Why is text being returned instead of a pattern?

Question

Spring

I want to return the template through the controller, but for some reason the text is returned. Everything seems to be like in the guide from the Spring website.
Tell me, please, what could be the problem?

package com.example.test.controller;

import com.example.test.entity.User;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class RegistrationController {
    @GetMapping("/")
    public String greeting() {
        return "index";
    }

    @PostMapping("/registrtion")
    public User registration(@RequestBody User user) {
        return user;
    }
}

Answer 1

Good afternoon!
Not right:

@RestController
public class RegistrationController {

Should be:

@Controller
public class RegistrationController {

Read about:
https://www.baeldung.com/spring-controller-vs-rest...
Then another error:
your POST request runs to registration
A in the controller:
@PostMapping("/registrtion")