spring-mvc 前端post表單數據到后臺，后臺沒有接收到，并且用HttpServletRequest獲取參數列表為空，下面為代碼：web.xml:<servlet>        <servlet-name>embers</servlet-name>        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>        <init-param>            <param-name>contextConfigLocation</param-name>            <param-value>classpath:conf/embers-mvc.xml</param-value>        </init-param>        <load-on-startup>1</load-on-startup>        <async-supported>true</async-supported>    </servlet>    <servlet-mapping>        <servlet-name>embers</servlet-name>        <url-pattern>/rest/*</url-pattern>    </servlet-mapping>mvc配置文件：<context:component-scan base-package="embers.blog.controller" />controller：@Controllerpublic class BugTestController {            @RequestMapping(value="/demo",method=RequestMethod.POST)    public String demo(HttpServletRequest request,HttpServletResponse response) throws IOException{        System.out.println(request.getParameterMap());        System.out.println(request.getParameter("username"));        System.out.println(request.getParameter("password"));        System.out.println(request.getContentType());        System.out.println("//");        response.setContentType("text/html");        response.getWriter().println("keke");        response.getWriter().flush();        response.getWriter().close();        return null;    }}我已經調試過無數次了，如果設定為GET方法，然后把參數放在URL上是完全沒有問題的，用json提交，配置json轉換也是沒有問題的，就是默認的POST表單數據有問題，下面是調試工具生成的表單完整報文：POST /BugTest/rest/demo HTTP/1.1Host: 127.0.0.1:8080Content-Type: application/x-www-form-urlencodedCache-Control: no-cacheusername=111wqfewrf&password=321&=一直都是好好的，這么簡單的demo，現在突然不行了，好久沒寫springmvc了，我漏了什么嗎？