Special Bean Types

See equivalent in the Reactive stack

The DispatcherServlet delegates to special beans to process requests and render the appropriate responses. By “special beans” we mean Spring-managed Object instances that implement framework contracts. Those usually come with built-in contracts, but you can customize their properties and extend or replace them.

The following table lists the special beans detected by the DispatcherServlet:

Bean type Explanation

Bean type	Explanation
`HandlerMapping`	Map a request to a handler along with a list of interceptors for pre- and post-processing. The mapping is based on some criteria, the details of which vary by `HandlerMapping` implementation. The two main `HandlerMapping` implementations are `RequestMappingHandlerMapping` (which supports `@RequestMapping` annotated methods) and `SimpleUrlHandlerMapping` (which maintains explicit registrations of URI path patterns to handlers).
`HandlerAdapter`	Help the `DispatcherServlet` to invoke a handler mapped to a request, regardless of how the handler is actually invoked. For example, invoking an annotated controller requires resolving annotations. The main purpose of a `HandlerAdapter` is to shield the `DispatcherServlet` from such details.
`HandlerExceptionResolver`	Strategy to resolve exceptions, possibly mapping them to handlers, to HTML error views, or other targets. See Exceptions.
`ViewResolver`	Resolve logical `String`-based view names returned from a handler to an actual `View` with which to render to the response. See View Resolution and View Technologies.
`LocaleResolver`, LocaleContextResolver	Resolve the `Locale` a client is using and possibly their time zone, in order to be able to offer internationalized views. See Locale.
`ThemeResolver`	Resolve themes your web application can use — for example, to offer personalized layouts. See Themes.
`MultipartResolver`	Abstraction for parsing a multi-part request (for example, browser form file upload) with the help of some multipart parsing library. See Multipart Resolver.
`FlashMapManager`	Store and retrieve the “input” and the “output” `FlashMap` that can be used to pass attributes from one request to another, usually across a redirect. See Flash Attributes.

HandlerMapping

Map a request to a handler along with a list of interceptors for pre- and post-processing. The mapping is based on some criteria, the details of which vary by HandlerMapping implementation.

The two main HandlerMapping implementations are RequestMappingHandlerMapping (which supports @RequestMapping annotated methods) and SimpleUrlHandlerMapping (which maintains explicit registrations of URI path patterns to handlers).

HandlerAdapter

Help the DispatcherServlet to invoke a handler mapped to a request, regardless of how the handler is actually invoked. For example, invoking an annotated controller requires resolving annotations. The main purpose of a HandlerAdapter is to shield the DispatcherServlet from such details.

HandlerExceptionResolver

Strategy to resolve exceptions, possibly mapping them to handlers, to HTML error views, or other targets. See Exceptions.

ViewResolver

Resolve logical String-based view names returned from a handler to an actual View with which to render to the response. See View Resolution and View Technologies.

LocaleResolver, LocaleContextResolver

Resolve the Locale a client is using and possibly their time zone, in order to be able to offer internationalized views. See Locale.

ThemeResolver

Resolve themes your web application can use — for example, to offer personalized layouts. See Themes.

MultipartResolver

Abstraction for parsing a multi-part request (for example, browser form file upload) with the help of some multipart parsing library. See Multipart Resolver.

FlashMapManager

Store and retrieve the “input” and the “output” FlashMap that can be used to pass attributes from one request to another, usually across a redirect. See Flash Attributes.