前端代码：

    //保存
    function save(event) {
        $(event).button("loading");
        $.ajax({
            url: "${base}/platform/book/noth/addDo",
            data: JSON.stringify({
                "list": JSON.stringify($('#mainbody').tableinputtoJson())
            }),
            success: function (data) {
                $(event).button("reset");
                if (data.code === 0) {
                    Toast.success(data.msg);
                    $(this).modal('hide');
                } else {
                    Toast.error(data.msg);
                }
            },
            dataType: "json",
            type: "POST",
            contentType: 'application/json'
        });
    }

后台：

    @At("/addDo")
    @Ok("json")
    @AdaptBy(type = JsonAdaptor.class)
    @RequiresPermissions("platform.book.noth.add")
    public Object addDo(@Param("list")List<Book_noth> maximums, HttpServletRequest req) {
        try {
            List<Book_noth> listForSave = new ArrayList<>();
            if (null != maximums && !maximums.isEmpty()) {
                for (Book_noth maximum : maximums) {
                    if (null != maximum.getMaximum()) {
                        listForSave.add(maximum);
                    }
                }
                bookNothService.dao().insert(listForSave);
            }
            return Result.success("system.success");
        } catch (Exception e) {
            return Result.error("system.error");
        }
    }

后台for循环那里报的错