一：读取数据库方式开发首页接口原理图  从数据库获取信息--->>>>封装------>>>生成接口数据  备注：运用场景[数据时性比较高的系统]二：代码实现(1)list.php
     cacheData('index_cron_cahce');if($data) {    return Response::show(200, '首页数据获取成功', $data);}else{    return Response::show(400, '首页数据获取失败', $data);}exit;require_once('./db.php');require_once('./file.php');$page = isset($_GET['page']) ? $_GET['page'] : 1;$pageSize = isset($_GET['pagesize']) ? $_GET['pagesize'] : 6;if(!is_numeric($page) || !is_numeric($pageSize)) {    return Response::show(401, '数据不合法');}$offset = ($page - 1) * $pageSize;$sql = "select * from video where status = 1 order by orderby desc limit ". $offset ." , ".$pageSize;$cache = new File();$videos = array();if(!$videos = $cache->cacheData('index_mk_cache' . $page .'-' . $pageSize)) {    echo 1;exit;    try {        $connect = Db::getInstance()->connect();    } catch(Exception $e) {        // $e->getMessage();        return Response::show(403, '数据库链接失败');    }    $result = mysql_query($sql, $connect);         while($video = mysql_fetch_assoc($result)) {        $videos[] = $video;    }    if($videos) {        $cache->cacheData('index_mk_cache' . $page .'-' . $pageSize, $videos, 1200);    }}if($videos) {    return Response::show(200, '首页数据获取成功', $videos);} else {    return Response::show(400, '首页数据获取失败', $videos);}-------------------------response.php-------------
      $code,            'message' => $message,            'data' => $data,        );        if($type == 'json') {            self::json($code, $message, $data);            exit;        } elseif($type == 'array') {            var_dump($result);        } elseif($type == 'xml') {            self::xmlEncode($code, $message, $data);            exit;        } else {            // TODO        }    }    /**    * 按json方式输出通信数据    * @param integer $code 状态码    * @param string $message 提示信息    * @param array $data 数据    * return string    */    public static function json($code, $message = '', $data = array()) {                if(!is_numeric($code)) {            return '';        }        $result = array(            'code' => $code,            'message' => $message,            'data' => $data        );        echo json_encode($result);        exit;    }    /**    * 按xml方式输出通信数据    * @param integer $code 状态码    * @param string $message 提示信息    * @param array $data 数据    * return string    */    public static function xmlEncode($code, $message, $data = array()) {        if(!is_numeric($code)) {            return '';        }        $result = array(            'code' => $code,            'message' => $message,            'data' => $data,        );        header("Content-Type:text/xml");        $xml = "
     \n";        $xml .= "
     
      \n";        $xml .= self::xmlToEncode($result);        $xml .= "
     ";        echo $xml;    }    public static function xmlToEncode($data) {        $xml = $attr = "";        foreach($data as $key => $value) {            if(is_numeric($key)) {                $attr = " id='{
   $key}'";                $key = "item";            }            $xml .= "<{
   $key}{
   $attr}>";            $xml .= is_array($value) ? self::xmlToEncode($value) : $value;            $xml .= "
     \n";        }        return $xml;    }}-----------------file.php-------------------
     _dir = dirname(__FILE__) . '/files/';    }    public function cacheData($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');