读取设置memcache的值（优先支持memcached扩展和cas协议）

addServer($INI['memcachehost'], $INI['memcacheport']);
				$res['value'] = $m1->get($key, null, $cas);
				$res['cas'] = $cas;
			}
			else
			{
				$m1 = self::getinstance();
				$m1->addServer($INI['memcachehost'], $INI['memcacheport']);
				$res['value'] = $m1->get($key);
			}
			return $res;
		}

		static public function set($key,$value,$cas)
		{
			$value = (string)$value;
			global $INI;
			if(class_exists('Memcached'))
			{
				$m1 = self::getinstance();
				$m1->addServer($INI['memcachehost'], $INI['memcacheport']);
				$res = $m1->cas($cas,$key,$value);
			}
			else
			{
				$m1 = self::getinstance();
				$m1->addServer($INI['memcachehost'], $INI['memcacheport']);
				$res = $m1->set($key,$value);
			}
			return $res;
		}
	}