protected void pageByYear(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       System.out.println("经过了前台的byueservlet程序");
       //1.获取请求的参数pageNo和pageSize
       int pageNo = WebUtils.parseInt(req.getParameter("pageNo"),1);
       int pageSize = WebUtils.parseInt(req.getParameter("pageSize"), Page.PAGE_SIZE);
       int min = WebUtils.parseInt(req.getParameter("min"),0);
       int max = WebUtils.parseInt(req.getParameter("max"),Integer.MAX_VALUE);
       //2.调用BuyeService.page(pageNo,pageSize);page对象
       Page<Byue> page = byueService.pageByYear(pageNo,pageSize,min,max);

       StringBuffer sb = new StringBuffer("clientByueServlet?action=pageByYear");
       //如果有最小值参数，追加到分页条的地址参数中
       if(req.getParameter("min")!=null){
           sb.append("&min=").append(req.getParameter("min"));
       }
       //如果有最大值参数，追加到分页条的地址参数中
       if(req.getParameter("max")!=null){
           sb.append("&max=").append(req.getParameter("max"));
       }
       page.setUrl(sb.toString());
       //3.保存到request域中
       req.setAttribute("page",page);
       //4.请求转发
       req.getRequestDispatcher("/pages/home.jsp").forward(req,resp);
   }

public Page<Byue> pageByYear(int pageNo, int pageSize, int min, int max) {
       Page<Byue> page = new Page<Byue>();

       //设置每页显示的数量
       page.setPageSize(pageSize);
       //求总记录数
       Integer pageTotalCount = byueDao.querForPageTotalCountByYear(min,max);
       //设置总记录数
       page.setPageTotalCount(pageTotalCount);
       //求总页码
       Integer pageTotal = pageTotalCount / pageSize;
       if (pageTotalCount % pageSize > 0 ){
           pageTotal+=1;
       }
       //设置总页码
       page.setPageTotal(pageTotal);
       /*数据边界的有效检查 在page.java中直接检查*/

       //设置当前页码
       page.setPageNo(pageNo);

       int begin = (page.getPageNo()-1) * pageSize;
       //求当前页数据
       List<Byue> items = byueDao.querForPageItemsByYear(begin,pageSize,min,max);
       //设置当前页数据
       page.setItem(items);

       return page;
   }

@Override
public Integer querForPageTotalCountByYear(int min, int max) {
    String sql = "select count(*) from s_by where year between ? and ?";
    Number count = (Number)queryForSingleValue(sql,min,max);
    return count.intValue();
}

@Override
public List<Byue> querForPageItemsByYear(int begin, int pageSize, int min, int max) {
    String sql = "select `id`,`name`,`sclass`,`bm`, `zw`, `year`,`img_path` imgPath " +
            "from s_by where year between ? and ? order by year limit ?,?";
    return queryForyList(Byue.class,sql,min,max,begin,pageSize);
}