What is the role and function of the Router component in Java applications?

In Java applications, the Router component is responsible for request routing — that is, it determines which code or controller should handle an incoming HTTP request based on the URL and other parameters. It is a key element in web frameworks (for example, Spring MVC), which links URLs to handler methods.

Main functions of the Router:

• Parsing URLs and matching them with routes.
• Passing control to the appropriate handler.
• Supporting route parameters (e.g., /user/{id}).
• Ability to configure filters and middleware.

Example in Spring Boot:

@RestController
public class UserController {
    @GetMapping("/users/{id}")
    public User getUser(@PathVariable String id) {
        // logic to get user by id
    }
}

Here, the Router automatically directs requests like /users/123 to the getUser method with the parameter id = 123.