【Java秒杀方案】11.功能开发-【商品秒杀及优化】防止超卖 接口优化（redis预减库存，内存标记减少redis访问，RabbitMQ异步下单） 安全优化（隐藏秒杀接口，验证码，接口防刷）
2024-05-14 13:02:00
商品秒杀核心功能及优化
1. 正常秒杀流程
- 在商品详情页面等待秒杀倒计时–http://localhost:8080/goodsDetail.htm?goodsId=2
- 倒计时为0，开始秒杀，点【秒杀】按钮开始秒杀 --http://localhost:8080/seckill/doSeckill?goodsId=2
- 服务端收到秒杀请求，首先判断是不是在秒杀期间，再判断秒杀商品是否有库存
- 上面条件都满足，则进入下单流程，下单流程分3步，1.减库存 2.新增订单信息 3.新增秒杀订单信息
2. 秒杀存在问题
1.商品超卖 ，库存减为负数
- 商品超卖：10个商品库存，会出现超卖200多的订单
- 秒杀商品库存数会变成负数：因为进入下单流程后，扣减库存是直接减1，大量请求过来，就容易被减为负数
- 解决办法：1.通过下面的接口优化，减少过滤服务端的请求压力 2.优化sql,避免出现商品超卖，库存为负数的情况
- 如果用户秒杀成功，把秒杀订单信息放在redis里面（key-order:userId:goodsId），这样可以防止重复下单
2.商品库存全部秒杀之后，快速响应秒杀请求
- 通过在redis中设置 isStockEmpty:goodsId的值，有值，表示该商品已经全部秒杀结束，直接返回
- 通过内存标记：Map<Long,Boolean> EmptyStockMap，在SeckillController初始化时，把秒杀商品<goodsId,false>放在内存中，如果商品库存为空，设置EmptyStockMap<goodsId,true>，后面直接查这个HashMap的值，如果为true,直接返回，不需要再次访问redis
- 在SeckillController初始化时，把每个秒杀商品的库存放在redis的seckillGoods:goodsId中，以方便后面在redis预减库存
商品超卖，通过sql优化，同时放在同一用户反复抢购，设置唯一索引
OrderServiceImpl.seckill
boolean result = seckillGoodsService.update(new UpdateWrapper<SeckillGoods>().setSql("stock_count=stock_count-1").eq("id", seckillGoods.getId()).gt("stock_count", 0));if(!result){return null;}
唯一索引 t_seckill_order
3.功能要点（接口优化）
1.redis预减库存
SeckillController afterPropertiesSet（）
SeckillController初始化时，把每个秒杀商品的库存放在redis的seckillGoods:goodsId中
@Overridepublic void afterPropertiesSet() throws Exception {//初始化执行方法 商品库存数量加载到redisList<GoodsVo> list = goodsService.findGoodsVo();if(CollectionUtils.isEmpty(list)){return;}list.forEach(goodsVo ->{redisTemplate.opsForValue().set("seckillGoods:"+goodsVo.getId(),goodsVo.getStockCount());EmptyStockMap.put(goodsVo.getId(),false);});}
SeckillController.doSeckill() seckillGoods:goodsId
原来是先decrement,如果库存<=0,再increment,防止redis中库存为0 ，为了保证redsi事务一致，用lua脚本
Long stock = valueOperations.decrement("seckillGoods:" + goodsId);
log.info("stock:"+stock);
if(stock<=0){EmptyStockMap.put(goodsId,true);valueOperations.increment("seckillGoods:" + goodsId);return RespBean.error(RespBeanEnum.EMPTY_STOCK);
}
lua脚本可以防止redis中库存变成-1
//lua脚本可以防止redis中库存变成-1
Long stock=(Long)redisTemplate.execute(redisScript, Collections.singletonList("seckillGoods:" + goodsId),Collections.emptyList());
log.info("stock:"+stock);
if(stock<=0){EmptyStockMap.put(goodsId,true);//valueOperations.increment("seckillGoods:" + goodsId);return RespBean.error(RespBeanEnum.EMPTY_STOCK);
}
stock.lua
放在resources目录下面，与static 同级
if (redis.call('exists',KEYS[1]) == 1) thenlocal stock = tonumber(redis.call('get',KEYS[1]));if (stock > 0) thenredis.call('incrby',KEYS[1],-1);return stock;end;return 0;
end;2. 内存标记减少redis访问
初始化以及更新
见SeckillController afterPropertiesSet（）和 SeckillController.doSeckill() 关于EmptyStockMap.put操作
校验场景
SeckillController.doSeckill
//内存标记，减少读取redis的次数 当redis中库存为0，在内存中吧map对应goodsid的库存为空状态设置为trueif(EmptyStockMap.get(goodsId)){return RespBean.error(RespBeanEnum.EMPTY_STOCK);}
3. RabbitMQ异步下单
SeckillController.doSeckill 中校验库存，判断是否重复抢购，以及预减库存之后，发送消息，再通过MQ接受消息，异步下单
准备下单消息，发送
//下单SeckillMessage seckillMessage = new SeckillMessage(user, goodsId);mqSender.sendSeckillMessage(JSON.toJSONString(seckillMessage));//正在排队中 0return RespBean.success(0);
接受消息，校验判断后，下单
MQReceiver
