public static Result removerItem(Long produto) {
    Form<FormularioCompra> formulario = Form.form(FormularioCompra.class).bindFromRequest();
    if (formulario.hasErrors()) {
      return badRequest(formularioCompra.render(formulario, new FormularioCompra()));
    }

    FormularioCompra item = formulario.get();

    FormularioCompra dto = criarOuObterDTOCompraSessao();
    dto.itens = removerItemDoDTO(produto, dto.itens);
    gravarDTOCompraSessao(dto);
    return ok(itens.render(dto.itens));
  }
  public static Result adicionarItem() {
    Form<FormularioCompra> formulario = Form.form(FormularioCompra.class).bindFromRequest();
    if (formulario.hasErrors()) {
      return badRequest(formularioCompra.render(formulario, new FormularioCompra()));
    }

    FormularioCompra item = formulario.get();
    FormularioCompra dto = criarOuObterDTOCompraSessao();
    dto.cnpj = item.cnpj;
    if (item.produto != null) {
      dto.itens.add(item);
      gravarDTOCompraSessao(dto);
    }
    formulario = Form.form(FormularioCompra.class);
    return ok(itens.render(dto.itens));
  }