php生成静态页面

<?php
/**
 * Created by PhpStorm.
 * User: s
 * Date: 2018/11/3
 * Time: 8:33
 */
class PdoClass
{
    protected $_pdo;
    public function __construct()
    {
        $this->_pdo = new PDO("mysql:host=127.0.0.1;dbname=student","root","root");
    }
    //分页
    public function fen_ye($page)
    {
        $count1=$this->_pdo->query("select count(*) from news")->fetchColumn();
       $tiao=3;
       $zong_page=ceil($count1/$tiao);
      // return $zong_page;
       $limit=($page-1)*$tiao;
       $sql="select * from news limit $limit, $tiao";
       $re= $this->_pdo->query($sql)->fetchAll();
       $show['shou_page']=1;
       $show['shang_page']=$page-1<1?1:$page-1;
       $show['xia_page']=$page+1>$zong_page?$zong_page:$page+1;
       $show['zong_page']=$zong_page;
       $list=['re'=>$re,'show'=>$show];
       return $list;
    }
    //查询多条
    public function sele($title='')
    {
        if(!empty($title))
        {
            $sql="select * from news where title LIKE '%$title%'";
            return $this->_pdo->query($sql)->fetchAll();
        }
        $sql="select * from news";
        return $this->_pdo->query($sql)->fetchAll();
    }
    //查询单条
    public function getsel($id)
    {
        $sql="select * from news where id='$id'";
        return $this->_pdo->query($sql)->fetch();
    }
    //删除
    public function delete($id)
    {
        $sql="delete from news where id=$id";
        $this->_pdo->exec($sql);
        return true;
    }
    //添加
    public function add($title,$content,$time)
    {
        $sql="insert into news VALUES (null,$title,$content,$time)";
        $this->_pdo->exec($sql);
        return true;
    }
    //修改
    public function update($id,$title,$content)
    {
        $sql="update news set title='$title',content='$content' where id='$id'";
        $this->_pdo->exec($sql);
        return true;
    }
    //静态化
    public function obhtml($id,$title,$content)
    {
        ob_start();
        include "show.html";
        $text=ob_get_clean();
        $shu_ru='./html/'.$id.'.html';
        if(file_exists($shu_ru))
        {
            $filec_time=filectime($shu_ru);//文件创建时间
            if(time()-$filec_time<20)//没有过期
            {
                echo "自动生成静态页面";
                file_put_contents($shu_ru,$text);
            }
            else//过期
            {
                unlink($shu_ru);//删除过期文件
                ob_start();
                echo "这是过期后生成的静态页面";
                file_put_contents($shu_ru,$text);
            }
        }

    }
}