Java秒杀系统优化(高性能高并发)

朱雀 2023-06-16 15:55 88阅读 0赞

**源码免费下载地址：关注微信公众号“****虾米聊吧****”，回复关键字“****秒杀****”**

主题：在**大并发**，**大流量**的情况下如何提升吞吐量或者说QPS？

而秒杀活动恰恰就是属于大并发的情形，因此下面简单来谈谈大并发下秒杀方案的优化。

**项目采用技术：SpringBoot + MyBatis + MySql + RabbitMq + Redis**

**RabbitMq安装参考：**[https://blog.csdn.net/zwx19921215/article/details/103255834][https_blog.csdn.net_zwx19921215_article_details_103255834]

**文章首先说明优化思路方案和步骤，然后阐述代码具体实现，最后采用JMeter进行简单压测。**

*  **针对大并发的主体优化常见有如下几种方式：**

1.页面缓存 + URL缓存 + 对象级缓存

2.页面静态化（浏览器缓存）,前后端分离+ajax

3.静态资源优化（js/css压缩，减少流量），多个js/css组合，减少连接数

4.CDN优化

而作为一个程序猿我们都知道**并发最大的瓶颈基本就是数据库**，**因此最好就是减少数据库的访问次数**即加缓存。

*  **从访问开始到后端返回整个缓存链可以是：**

**浏览器端缓存（页面静态化）--> CDN --> nginx缓存 --> 后端服务缓存(页面缓存、对象级缓存等) --> 数据库**

而作为一名后端工程师的优化则主要是针对**接口优化**，这也是我们的重头戏；

*  **接口优化大概通过如下步骤处理：**

1.redis预减库存减少 数据库访问

2.内存标记减少redis访问

3.请求先入队缓冲，异步下单 ，增强用户体验

*  **针对秒杀接口优化：**

**核心思路：减少数据库访问（数据库瓶颈）**

1.系统初始化，把商品库存数量加载到redis

2.收到请求，redis预减库存，库存不足，直接返回，否则进入3

3.请求入队，立即返回 排队中

4.请求出队，生成订单，减少库存

5.客户端轮询，是否秒杀成功

*  **针对安全方面优化：**

1.秒杀接口地址隐藏

2.数学公式验证码

3.接口限流防刷

*  **秒杀接口地址隐藏：**

**思路：****秒杀开始之前，先去请求接口获取秒杀地址 **

1.接口改造 ，带上PathVariable参数

2.添加生成地址的接口

3.秒杀收到请求，先验证PathVariable

*  **数学公式验证码：**

**目的：****防机器人，分散请求**

思路：点击秒杀之前，先输入验证码，分散用户的请求

1.添加生成验证码接口

2.在获取秒杀路径的时候，验证验证码

*  **接口防刷限流：**

1.利用redis缓存：比如限制用户1min中内只允许访问多少次

2.可以利用拦截器减少对业务代码的入侵

*  **解决超卖问题：**

1.数据库加唯一索引：防止用户重复购买

2.更新库存sql增加库存数量判断：防止库存变成负数

(update table set count=count-1 where count>0)

*  **秒杀优化后的主体详细流程大致可以分为如下步骤：**

1.  程序启动后将秒杀库存写入redis，设置内存标记商品是否已秒杀完
2.  加入验证码
3.  秒杀前首先获取秒杀路径
4.  开始秒杀：

a.判断用户登录信息是否异常
    
     b.验证秒杀路径
    
     c.获取秒杀商品内存标记并判断是否已秒杀完
    
     d.redis获取用户订单，判断该用户是否是重复秒杀
    
     e.如果是正常秒杀，对于未秒杀完的商品进行redis减库存操作
    
     f.如果redis库存已<0，标记内存商品已秒杀完
    
     g.秒杀正常则加入队列，异步处理订单入库，返回排队中

5.前端轮询订单结果（是否秒杀成功）

*  **实现效果如下：**

**用户登录界面**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p3eDE5OTIxMjE1_size_16_color_FFFFFF_t_70][]

**描述商品列表页：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p3eDE5OTIxMjE1_size_16_color_FFFFFF_t_70 1][]

**秒杀商品详情页（增加验证码****）：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p3eDE5OTIxMjE1_size_16_color_FFFFFF_t_70 2][]

**增加访问限制（防刷限流）：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p3eDE5OTIxMjE1_size_16_color_FFFFFF_t_70 3][]

**重复秒杀处理：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p3eDE5OTIxMjE1_size_16_color_FFFFFF_t_70 4][]

**换一个秒杀商品重新秒杀：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p3eDE5OTIxMjE1_size_16_color_FFFFFF_t_70 5][]

**秒杀成功进入订单详情页：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p3eDE5OTIxMjE1_size_16_color_FFFFFF_t_70 6][]

**数据库查看库存正常减1**

![20191127102338603.png][]

