求助servlet获取初始化参数的问题 - 编程论坛

我用的是tomcat7.0，它的web.xml是自动配置的不用手工配置，我现在修改了其配置想设置一个参数在servlet中使用，但不知为什么读过来的参数为null
<servlet>
  <servlet-name>GetInitParameterServlet</servlet-name>
  <servlet-class>GetInitParameterServlet</servlet-class>
  <init-param>
  <param-name>repeat</param-name>
  <param-value>5</param-value>
  </init-param>
  </servlet>

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/html;charset=GBK");
        PrintWriter out=response.getWriter();
        out.println("<HTML>");
        out.println("<head><title>");
        out.println("</title></head>");
        out.println("<body>");
        int n=Integer.parseInt(this.getInitParameter("repeat"));
        for(int i=0;i<n;i++)
        {
            printContent(out);
        }
        out.println("</body>");
        out.println("</HTML>");
        out.flush();
        out.close();
    }
   public void printContent(PrintWriter out)
   {
       out.println("servlet");
   }