Package org.springframework.web.context.request

Interface WebRequestInterceptor

  • All Known Subinterfaces:
    AsyncWebRequestInterceptor
    All Known Implementing Classes:
    OpenEntityManagerInViewInterceptor, OpenSessionInViewInterceptor
    public interface WebRequestInterceptor
    Interface for general web request interception. Allows for being applied to Servlet request by building on the WebRequest abstraction.

    This interface assumes MVC-style request processing: A handler gets executed, exposes a set of model objects, then a view gets rendered based on that model. Alternatively, a handler may also process the request completely, with no view to be rendered.

    In an async processing scenario, the handler may be executed in a separate thread while the main thread exits without rendering or invoking the postHandle and afterCompletion callbacks. When concurrent handler execution completes, the request is dispatched back in order to proceed with rendering the model and all methods of this contract are invoked again. For further options and comments see org.springframework.web.context.request.async.AsyncWebRequestInterceptor

    This interface is deliberately minimalistic to keep the dependencies of generic request interceptors as minimal as feasible.

    Since:
    2.0
    Author:
    Juergen Hoeller
    See Also:
    ServletWebRequest, DispatcherServlet, AbstractHandlerMapping.setInterceptors(java.lang.Object...), HandlerInterceptor

    • Method Detail

      • preHandle

        void preHandle​(WebRequest request)
        throws Exception
        Intercept the execution of a request handler before its invocation.

        Allows for preparing context resources (such as a Hibernate Session) and expose them as request attributes or as thread-local objects.

        Parameters:
        request - the current web request
        Throws:
        Exception - in case of errors

      • postHandle

        void postHandle​(WebRequest request,
                @Nullable
                ModelMap model)
         throws Exception
        Intercept the execution of a request handler after its successful invocation, right before view rendering (if any).

        Allows for modifying context resources after successful handler execution (for example, flushing a Hibernate Session).

        Parameters:
        request - the current web request
        model - the map of model objects that will be exposed to the view (may be null). Can be used to analyze the exposed model and/or to add further model attributes, if desired.
        Throws:
        Exception - in case of errors

      • afterCompletion

        void afterCompletion​(WebRequest request,
                     @Nullable
                     Exception ex)
              throws Exception
        Callback after completion of request processing, that is, after rendering the view. Will be called on any outcome of handler execution, thus allows for proper resource cleanup.

        Note: Will only be called if this interceptor's preHandle method has successfully completed!

        Parameters:
        request - the current web request
        ex - exception thrown on handler execution, if any
        Throws:
        Exception - in case of errors