PHP数据缓存

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缓存技术是web开发用来提高网站访问速度和减缓服务器压力的的重要手段之一，缓存主要分为页面缓存和数据缓存，一般情况下首页都采用页面缓存技术，其他的一些页面采用数据缓存比较多。下面贴上最近用php实现的数据缓存代码

cache.php

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<?php
class Cache {
private $cache_path;//path for the cache
private $cache_expire;//seconds that the cache expires
//cache constructor, optional expiring time and cache path
function __construct($exp_time=3600,$path=”cache/”){
$this->cache_expire=$exp_time;
$this->cache_path=$path;
}
//returns the filename for the cache
private function fileName($key){
return $this->cache_path.md5($key);
}
//creates new cache files with the given data, $key== name of the cache, data the info/values to store
public function put($key, $data){
$values = serialize($data);
$filename = $this->fileName($key);
$file = fopen($filename, ‘w’);
    if ($file){//able to create the file
        fwrite($file, $values);
        fclose($file);
          return true;
    }
    else return false;
}
//returns cache for the given key
public function get($key){
$filename = $this->fileName($key);
if (!file_exists($filename) || !is_readable($filename)){//can’t read the cache
return false;
}
if ( time() < (filemtime($filename) + $this->cache_expire) ) {//cache for the key not expired
$file = fopen($filename, “r”);// read data file
        if ($file){//able to open the file
            $data = fread($file, filesize($filename));
            fclose($file);
            return unserialize($data);//return the values
        }
        else return false;
}
else return false;//was expired you need to create new
  }
}
?>

调用方法（完整列子）：

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function get_cache_data($key){
      //从缓存从读取键值 $key 的数据
      $values = $this->data_cache->get($key);
      //返回读取结果
      return $values;
    }
    function put_cache_data($key,$data){
      //insert code here…
      //写入键值 $key 的数据
      $is_write = $this->data_cache->put($key, $data);
      return $is_write;
    }
    /**
      * 最新成交列表
      */
    public function get_lastbargainlist()
    {
      $list_xml = $this->get_cache_data(“lastbargainlist”);
      if(!$list_xml){
        $list_xml = $this->soap_client->doRequest($this->request_xml(“HS”,”lastbargainlist”));
        if(!$this->put_cache_data(“lastbargainlist”,$list_xml)){
          // echo “<script> alert(‘失败！’); </script>”;
        }
      }
      $list_arr = simplexml_load_string($list_xml);
      return $list_arr;
    }

实现页面缓存需要用到 ob_start ob_get_content ob_clean等函数，下次有需要的时候再去实现