thinkphp缓存使用实例写法

以下是thinkphp缓存实例写法
$newslist = "";
if(C('CATCH')) {
    $newslist = S('newslist');
}
if(!$newslist){
    $news = M('news');
    $news_data['cat_id'] = array('eq',1);
    $newslist = $news->where($news_data)->limit(10)->select();
    unset($news,$news_data);
    S('newslist',$newslist,C('CATCH_TIME')*24*60*60);
}

注意：
C('CATCH')和C('CATCH_TIME')是缓存开启的状态和缓存时间