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Spring MVC Request Lifecycle

DispatcherServlet, handler mapping, and where validation and security plug in.

IntermediatePro11 min readBy Kishore BhosaleReviewed
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Why this matters

  • Tracing a request from Tomcat to your controller explains where filters, security, and validation run.
  • Misplaced logic in filters vs interceptors vs controllers is a common code-review failure mode.
  • Senior interviews ask you to draw the DispatcherServlet pipeline without looking at slides.

DispatcherServlet role

L1 · Fresher

One front controller maps URLs to @RequestMapping methods, invokes interceptors, and resolves return values to HTTP responses.

HandlerMapping chain

L2 · Intermediate

RequestMappingHandlerMapping picks the best matching controller method for path, method, and content type.

Argument resolvers

L3 · Advanced

@RequestBody, @PathVariable, and @RequestHeader are resolved before your method runs — failures become 400 via MethodArgumentNotValidException.

Async MVC return types

L4 · Expert

Callable, DeferredResult, and CompletableFuture release servlet threads; with virtual threads on Java 21, many teams skip async MVC for I/O-bound work.

HTTP request
DispatcherServlet
Controller method
ResponseEntity / ProblemDetail
One front controller delegates to mapped handlers, view resolvers, and exception handlers.

Hook

A client calls GET /api/books/42 with an expired JWT. BookStore must map the URL to BookController.getBook, run security filters, validate nothing on a GET, invoke the service, and return JSON — or a 401 before the controller runs. That path is the Spring MVC request lifecycle.

DispatcherServlet as front controller

Every HTTP request hits a single DispatcherServlet. It consults HandlerMapping beans to find a controller method, runs registered HandlerInterceptors, invokes the handler through HandlerAdapter, then uses HandlerExceptionResolver and ViewResolver (or message converters for REST) to build the response.

For BookStore, Boot auto-configures RequestMappingHandlerMapping and RequestMappingHandlerAdapter for annotated controllers.

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Still to come · 8 sections

  • Mapping to BookController
  • Argument resolution and validation
  • Interceptors and filters
  • Response rendering
  • BookStore in action
  • Runnable BookStore lab
  • Failure modes in production
  • Virtual threads on Java 21

Test yourself

Answer these before moving on — recall is what makes it stick.