静态缓存

<?php

class File {
private $_dir;

const EXT = '.txt';

public function __construct() {
$this->_dir = dirname(__FILE__) . '/files/';
}
public function cacheData($key, $value = '', $cacheTime = 0) {
$filename = $this->_dir . $key . self::EXT;

if($value !== '') { // 将value值写入缓存
if(is_null($value)) {
return @unlink($filename);
}
$dir = dirname($filename);
if(!is_dir($dir)) {
mkdir($dir, 0777);
}

$cacheTime = sprintf('%011d', $cacheTime);
return file_put_contents($filename,$cacheTime . json_encode($value));
}

if(!is_file($filename)) {
return FALSE;
}
$contents = file_get_contents($filename);
$cacheTime = (int)substr($contents, 0 ,11);
$value = substr($contents, 11);
if($cacheTime !=0 && ($cacheTime + filemtime($filename) < time())) {
unlink($filename);
return FALSE;
}
return json_decode($value, true);

}
}

$file = new File();

echo $file->cacheData('test1');