@RabbitListener(queues = "seckillQueue")public void receive(String message){}
4.功能要点（安全优化）
1. 隐藏秒杀地址
通过准备每个商品，每个用户一个秒杀地址，方式代刷
seckillPath:userId:goodsId redis中的值，已经有效期
通过 /seckill/path 获取秒杀地址
SeckillController.path()
再通过 /seckill/"+path+"/doSeckill 这个真正的秒杀地址，秒杀
2. 验证码
通过验证码图片，校验每次提交操作是不是人手动操作，屏蔽机器人自动提交
<img src=""id="captchashow" alt="验证码">
<script>
$("#captchashow").click(function (){getCaptcha();})function getCaptcha(){console.log("getCaptcha...");$("#captchashow").attr("src","/seckill/captcha?goodsId="+goodsId+"&time="+(new Date()).getTime());}
</script>SeckillController.captcha()
3. 接口防刷
@AccessLimit(second=5,maxCount=5,needLogin=true)
通过设置接口AccessLimit注解，设置每5秒钟，最大请求次数为5次，需要有用户登录信息
通过redis计数器实现
String key=request.getRequestURI()+ user.getId();
通过设置5秒杀的有效期，累加当前5秒钟内的总的访问次数
/*** 获取秒杀地址* */@RequestMapping(value = "/path",method = RequestMethod.GET)@ResponseBody@AccessLimit(second=5,maxCount=5,needLogin=true)//通用接口限流public RespBean path(Model model, User user,Long goodsId,Long captcha,HttpServletRequest request) {}
AccessLimitInterceptor.preHandle()
Integer count = (Integer)valueOperations.get(key);if(null==count){//第一次 设置count值 设置超时时间 5秒valueOperations.set(key ,1,5, TimeUnit.SECONDS);}else if(count>5){log.info("AccessLimitInterceptor:"+"短时间之内请求次数太多");render(response,RespBeanEnum.REQUEST_LIMITED);return false;}else {valueOperations.increment(key);}
5.代码实现
SeckillController
@RequestMapping(value = “/path”,method = RequestMethod.GET)
path()
@RequestMapping(value = “/{path}/doSeckill”,method = RequestMethod.POST)
doSeckill()
@RequestMapping("/getResult")
getResult()
@RequestMapping("/captcha")
captcha()
package com.example.miaosha.controller;import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.example.miaosha.config.AccessLimit;
import com.example.miaosha.exception.GlobalException;
import com.example.miaosha.pojo.Order;
import com.example.miaosha.pojo.SeckillMessage;
import com.example.miaosha.pojo.SeckillOrder;
import com.example.miaosha.pojo.User;
import com.example.miaosha.rabbitmq.MQSender;
import com.example.miaosha.service.IGoodsService;
import com.example.miaosha.service.IOrderService;
import com.example.miaosha.service.ISeckillOrderService;
import com.example.miaosha.vo.GoodsVo;
import com.example.miaosha.vo.RespBean;
import com.example.miaosha.vo.RespBeanEnum;
import com.wf.captcha.ArithmeticCaptcha;
import com.wf.captcha.SpecCaptcha;
import com.wf.captcha.base.Captcha;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.data.redis.core.script.RedisScript;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.util.CollectionUtils;
import org.springframework.web.bind.annotation.*;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.awt.*;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;@Controller
@Slf4j
@RequestMapping("/seckill")
