java后台请求前台input框的数据

jsp页面：

<div class="controls">
    <form:input path="carsn" name="carsn" htmlEscape="false" maxlength="100" class="input-xlarge required"/>
    <a href="${ctx}/common/passengercar/passengercar/findListByCarsn<%--?carsn=${passengercar.carsn}--%>">
        <input type="button" value="载入信息" class="btn btn-primary">
    </a>
</div>

controller：

@ResponseBody
@RequestMapping(value = "findListByCarsn")
public List<Passengercar> findListByCarsn(HttpServletRequest request, Model model) {

   //请求前台值
   String carsn = request.getParameter("carsn");

   List<Passengercar> pcList = passengercarService.findListByCarsn(carsn);
   model.addAttribute("pcList",pcList);
   return pcList;
   }