PHP实现的简单缓存类

本文实例讲述了PHP实现的简单缓存类。分享给大家供大家参考。具体如下：

cache.inc.php：

dir_isvalid($dir)) {
      $this->dir = $dir;
      $this->lifetime = $lifetime;
      $this->ext = '.Php';
      $this->cacheid = $this->getcacheid();
    }
  }
  
  private function isvalid() {
    if (!file_exists($this->cacheid)) return false;
    if (!(@$mtime = filemtime($this->cacheid))) return false;
    if (mktime() - $mtime > $this->lifetime) return false;
    return true;
  }
  
  public function write($mode=0,$content='') {
    switch ($mode) {
      case 0:
 $content = ob_get_contents();
 break;
      default:
 break;
    }
    ob_end_flush();
    try {
      file_put_contents($this->cacheid,$content);
    }
    catch (Exception $e) {
      $this->error('写入缓存失败!请检查目录权限!');
    }
  }
  
  public function load() {
    if ($this->isvalid()) {
      echo "This is Cache. ";
      //以下两种方式,哪种方式好?????
      require_once($this->cacheid);
      //echo file_get_contents($this->cacheid);
      exit();
    }
    else {
      ob_start();
    }
  }
  
  public function clean() {
    try {
      unlink($this->cacheid);
    }
    catch (Exception $e) {
      $this->error('清除缓存文件失败!请检查目录权限!');
    }
  }
  
  private function getcacheid() {
    return $this->dir.md5($this->geturl()).$this->ext;
  }
  
  private function dir_isvalid($dir) {
    if (is_dir($dir)) return true;
    try {
      mkdir($dir,0777);
    }
    catch (Exception $e) {
$this->error('所设定缓存目录不存在并且创建失败!请检查目录权限!');
return false;      
    }
    return true;
  }
  
  private function geturl() {
    $url = '';
    if (isset($_SERVER['REQUEST_URI'])) {
      $url = $_SERVER['REQUEST_URI'];
    }
    else {
      $url = $_SERVER['Php_SELF'];
      $url .= empty($_SERVER['QUERY_STRING'])?'':'?'.$_SERVER['QUERY_STRING'];
    }
    return $url;
  }
  
  private function error($str) {
    echo ''.$str.'';
  }
}
?>

demo.php：

load(); //装载缓存,缓存有效则不执行以下页面代码
  //页面代码开始
  echo date('H:i:s jS F');
  //页面代码结束
  $cache->write(); //首次运行或缓存过期,生成缓存
//Demo2:
  require_once('cache.inc.php');
  $cachedir = './Cache/'; //设定缓存目录
  $cache = new Cache($cachedir,10); //省略参数即采用缺省设置, $cache = new Cache($cachedir);
  if ($_GET['cacheact'] != 'rewrite') //此处为一技巧,通过xx.Php?cacheact=rewrite更新缓存,以此类推,还可以设定一些其它操作
    $cache->load(); //装载缓存,缓存有效则不执行以下页面代码
  //页面代码开始
  $content = date('H:i:s jS F');
  echo $content;
  //页面代码结束
  $cache->write(1,$content); //首次运行或缓存过期,生成缓存
//Demo3:
  require_once('cache.inc.php');
  define('CACHEENABLE',true);
  if (CACHEENABLE) {
    $cachedir = './Cache/'; //设定缓存目录
    $cache = new Cache($cachedir,10); //省略参数即采用缺省设置, $cache = new Cache($cachedir);
    if ($_GET['cacheact'] != 'rewrite') //此处为一技巧,通过xx.Php?cacheact=rewrite更新缓存,以此类推,还可以设定一些其它操作
      $cache->load(); //装载缓存,缓存有效则不执行以下页面代码  
  }
  //页面代码开始
  $content = date('H:i:s jS F');
  echo $content;
  //页面代码结束
  if (CACHEENABLE)
    $cache->write(1,$content); //首次运行或缓存过期,生成缓存
?>

希望本文所述对大家的php程序设计有所帮助。