三种缓存方式的详解

1.文件缓存

一般情况下我们都将数据先缓存在文件当中，当需要的时候直接从文件中读取。则可以减少数据库查询的压力。

class File{

         private$_dir;

 

         constEXT = '.txt';

 

         publicfunction __construct(){

                   $dir= str_replace('\\', '/', dirname(__FILE__));

                   $this->_dir= $dir.'/files/';

         }

 

         /**

          * $value==null时删除缓存

          *

          */

         publicfunction cacheData($key,$value='',$cacheTime=0){

                   $filename= $this->_dir.$key.self::EXT;

                   //echo$filename;exit;

                   $dir= dirname($filename);

 

                   if(is_null($value)){//删除缓存

                            return unlink($filename);

                   }

 

                   if($value!= ''){//添加缓存

 

                            if(!is_dir($dir)){

                                     mkdir($dir,0777);

                            }

 

                            if(file_put_contents($filename,json_encode($value),FILE_APPEND ) !== false){

                                     echo 'succeed';

                            }

 

                   }else{

                            //查询缓存

                            if(!is_file($filename)){

                                     return false;

                            }else{

                                     return json_decode(file_get_contents($filename),true);

                            }

                           

                   }       

                  

         }

}

//测试案例

$file = new File();

 

$result = array(

                            'code'=> '555',

                            'message'=> 'message'

                   );

 

if($res =$file->cacheData('first',null)){

         print_r($res);exit;

         echo 'succeed';

}else{

         echo 'fail';

}

redis的安装和使用

1.安装redis

Yum -y install redis

2.  安装php-redis扩展

yum install php-redis

3.  启动redis，并设定开机自动启动

service redis start

chkconfig redis on

 

4.开启终端

Redis-cli

<?php

         $redis= new Redis();

         $redis->connect('127.0.0.1',6379);

         $redis->set('leyan',123);

         echo $redis->get('leyan');

 

$redis->setex('leyan',12,'haha');//设置12秒内的存储