为啥我的json串直接显示在了前端页面上啊
而且断点调试没有给data赋值就输出了，data里面还有值。

jsp代码

function dologin() {
        var floginacct = $("#floginacct");
        var fuserpswd = $("#fuserpswd");
        var  ftype = $("#ftype");
        var flag = $("#remberme")[0].checked;
        //对于表单而言，不能用null进行判断，如果文本框什么都不输入，获取的值为“”
        if($.trim(floginacct.val())=="") {
            /*alert("用户账户不能为空，请重新输入！");*/
            layer.msg("用户账号不能为空,请重新输入!", {time:1000, icon:5, shift:6}, function(){
                floginacct.val("");
                floginacct.focus();//设置指定元素获取焦点
                //return false ;  //不能结束if,只是结束msg函数.
            });
            /*floginacct.focus();
            floginacct.val("");*/
            return false;
        }
       $.ajax({
            type : "POST",
            data : {
                "loginacct" : floginacct.val(),
                "userpswd" : fuserpswd.val(),
                "type" : ftype.val(),
                "remberme" : flag?"1":"0"
            },
            /*dataType: "json",
            async : false,*/
            url : "${APP_PATH}/doLogin.do",
            beforeSend : function () {
                layer.msg("处理中", {icon:16});
                //一般做表单数据校验
            },
            success : function (ajaxResult) { //{"success":true} 或 {"success":false,"message":"登录失败！！！"}
                if (ajaxResult.success){
                    var data = ajaxResult.data;
                    var url = location.href;
                    var mark = url.substring(url.indexOf("?")+1,url.length);
                    if ("member"==data){
                        if(mark=="mark=1"){
                            window.location.href="${APP_PATH}/project/start.htm";
                        }else
                        window.location.href="${APP_PATH}/member/member.htm";
                    }else if("user"==data){
                        window.location.href="${APP_PATH}/main.htm";
                    }else{
                        layer.msg("登录类型不合法!", {time:1000, icon:5, shift:6});
                    }
                } else{
                    /*alert(ajaxResult.success);*/
                    layer.msg("登录失败!", {time:1000, icon:5, shift:6});
                }
            },
            error : function () {
                alert("error");
            }
        });

        $("#loginForm").submit();
        /*var type = $(":selected").val();
        if ( type == "user" ) {
            window.location.href = "main.html";
        } else {
            window.location.href = "index.html";
        }*/
    }

controller的代码

 @RequestMapping("/doLogin")
    public AjaxResult doLogin(String loginacct, String userpswd, String type, String remberme, HttpSession session, HttpServletResponse response){
        AjaxResult ajaxResult = new AjaxResult();
        try {
            Map<String,Object> paramMap = new HashMap<String,Object>();
            response.setContentType("text/html;charset=utf-8");
            paramMap.put("loginacct", loginacct);
            paramMap.put("userpswd",MD5Util.digest(userpswd));
            System.out.println(MD5Util.digest(userpswd));
            paramMap.put("type", type);
            if("member".equals(type)){
                Member member = memberService.queryMemeberlogin(paramMap);
                if(member!=null){
                    ajaxResult.setSuccess(true);
                }else{
                    ajaxResult.setSuccess(false);
                }
                System.out.println(member);
                session.setAttribute(Const.LOGIN_MEMBER,member);
                if ("1".equals(remberme)){
                    //"loginacct=xxxxx&userpswd=xxxxxx&logintype=member"
                  String logincode = "\"loginacct="+member.getLoginacct()+"&userpswd="+member.getUserpswd()+"&logintype=member\"";
                    System.out.println("用户存放到Cookie中的键值对：logincode:::::::"+logincode);
                    Cookie c = new Cookie("logincode",logincode);
                    c.setMaxAge(60*60*24*14);
                    //如果设置为“/”，则本域名下contextPath都可以访问该Cookie。注意最后一个字符必须为“/”
                    c.setPath("/");
                    response.addCookie(c);
                }
            }else if("user".equals(type)){
                User user = userService.queryUserlogin(paramMap);
                session.setAttribute(Const.LOGIN_USER, user);
                if(user!=null){
                    ajaxResult.setSuccess(true);
                }
                if ("1".equals(remberme)){
                 String logincode = "\"loginacct="+user.getLoginacct()+"&userpswd="+user.getUserpswd()+"&logintype=user\"";
                    System.out.println("用户存放到Cookie中的键值对：logincode:::::::"+logincode);
                    Cookie c = new Cookie("logincode",logincode);
                    c.setMaxAge(60*60*24*14);
                    c.setPath("/");
                    response.addCookie(c);
                }
                //---------------------------------------------------------------
                //加载当前登录用户的所拥有的许可权限.
                /*User user = (User)session.getAttribute(Const.LOGIN_USER);*/
                List<Permission> myPermissions = userService.queryPermissionByUserid(user.getId());
                Permission permissionRoot = null;
                Map<Integer,Permission> map = new HashMap<Integer,Permission>();
                Set<String> myUrls = new HashSet<String>();//用于拦截器拦截许可权限
                for (Permission innerpermission : myPermissions) {
                    map.put(innerpermission.getId(), innerpermission);
                    myUrls.add("/"+innerpermission.getUrl());
                }
                session.setAttribute(Const.MY_URIS,myUrls);
                for (Permission permission : myPermissions) {
                    //通过子查找父
                    //子菜单
                    Permission child = permission ; //假设为子菜单
                    if(child.getPid() == null ){
                        permissionRoot = permission;
                    }else{
                        //父节点
                        Permission parent = map.get(child.getPid());
                        parent.getChildren().add(child);
                    }
                }
                session.setAttribute("permissionRoot", permissionRoot);
                //---------------------------------------------------------------
            }else{
            }
            ajaxResult.setData(type);
            //返回的json串为   {"success":true}
        }catch (Exception e){
            ajaxResult.setMessage("登录失败！！！");
            /*e.printStackTrace();*/
            ajaxResult.setSuccess(false);
            //返回的json串为    {"success":false,"message":"登录失败！！！"}
        }
        return ajaxResult;
    }