php实现静态缓存类

class File
{
    private $_dir;
    const EXT = '.txt';
    
    public function __construct()
    {
        $this->_dir = dirname(__FILE__).'/files';
    }

    public function cacheData($key, $value='', $path = ''){

        # 拼接文件名
        $filename = $this->_dir.$path.'/'.$key.self::EXT;

        # 写入缓存
        if ($value !== '') {

            # 删除缓存
            if (is_null($value)) {
                return unlink($filename);
            }
            
            $dir = dirname($filename);

            # 判断目录是否存在
            if (!is_dir($dir)) {
                mkdir($dir,0777);
            }

            return file_put_contents($filename, json_encode($value));

        # 读取缓存    
        }else{

            if (!is_file($filename)) {
                return false;
            }else{

                # 解析json字符串并返回
                return json_decode(file_get_contents($filename),true);
            }
        }
    }
}

$file = new File;

$data['id'] = 1;
$data['name'] = 'yach';
$data['data'][] = 1;
$data['data'][] = 3;
$data['data']['msg'] = 'helloword';

# 添加
$file->cacheData('test',$data);

# 读取
$file->cacheData('test');

# 删除
$file->cacheData('test',null);