通过serialize()方法得到的值为username=xxx&password=xxx

$('#submit').click(function(){
        var data = $("form").serialize(); // 表单序列化
        $.ajax( {
            type : 'POST',url : '/admin/login',data : data,success : function(msg) {
                alert(msg);
            }
        });
    });

后台映射方法通过HttpServletRequest 获取值

@RequestMapping(value = "/login",method = RequestMethod.POST)
    @ResponseBody
    public String login(HttpServletRequest request) {
        String username = request.getParameter("username");
        String password = request.getParameter("password");
    }