java仿百度假分页代码实现的详解

integer start = (pagenum - 1 ) * pagesize;

     integer end = pagesize;

     list<entity> entitylist;

     //调用mapper查询数据库

     entitylist = entitypomapper.query(start, end);

     simplepageinfo simplepageinfo = simplepageinfo.of(entitylist );

     simplepageinfo.setnumber(pagenum);

     simplepageinfo.setpagesize(pagesize);

// 查询出来数据等于size,总数据量加一，页数加一

     if (entitylist .size() == pagesize) {

       integer totalelements = (pagenum * pagesize) + 1 ;

       integer pages = pagenum + 1 ;

       simplepageinfo.settotalelements(totalelements);

       simplepageinfo.setpages(pages);

     } else {

     //数据不够size

       integer totalelements = ((pagenum - 1 ) * pagesize + entitylist .size());

       integer pages = pagenum;

       simplepageinfo.settotalelements(totalelements);

       simplepageinfo.setpages(pages);

     }

     return simplepageinfo;

}

<select .............>

     select..

     from ...

     where ...

     limit #{start}, #{end}

   </select>