, which has the advantage of making
  view definitions both familiar and able to use the full power of Spring’s bean factories.

ViewResolver

+ resolveViewname(viewName : string, locale : Locale) : View

AbstractCachingViewResolver BeanNameViewResolver

ResourceBundleViewResolver XmlViewResolver UrlBasedViewResolver

InternalResourceViewResolver AbstractTemplateViewResolver

VelocityViewResolver FreeMarkerViewResolver

210 CHAPTER 7 ■THE VIEW LAYER