What is Spring Web?

Spring Web is a part of the Spring Framework that provides functionality for building web applications. It includes the Spring MVC and Spring WebFlux modules, which support the Servlet API and reactive stack, respectively.

Key components of Spring Web:

• Spring MVC: A module for creating web applications based on the Model-View-Controller pattern. It provides:
  • DispatcherServlet - the central controller routing incoming requests.
  • @Controller and @RestController annotations for defining controllers.
  • Request mapping mechanisms (annotations like @RequestMapping, @GetMapping, etc.).
  • Support for View Resolvers for rendering views.
  • Data validation mechanisms.
  • Support for RESTful web services.
• Spring WebFlux: A module for creating reactive web applications using non-blocking I/O. It supports:
  • Reactive data streams (Project Reactor).
  • Functional endpoints (instead of annotated controllers).
  • Various reactive web servers (Netty, Undertow, Jetty).

Comparison of Spring MVC and Spring WebFlux:

Characteristic	Spring MVC	Spring WebFlux
I/O Stack	Blocking (Servlet API)	Non-blocking (Reactive)
Architecture	Thread-per-request	Event loop
Throughput	Lower under high load	Higher under high load
Complexity	Simpler	More complex (requires understanding reactive programming)
Typical use	Traditional web applications	High-load, reactive services

Thus, Spring Web provides powerful tools for creating both traditional and reactive web applications in Java, offering flexibility and high performance.