简单解释分页

故名思意：就是把过多的数据进行整理，让过于臃肿的数据分开展示，用分页分开数据，可以提高用户观看体验等等

在java中实现的方法

public List paging(int pageindex,String str) throws SQLException{
    list=new ArrayList<>();
    int pageSize=5;
    int start=(pageindex-1)*pageSize;
    con=DBhelper.getCon();
    sql="select * from news where title like '%"+str+"%' and nid limit ?,?";
    ps=con.prepareStatement(sql);
    ps.setObject(1, start);
    ps.setObject(2, pageSize);
    rs=ps.executeQuery();
    while(rs.next()) {
        news=new News(rs.getInt("nid"),rs.getInt("sid"),rs.getString("title"),rs.getString("author"),
                rs.getString("summary"),rs.getString("content"),rs.getString("content"),rs.getString("addtime"));
        list.add(news);
    }
    DBhelper.colseObj(con, ps, rs);
    return list;
}


public int getMaxPage(String str) throws SQLException {
    con=DBhelper.getCon();
    sql="select count(0) from news where title like '%"+str+"%'";
    ps=con.prepareStatement(sql);
    rs=ps.executeQuery();
    if(rs.next()) {
            maxPage=rs.getInt(1)/5;
            if (rs.getInt(1)%5!=0) {
                maxPage++;
            }
    }
    return maxPage;
}

在sql语句中实现的方法

select * from (select a.*,rownum myid from 表名) b where myid between ? and ?；