<blc:form th:action="@{/search}" th:object="${searchForm}"  method="POST">
    <input type="search" class="search" name="q" th:value="${originalQuery}" />
        <span th:if="${#fields.hasErrors('searchText')}" th:errors="*{searchText}">dddd</span>
    <input type="submit" id="search_button" value="go" />
</blc:form>

@Controller
@RequestMapping("/search")
public class SearchController extends Mysearchcontroller {
    @RequestMapping("")
    public String search(HttpServletRequest request, HttpServletResponse response,
            @RequestParam(required = false) String q,@ModelAttribute("mysearchForm") Mysearchform mysearchForm,BindingResult errors,Model model) throws ServletException, IOException, ServiceException {
        return search3(model, request,response, q ,errors);
    }
}