RequestMapping

RequestMapping is a fundamental annotation in the Spring Framework, primarily used in Spring MVC and Spring WebFlux applications. It serves to map web requests to specific handler methods within a controller class. When a request arrives at the application, Spring examines the request's URL, HTTP method (GET, POST, PUT, DELETE, etc.), and other attributes to determine which handler method should process it.

The annotation can be applied at both the class level and the method level. When applied at the class level, it defines a base URL path that all methods within that controller will share. Method-level annotations then specify more granular mappings, allowing for different methods to handle distinct endpoints or variations of the base path.

Key attributes of the RequestMapping annotation include its ability to specify the path, the HTTP method(s) it handles, and parameters. For instance, one can define a mapping like @RequestMapping(value = "/users", method = RequestMethod.GET) to indicate that a particular method should handle GET requests to the "/users" endpoint. This annotation is crucial for building RESTful APIs and web applications, as it provides a clear and declarative way to connect incoming requests to the appropriate application logic. Its flexibility allows developers to manage routing and request handling efficiently.