<form  method="post" th:action="${marca.id == null} ? @{/marcas/salvar} : @{/marcas/editar} " th:object="${marca}">
        <div class="form-row col-md-6">
            <!--<label for="id">Codigo</label>-->

            <label for="descricao">Descricao</label>
            <input type="text" class="form-control" id="descricao" autofocus="autofocus"  placeholder="Marca"
                   th:field="*{descricao}" th:classappend="${#fields.hasErrors('descricao')} ? 'is-invalid'"/>

            <div class="invalid-feedback" >
                <span th:errors="*{descricao}"></span>
            </div>
            <br/>
        </div>
        <input type="hidden" id="id" th:field="*{id}"/>
        <br/>
        <button type="submit" class="btn btn-primary btn-sm">Salvar</button>

    </form>

<div class="container" id="listagem">
    <div th:replace="fragments/alert"></div>
    <div class="table-responsive">
        <table class="table table-striped table-hover table-sm">
            <thead>
            <tr>
                <th>Cod.</th>
                <th>Descricao</th>
                <th>Acao</th>
            </tr>
            </thead>
            <tbody>
            <tr th:each="m : ${marcas}">
                <td th:text="${m.id}"></td>
                <td th:text="${m.descricao}"></td>
                <td><a class="btn btn-info btn-sm" th:href="@{/marcas/editar/{id} (id=${m.id})}" role="button">
                    <span class="oi oi-pencil" title="Editar" aria-hidden="true"></span>
                    </a>
                    <a class="btn btn-danger btn-sm" th:href="@{/marcas/excluir/{id} (id=${m.id})}" role="button" >
                        <span class="oi oi-circle-x" title="Excluir"></span>
                    </a>
                </td>
            </tr>
            </tbody>
        </table>
    </div>
</div>

@Controller
@RequestMapping("/marcas")
public class MarcaController {
    @Autowired
    private MarcaService service;
    @GetMapping("/cadastrar")
    public String cadastrar(ModelMap model){
        model.addAttribute("marca", new Marca());
        return "/marca/form";
    }
    @GetMapping("/listar")
    public String listar(ModelMap model){
        model.addAttribute("marcas", service.buscarTodos());
        return "/marca/list";
    }
    @PostMapping("/salvar")
    public String salvar(@Valid Marca marca, BindingResult result, RedirectAttributes attr) {
        if (result.hasErrors()){
            return "/marca/form";
        }
        service.salvar(marca);
        attr.addFlashAttribute("success", "Marca inserida com sucesso!");
        return "redirect:/marcas/listar";
    }
    @GetMapping("/editar/{id}")
    public String preEditar(@PathVariable("id") Long id, ModelMap model) {
        model.addAttribute("marca", service.buscarPorId(id));
        return "/marca/form";
    }
    @PostMapping("/editar")
    public String editar(@Valid Marca marca, BindingResult result, RedirectAttributes attr) {
        if (result.hasErrors()){
            return "/marca/form";
        }
        service.editar(marca);
        attr.addFlashAttribute("success", "Marca editada com sucesso!");
        return "redirect:/marcas/listar";
    }
    @GetMapping("/excluir/{id}")
    public String excluir(@PathVariable("id") Long id, RedirectAttributes attr) {
            service.excluir(id);
            attr.addFlashAttribute("success", "Marca excluida com sucesso");
            return "redirect:/marcas/listar";
    }
}