ssm+ajax页面跳转问题

用ssm和ajax做了用户登录注册功能，结果发现登录成功之后页面返回了一个字符串

controller层

@RequestMapping("dologin")
    @ResponseBody
    public boolean dologin(@RequestParam("username") String username,
                           @RequestParam("password")String password, User user, Model model, HttpSession session
    , HttpServletRequest request, HttpServletResponse response){

        user = userService.login(user.getUsername(), user.getPassword());

        Boolean flag ;
        response.setContentType("text/html;charset=UTF-8");
        response.setCharacterEncoding("UTF-8");
//        user.setUsername(username);
//        user.setPassword(password);
        System.out.println("dologin");
        if(userService.login(username,password) != null)
        {
            model.addAttribute("username", username);
            session.setAttribute("user",user);
            flag =  true;
//            model.setViewName("Dashboard/index");
        } else {
            System.out.println("账号或密码错误");
            flag = false;
//            mv.setViewName("tutorial/tologin");
        }
        return flag;
//        System.out.println(model);
//        return mv;
    }

登录按钮

<form class="login-form" action="${pageContext.request.contextPath}/dologin" method="post">
            <input type="text" name="username" placeholder="username"/>
            <input type="password" name="password" placeholder="password"/>
            <button type="submit" value="login" id="loginBtn" >Login</button>
            <p class="message">无账号？ <a href="#">创建账号</a></p>
        </form>

ajax

$(function() {
        $("#loginBtn").click(function() {
            var username = $("#username").val();
            var password = $("#password").val();
            $.ajax({
                type:"POST",
                url:"dologin",
                data:{"username" : username,
                        "password" : password},
                dataType:"json",
                success:function(flag){
                    console.log("进入ajax")
                    if(flag){
                        window.location.href="Dashboard/index.jsp";
                    }else{
                        alert("登录失败");;
                    }
                }
            });
        });
    });

不是很懂，求大神支招。

想用异步更新实现登陆注册功能。

你的代码返回的就是true,要想跳转应该返回地址