redis 实现分页：报错

redis存储数据，然后mysql维护id，分页在mysql上做好，然后获取数据从redis中获取

    default PageBuilder paginate(int pageNumber) {
        if (pageNumber <= 0) {
            pageNumber = 1;
        }

        // 每页大小
        int pageSize = Sys.PAGE_SIZE;
        // 总数据
        int totalRow = this.zcard().intValue();
        // 总页数
        int totalPage = (int) (totalRow / pageSize);
        if (totalRow % pageSize != 0) {
            totalPage++;
        }

        if (pageNumber > totalPage) {
            pageNumber = totalPage;
        }

        PageBuilder builder = new PageBuilder();
        builder.setPageNumber(pageNumber);
        builder.setPageSize(pageSize);
        builder.setTotalPage(totalPage);
        builder.setTotalRow(totalRow);

        int start = (pageNumber - 1) * pageSize;
        int end = pageNumber * pageSize - 1;

        Set<Object> ids = this.zrange(start, end);

        builder.setIds(ids);

        return builder;
    }