public function behaviors()
{
    return [
        [
            'class' => 'yii\filters\PageCache',
            'only' => ['index'],
            'duration' => 60,
            'variations' => [
                \Yii::$app->language,
            ],
            'dependency' => [
                'class' => 'yii\caching\DbDependency',
                'sql' => 'SELECT COUNT(*) FROM post',
            ],
        ],
    ];
}

public function beforeAction($action)
    {
        if (!$this->enabled) {
            return true;
        }
        $this->cache = Instance::ensure($this->cache, 'yii\caching\CacheInterface'); //这里调用cache接口
        if (is_array($this->dependency)) {
            $this->dependency = Yii::createObject($this->dependency);
        }
        $response = Yii::$app->getResponse();
        $data = $this->cache->get($this->calculateCacheKey());
        if (!is_array($data) || !isset($data['cacheVersion']) || $data['cacheVersion'] !== static::PAGE_CACHE_VERSION) {
            $this->view->pushDynamicContent($this);
            ob_start();
            ob_implicit_flush(false);
            $response->on(Response::EVENT_AFTER_SEND, [$this, 'cacheResponse']);
            Yii::debug('Valid page content is not found in the cache.', __METHOD__);
            return true;
        }
        $this->restoreResponse($response, $data);
        Yii::debug('Valid page content is found in the cache.', __METHOD__);
        return false;
    }

'cache' => [
            'class' => 'yii\caching\FileCache',
        ],

/**
     * Stores a value identified by a key in cache.
     * This is the implementation of the method declared in the parent class.
     *
     * @param string $key the key identifying the value to be cached
     * @param string $value the value to be cached. Other types (If you have disabled [[serializer]]) unable to get is
     * correct in [[getValue()]].
     * @param int $duration the number of seconds in which the cached value will expire. 0 means never expire.
     * @return bool true if the value is successfully stored into cache, false otherwise
     */
    protected function setValue($key, $value, $duration)
    {
        $this->gc(); //垃圾回收
        $cacheFile = $this->getCacheFile($key);
        if ($this->directoryLevel > 0) {
            @FileHelper::createDirectory(dirname($cacheFile), $this->dirMode, true);
        }
        // If ownership differs the touch call will fail, so we try to
        // rebuild the file from scratch by deleting it first
        // https://github.com/yiisoft/yii2/pull/16120
        if (is_file($cacheFile) && function_exists('posix_geteuid') && fileowner($cacheFile) !== posix_geteuid()) {
            @unlink($cacheFile);
        }
        if (@file_put_contents($cacheFile, $value, LOCK_EX) !== false) {
            if ($this->fileMode !== null) {
                @chmod($cacheFile, $this->fileMode);
            }
            if ($duration <= 0) {
                $duration = 31536000; // 1 year
            }
            return @touch($cacheFile, $duration + time());
        }
        $error = error_get_last();
        Yii::warning("Unable to write cache file '{$cacheFile}': {$error['message']}", __METHOD__);
        return false;
    }

/**
     * Removes expired cache files.
     * @param bool $force whether to enforce the garbage collection regardless of [[gcProbability]].
     * Defaults to false, meaning the actual deletion happens with the probability as specified by [[gcProbability]].
     * @param bool $expiredOnly whether to removed expired cache files only.
     * If false, all cache files under [[cachePath]] will be removed.
     */
    public function gc($force = false, $expiredOnly = true)
    {
        if ($force || mt_rand(0, 1000000) < $this->gcProbability) {
            $this->gcRecursive($this->cachePath, $expiredOnly);
        }
    }

'cache' => [
            'class' => 'yii\caching\FileCache',
            'gcProbability'=>10000
        ],

Yii::$app->cache->gc(true);