1 说明前段时间面试的时候，一直被问到如何设计一个秒杀活动，但是无奈没有此方面的实际经验，所以只好凭着自己的理解和一些资料去设计这么一个程序主要利用到了redis的string和set,string主要是利用它的k-v结构去对库存进行处理，也可以用list的数据结构来处理商品的库存，set则用来确保用户进行重复的提交其中我们最主要解决的问题是-防止并发产生超抢/超卖
2 流程设计
3 代码3.1 服务端代码class MiaoSha{ const MSG_REPEAT_USER = '请勿重复参与'; const MSG_EMPTY_STOCK = '库存不足'; const MSG_KEY_NOT_EXIST = 'key不存在'; const IP_POOL = 'ip_pool'; const USER_POOL = 'user_pool'; /** @var Redis */ public $redis; public $key; public function __construct($key = '') { $this->checkKey($key); $this->redis = new Redis(); //todo 连接池 $this->redis->connect('127.0.0.1'); } public function checkKey($key = '') { if(!$key) { throw new Exception(self::MSG_KEY_NOT_EXIST); } else { $this->key = $key; } } public function setStock($value = 0) { if($this->redis->exists($this->key) == 0) { $this->redis->set($this->key,$value); } } public function checkIp($ip = 0) { $sKey = $this->key . self::IP_POOL; if(!$ip || $this->redis->sIsMember($sKey,$ip)) { throw new Exception(self::MSG_REPEAT_USER); } } public function checkUser($user = 0) { $sKey = $this->key . self::USER_POOL; if(!$user || $this->redis->sIsMember($sKey,$user)) { throw new Exception(self::MSG_REPEAT_USER); } } public function checkStock($user = 0, $ip = 0) { $num = $this->redis->decr($this->key); if($num < 0 ) { throw new Exception(self::MSG_EMPTY_STOCK); } else { $this->redis->sAdd($this->key . self::USER_POOL, $user); $this->redis->sAdd($this->key . self::IP_POOL, $ip); //todo add to mysql echo 'success' . PHP_EOL; error_log('success' . $user . PHP_EOL,3,'/var/www/html/demo/log/debug.log'); } } /** * @note:此种做法不能防止并发 * @func checkStockFail * @param int $user * @param int $ip * @throws Exception */ public function checkStockFail($user = 0,$ip = 0) { $num = $this->redis->get($this->key); if($num > 0 ){ $this->redis->sAdd($this->key . self::USER_POOL, $user); $this->redis->sAdd($this->key . self::IP_POOL, $ip); //todo add to mysql echo 'success' . PHP_EOL; error_log('success' . $user . PHP_EOL,3,'/var/www/html/demo/log/debug.log'); $num--; $this->redis->set($this->key,$num); } else { throw new Exception(self::MSG_EMPTY_STOCK); } }}3.2 客户端测试代码function test(){ try{ $key = 'cup_'; $handler = new MiaoSha($key); $handler->setStock(10); $user = rand(1,10000); $ip = $user; $handler->checkIp($ip); $handler->checkUser($user); $handler->checkStock($user,$ip); } catch (\Exception $e) { echo $e->getMessage() . PHP_EOL; error_log('fail' . $e->getMessage() .PHP_EOL,3,'/var/www/html/demo/log/debug.log'); }}function test2(){ try{ $key = 'cup_'; $handler = new MiaoSha($key); $handler->setStock(10); $user = rand(1,10000); $ip = $user; $handler->checkIp($ip); $handler->checkUser($user); $handler->checkStockFail($user,$ip); //不能防止并发的 } catch (\Exception $e) { echo $e->getMessage() . PHP_EOL; error_log('fail' . $e->getMessage() .PHP_EOL,3,'/var/www/html/demo/log/debug.log'); }}4 测试测试环境说明
...