DemoController.java

package com.example.myproject.demo.controller;

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;

@Controller
public class DemoController<ModelMapper> {

    private ModelMapper modelMapper;

    @GetMapping("/")
    public String index(Model model) {
        return "index";
    }
}