Spring MVC and REST

Cert Focus

You should understand the request lifecycle and how controllers map requests, read input, return responses, validate data, and handle errors.

Must Know

• DispatcherServlet is the front controller.
• @Controller returns views unless response body behavior is used.
• @RestController combines @Controller and @ResponseBody.
• @RequestMapping and shortcut annotations map requests.
• @PathVariable, @RequestParam, and @RequestBody bind request data.
• @Valid triggers validation.
• @ExceptionHandler and @ControllerAdvice centralize error handling.

Direct Book Links

• Spring MVC Mental Model
• Request Mapping Deep Dive
• Request and Response Bodies
• Exception Handling in Spring MVC
• Spring MVC Validation
• Week 4 Review

Exam Trap

@RequestBody reads the HTTP body. @ResponseBody writes the return value to the HTTP response body.

Self-Check

• Can I explain DispatcherServlet?
• Can I choose between @RequestParam, @PathVariable, and @RequestBody?
• Can I explain how validation is triggered?
• Can I explain how global exception handling works?

Model Answers

DispatcherServlet is the front controller. It receives HTTP requests and coordinates handler mapping, binding, controller execution, and response rendering.

Use @RequestParam for query parameters or form values, @PathVariable for values inside the URL path, and @RequestBody for JSON or other request body content.

Validation is commonly triggered by adding @Valid or @Validated to a controller method parameter and having validation constraints on the target object.

Global exception handling is commonly implemented with @ControllerAdvice plus @ExceptionHandler, so multiple controllers can share consistent error responses.

Memory Sentence

Spring MVC routes the request, binds input, calls the controller, and writes the response.