用了Acegi后如何从Login.jsp里传不过来parameter呢

用了Acegi后怎么从Login.jsp里传不过来parameter呢?


作为实验,在login.jsp里加一条<input type = "hidden" name = "testPara" value = "Spring"/>,想在Server端用
String teamType = httpServletRequest.getParameter("testPara");
        System.out.println("testPara: "+teamType);
看看能否得到这个testPara,可Console上的显示为:testPara: null.这是怎么回事?如何改进?