spring mvc接收put请求的数据失败。

controller代码节选：
@RequestMapping(value = "/update/{id}", method = RequestMethod.PUT)

public String update(HttpServletRequest request,
        HttpServletResponse response, ModelMap modelMap, Equipment equipment) {
    System.out.println(request.getParameter("name"));
    System.out.println(equipment.getIp());
    this.getEquipmentService().update(equipment);
    return "redirect:/equipment/list/json";
}

前端jQuery的ajax请求代码：

function putTest(){

    $.ajax('<%=request.getContextPath()%>/equipment/update/82f1c375-38d0-4c4b-bc15-e81e98fc4506',{type:'post',data:{_method:'put',id:'82f1c375-38d0-4c4b-bc15-e81e98fc4506',name:'设备1',ip:'127.0.0.1',port:'8887',updateTime:'2011-10-09 11:11:56'}});
}

web.xml添加了HiddenHttpMethodFilter：

<filter-name>HiddenHttpMethodFilter</filter-name>
<filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>

<filter-name>HiddenHttpMethodFilter</filter-name>
<servlet-name>DispatcherServlet</servlet-name>

按上面的配置，在前端点击按钮执行putTest方法后，后台的

System.out.println(request.getParameter("name"));
System.out.println(equipment.getIp());
正常输出数据。
但是把前端的的post方法改成put，后台的数据都接收不了了，输出为null。

$.ajax('<%=request.getContextPath()%>/equipment/update/82f1c375-38d0-4c4b-bc15-e81e98fc4506',{type:'put',data:{_method:'put',id:'82f1c375-38d0-4c4b-bc15-e81e98fc4506',name:'设备1',ip:'127.0.0.1',port:'8887',updateTime:'2011-10-09 11:11:56'}});
在firebug上也没查到有出错的信息。