Package org.springframework.web.servlet

Interface HandlerMapping

All Known Subinterfaces:
MatchableHandlerMapping
All Known Implementing Classes:
AbstractDetectingUrlHandlerMapping, AbstractHandlerMapping, AbstractHandlerMethodMapping, AbstractUrlHandlerMapping, BeanNameUrlHandlerMapping, RequestMappingHandlerMapping, RequestMappingInfoHandlerMapping, RouterFunctionMapping, SimpleUrlHandlerMapping, WebSocketHandlerMapping
public interface HandlerMapping
Interface to be implemented by objects that define a mapping between requests and handler objects.

This class can be implemented by application developers, although this is not necessary, as BeanNameUrlHandlerMapping and RequestMappingHandlerMapping are included in the framework. The former is the default if no HandlerMapping bean is registered in the application context.

HandlerMapping implementations can support mapped interceptors but do not have to. A handler will always be wrapped in a HandlerExecutionChain instance, optionally accompanied by some HandlerInterceptor instances. The DispatcherServlet will first call each HandlerInterceptor's preHandle method in the given order, finally invoking the handler itself if all preHandle methods have returned true.

The ability to parameterize this mapping is a powerful and unusual capability of this MVC framework. For example, it is possible to write a custom mapping based on session state, cookie state or many other variables. No other MVC framework seems to be equally flexible.

Note: Implementations can implement the Ordered interface to be able to specify a sorting order and thus a priority for getting applied by DispatcherServlet. Non-Ordered instances get treated as the lowest priority.

Author:
Rod Johnson, Juergen Hoeller
See Also:

  • Field Details

    • BEST_MATCHING_HANDLER_ATTRIBUTE

      static final String BEST_MATCHING_HANDLER_ATTRIBUTE
      Name of the HttpServletRequest attribute that contains the mapped handler for the best matching pattern.
      Since:
      4.3.21

    • LOOKUP_PATH

      @Deprecated static final String LOOKUP_PATH
      Deprecated.
      as of 5.3 in favor of UrlPathHelper.PATH_ATTRIBUTE and ServletRequestPathUtils.PATH_ATTRIBUTE. To access the cached path used for request mapping, use ServletRequestPathUtils.getCachedPathValue(ServletRequest).
      Name of the HttpServletRequest attribute that contains the path used to look up the matching handler, which depending on the configured UrlPathHelper could be the full path or without the context path, decoded or not, etc.
      Since:
      5.2

    • PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE

      static final String PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE
      Name of the HttpServletRequest attribute that contains the path within the handler mapping, in case of a pattern match, or the full relevant URI (typically within the DispatcherServlet's mapping) else.

      Note: This attribute is not required to be supported by all HandlerMapping implementations. URL-based HandlerMappings will typically support it, but handlers should not necessarily expect this request attribute to be present in all scenarios.

    • BEST_MATCHING_PATTERN_ATTRIBUTE

      static final String BEST_MATCHING_PATTERN_ATTRIBUTE
      Name of the HttpServletRequest attribute that contains the best matching pattern within the handler mapping.

      Note: This attribute is not required to be supported by all HandlerMapping implementations. URL-based HandlerMappings will typically support it, but handlers should not necessarily expect this request attribute to be present in all scenarios.

    • INTROSPECT_TYPE_LEVEL_MAPPING

      static final String INTROSPECT_TYPE_LEVEL_MAPPING
      Name of the boolean HttpServletRequest attribute that indicates whether type-level mappings should be inspected.

      Note: This attribute is not required to be supported by all HandlerMapping implementations.

    • URI_TEMPLATE_VARIABLES_ATTRIBUTE

      static final String URI_TEMPLATE_VARIABLES_ATTRIBUTE
      Name of the HttpServletRequest attribute that contains the URI templates map, mapping variable names to values.

      Note: This attribute is not required to be supported by all HandlerMapping implementations. URL-based HandlerMappings will typically support it, but handlers should not necessarily expect this request attribute to be present in all scenarios.

    • MATRIX_VARIABLES_ATTRIBUTE

      static final String MATRIX_VARIABLES_ATTRIBUTE
      Name of the HttpServletRequest attribute that contains a map with URI variable names and a corresponding MultiValueMap of URI matrix variables for each.

      Note: This attribute is not required to be supported by all HandlerMapping implementations and may also not be present depending on whether the HandlerMapping is configured to keep matrix variable content

    • PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE

      static final String PRODUCIBLE_MEDIA_TYPES_ATTRIBUTE
      Name of the HttpServletRequest attribute that contains the set of producible MediaTypes applicable to the mapped handler.

      Note: This attribute is not required to be supported by all HandlerMapping implementations. Handlers should not necessarily expect this request attribute to be present in all scenarios.

  • Method Details

    • usesPathPatterns

      default boolean usesPathPatterns()
      Whether this HandlerMapping instance has been enabled to use parsed PathPatterns in which case the DispatcherServlet automatically parses the RequestPath to make it available for access in HandlerMappings, HandlerInterceptors, and other components.
      Since:
      5.3

    • getHandler

      @Nullable HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception
      Return a handler and any interceptors for this request. The choice may be made on request URL, session state, or any factor the implementing class chooses.

      The returned HandlerExecutionChain contains a handler Object, rather than even a tag interface, so that handlers are not constrained in any way. For example, a HandlerAdapter could be written to allow another framework's handler objects to be used.

      Returns null if no match was found. This is not an error. The DispatcherServlet will query all registered HandlerMapping beans to find a match, and only decide there is an error if none can find a handler.

      Parameters:
      request - current HTTP request
      Returns:
      a HandlerExecutionChain instance containing handler object and any interceptors, or null if no mapping found
      Throws:
      Exception - if there is an internal error