Java spring 3中列表的双向绑定

所以问题是下一个。我在Spring3.2上有一个带有jsp页面的控制器。在get方法上，我发送到ui模型，如下所示：

public UserModel {
   
   List<Country> counties;
 
   String countryCode;
   
  // some getters and setters
}

 <form:select id="countryCode" name="${status.expression}" path="userModel.countryCode" multiple="false">
       <form:option value="0"><fmt:message key="common.admin.userInfo.countrySelectLabel"/></form:option>
       <form:options items="${userModel.countries}" itemValue="isoCode" itemLabel="countryName"/>
 </form:select>

 public String saveNewUser(@Valid @ModelAttribute("userModel") UserModel userModel, BindingResult result, HttpServletRequest httpServletRequest, Model model) {

        String path = (String) httpServletRequest.getAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE);
        if (result.hasErrors()) {
            return path.substring(0, path.length() - 4);
        }
}