org.springframework.web.servlet.mvc

Class AbstractController

  • All Implemented Interfaces:
    Aware, ApplicationContextAware, ServletContextAware, Controller
    Direct Known Subclasses:
    AbstractUrlViewController, ParameterizableViewController, ServletForwardingController, ServletWrappingController


    public abstract class AbstractController
    extends WebContentGenerator
    implements Controller
    Convenient superclass for controller implementations, using the Template Method design pattern.

    Workflow (and that defined by interface):

    1. handleRequest() will be called by the DispatcherServlet
    2. Inspection of supported methods (ServletException if request method is not support)
    3. If session is required, try to get it (ServletException if not found)
    4. Set caching headers if needed according to the cacheSeconds property
    5. Call abstract method handleRequestInternal() (optionally synchronizing around the call on the HttpSession), which should be implemented by extending classes to provide actual functionality to return ModelAndView objects.

    Exposed configuration properties (and those defined by interface):

    name default description
    supportedMethods GET,POST comma-separated (CSV) list of methods supported by this controller, such as GET, POST and PUT
    requireSession false whether a session should be required for requests to be able to be handled by this controller. This ensures that derived controller can - without fear of null pointers - call request.getSession() to retrieve a session. If no session can be found while processing the request, a ServletException will be thrown
    cacheSeconds -1 indicates the amount of seconds to include in the cache header for the response following on this request. 0 (zero) will include headers for no caching at all, -1 (the default) will not generate any headers and any positive number will generate headers that state the amount indicated as seconds to cache the content
    synchronizeOnSession false whether the call to handleRequestInternal should be synchronized around the HttpSession, to serialize invocations from the same client. No effect if there is no HttpSession.
    Author:
    Rod Johnson, Juergen Hoeller, Rossen Stoyanchev
    See Also:
    WebContentInterceptor
    • Constructor Detail

      • AbstractController

        public AbstractController()
        Create a new AbstractController which supports HTTP methods GET, HEAD and POST by default.
      • AbstractController

        public AbstractController(boolean restrictDefaultSupportedMethods)
        Create a new AbstractController.
        Parameters:
        restrictDefaultSupportedMethods - true if this controller should support HTTP methods GET, HEAD and POST by default, or false if it should be unrestricted
        Since:
        4.3
    • Method Detail

      • setSynchronizeOnSession

        public final void setSynchronizeOnSession(boolean synchronizeOnSession)
        Set if controller execution should be synchronized on the session, to serialize parallel invocations from the same client.

        More specifically, the execution of the handleRequestInternal method will get synchronized if this flag is "true". The best available session mutex will be used for the synchronization; ideally, this will be a mutex exposed by HttpSessionMutexListener.

        The session mutex is guaranteed to be the same object during the entire lifetime of the session, available under the key defined by the SESSION_MUTEX_ATTRIBUTE constant. It serves as a safe reference to synchronize on for locking on the current session.

        In many cases, the HttpSession reference itself is a safe mutex as well, since it will always be the same object reference for the same active logical session. However, this is not guaranteed across different servlet containers; the only 100% safe way is a session mutex.

        See Also:
        handleRequestInternal(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse), HttpSessionMutexListener, WebUtils.getSessionMutex(javax.servlet.http.HttpSession)
      • isSynchronizeOnSession

        public final boolean isSynchronizeOnSession()
        Return whether controller execution should be synchronized on the session.
      • handleRequest

        @Nullable
        public ModelAndView handleRequest(HttpServletRequest request,
                                                    HttpServletResponse response)
                                             throws java.lang.Exception
        Description copied from interface: Controller
        Process the request and return a ModelAndView object which the DispatcherServlet will render. A null return value is not an error: it indicates that this object completed request processing itself and that there is therefore no ModelAndView to render.
        Specified by:
        handleRequest in interface Controller
        Parameters:
        request - current HTTP request
        response - current HTTP response
        Returns:
        a ModelAndView to render, or null if handled directly
        Throws:
        java.lang.Exception - in case of errors