**项目结构如下：**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3p3eDE5OTIxMjE1_size_16_color_FFFFFF_t_70 7][]

**秒杀接口部分核心代码如下：**

**获取验证码：**

@AccessLimit(seconds = 5, maxCount = 5, needLogin = true)
        @RequestMapping(value = "/path", method = RequestMethod.GET)
        @ResponseBody
        public Result<String> getMiaoshaPath(HttpServletRequest request, MiaoshaUser user,
                                             @RequestParam("goodsId") long goodsId,
                                             @RequestParam(value = "verifyCode", defaultValue = "0") int verifyCode
        ) {
            if (user == null) {
                return Result.error(CodeMsg.SESSION_ERROR);
            }
            boolean check = miaoshaService.checkVerifyCode(user, goodsId, verifyCode);
            if (!check) {
                return Result.error(CodeMsg.REQUEST_ILLEGAL);
            }
            String path = miaoshaService.createMiaoshaPath(user, goodsId);
            return Result.success(path);
        }

**获取秒杀路径： **

@RequestMapping(value = "/verifyCode", method = RequestMethod.GET)
        @ResponseBody
        public Result<String> getMiaoshaVerifyCod(HttpServletResponse response, MiaoshaUser user,
                                                  @RequestParam("goodsId") long goodsId) {
            if (user == null) {
                return Result.error(CodeMsg.SESSION_ERROR);
            }
            try {
                BufferedImage image = miaoshaService.createVerifyCode(user, goodsId);
                OutputStream out = response.getOutputStream();
                ImageIO.write(image, "JPEG", out);
                out.flush();
                out.close();
                return null;
            } catch (Exception e) {
                e.printStackTrace();
                return Result.error(CodeMsg.MIAOSHA_FAIL);
            }
        }

**执行秒杀：**

@RequestMapping(value = "/{path}/do_miaosha", method = RequestMethod.POST)
        @ResponseBody
        public Result<Integer> miaosha(Model model, MiaoshaUser user,
                                       @RequestParam("goodsId") long goodsId,
                                       @PathVariable("path") String path) {
            model.addAttribute("user", user);
            if (user == null) {
                return Result.error(CodeMsg.SESSION_ERROR);
            }
            //验证path
            boolean check = miaoshaService.checkPath(user, goodsId, path);
            if (!check) {
                return Result.error(CodeMsg.REQUEST_ILLEGAL);
            }
            //内存标记，减少redis访问
            if (localOverMap.size() > 0) {
                boolean over = localOverMap.get(goodsId);
                if (over) {
                    return Result.error(CodeMsg.MIAO_SHA_OVER);
                }
            }
    
            //判断是否已经秒杀到了
            MiaoshaOrder order = orderService.getMiaoshaOrderByUserIdGoodsId(user.getId(), goodsId);
            if (order != null) {
                return Result.error(CodeMsg.REPEATE_MIAOSHA);
            }
            //预减库存
            long stock = redisService.decr(GoodsKey.getMiaoshaGoodsStock, "" + goodsId);//10
            if (stock < 0) {
                localOverMap.put(goodsId, true);
                return Result.error(CodeMsg.MIAO_SHA_OVER);
            }
            //mq入队
            MiaoshaMessage mm = new MiaoshaMessage();
            mm.setUser(user);
            mm.setGoodsId(goodsId);
            sender.sendMiaoshaMessage(mm);
            return Result.success(0);//排队中

*  **采用JMeter做个简单的压力测试**

**JMeter简单使用参考：**[https://blog.csdn.net/zwx19921215/article/details/103261289][https_blog.csdn.net_zwx19921215_article_details_103261289]

操作系统：centos 虚拟机双核

测试参数：生成5000个用户(token信息)，设置5000个线程数循环10次，即运行50000次，然后查看聚合报告中的吞吐量。

![20191127103054573.png][]

**虚拟机测试结果吞吐量为2000左右，取决于机器配置**

注：该接口是在**未加入验证码**和**动态获取秒杀路径**的前提下测试的

项目完整代码下载地址：[http://zyshare.cn/resource/detail/22][http_zyshare.cn_resource_detail_22]

**源码免费下载地址：关注微信公众号“****虾米聊吧****”，回复关键字“****秒杀****”**

**关注微信公众号“****虾米聊吧****”，后续持续放送“****技术架构和资料****”干货！！！**

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[https_blog.csdn.net_zwx19921215_article_details_103255834]: https://blog.csdn.net/zwx19921215/article/details/103255834
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[20191127102338603.png]: https://img-blog.csdnimg.cn/20191127102338603.png
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[https_blog.csdn.net_zwx19921215_article_details_103261289]: https://blog.csdn.net/zwx19921215/article/details/103261289
[20191127103054573.png]: https://img-blog.csdnimg.cn/20191127103054573.png
[http_zyshare.cn_resource_detail_22]: http://zyshare.cn/resource/detail/22