public class SeckillController implements InitializingBean {@Autowiredprivate IGoodsService goodsService;@Autowiredprivate ISeckillOrderService seckillOrderService;@Autowiredprivate IOrderService orderService;@Autowiredprivate RedisTemplate redisTemplate;@Autowiredprivate MQSender mqSender;@Autowiredprivate RedisScript<Long> redisScript;private Map<Long,Boolean> EmptyStockMap=new HashMap<>();/*** 获取秒杀地址* */@RequestMapping(value = "/path",method = RequestMethod.GET)@ResponseBody@AccessLimit(second=5,maxCount=5,needLogin=true)//通用接口限流public RespBean path(Model model, User user,Long goodsId,Long captcha,HttpServletRequest request) {log.info("captchaPage:"+captcha);if(null==user){return RespBean.error(RespBeanEnum.SESSION_ERROR);}ValueOperations valueOperations = redisTemplate.opsForValue();//现在访问次数 5秒内，访问5次 为了便于次数，验证码默认为0captcha=0L;/*String captchaRedisStr=(String) valueOperations.get("captcha:"+user.getId()+":"+goodsId);Long captchaRedis=Long.valueOf(captchaRedisStr);log.info("captchaRedis:"+captchaRedis);*/Long captchaRedis=0L;if(captchaRedis!=captcha){return RespBean.error(RespBeanEnum.CAPTCHA_ERROR);}String str=orderService.createPath(user,goodsId);return RespBean.success(str);}/*** 获取秒杀地址* */@RequestMapping(value = "/path0",method = RequestMethod.GET)@ResponseBody//通用接口限流public RespBean path0(Model model, User user,Long goodsId,Long captcha,HttpServletRequest request) {log.info("captchaPage:"+captcha);if(null==user){return RespBean.error(RespBeanEnum.SESSION_ERROR);}ValueOperations valueOperations = redisTemplate.opsForValue();String url=request.getRequestURI();log.info("url:"+url);//现在访问次数 5秒内，访问5次 为了便于次数，验证码默认为0captcha=0L;/*String captchaRedisStr=(String) valueOperations.get("captcha:"+user.getId()+":"+goodsId);Long captchaRedis=Long.valueOf(captchaRedisStr);log.info("captchaRedis:"+captchaRedis);*/Long captchaRedis=0L;if(captchaRedis!=captcha){return RespBean.error(RespBeanEnum.CAPTCHA_ERROR);}//Integer count = (Integer)valueOperations.get(url + ":" + user.getId());if(null==count){//第一次 设置count值 设置超时时间 5秒valueOperations.set(url + ":" + user.getId(),1,5,TimeUnit.SECONDS);}else if(count>5){return RespBean.error(RespBeanEnum.REQUEST_LIMITED);}else {valueOperations.increment(url + ":" + user.getId());}String str=orderService.createPath(user,goodsId);return RespBean.success(str);}//秒杀静态化，在商品详情页，直接ajax请求秒杀，成功后，跳转秒杀成功静态页面@RequestMapping(value = "/{path}/doSeckill",method = RequestMethod.POST)@ResponseBodypublic RespBean doSeckill(Model model, User user,Long goodsId,@PathVariable String path) {//判断秒杀库存 判断是否重复秒杀 秒杀（减库存 添加订单信息，添加秒杀订单信息）if(null==user){return RespBean.error(RespBeanEnum.SESSION_ERROR);}ValueOperations valueOperations = redisTemplate.opsForValue();Boolean check=orderService.checkPath(user,goodsId,path);if(!check){return RespBean.error(RespBeanEnum.REQUEST_ILLEGAL);}//判断库存是否>0//预减库存//内存标记，减少读取redis的次数 当redis中库存为0，在内存中吧map对应goodsid的库存为空状态设置为trueif(EmptyStockMap.get(goodsId)){return RespBean.error(RespBeanEnum.EMPTY_STOCK);}//Long stock = valueOperations.decrement("seckillGoods:" + goodsId);//redis lua脚本返回的库存 stokc是减之前的库存，如果库存是8,那返回的是8，实际上redis里面已经变成7，如果redis里面stock 是0,那直接返回0//lua脚本可以防止redis中库存变成-1Long stock=(Long)redisTemplate.execute(redisScript, Collections.singletonList("seckillGoods:" + goodsId),Collections.emptyList());log.info("stock:"+stock);if(stock<=0){EmptyStockMap.put(goodsId,true);//valueOperations.increment("seckillGoods:" + goodsId);return RespBean.error(RespBeanEnum.EMPTY_STOCK);}// 判断是否重复抢购SeckillOrder seckillOrder = (SeckillOrder)valueOperations.get("order:" + user.getId() + ":" + goodsId);if(null!=seckillOrder){return RespBean.error(RespBeanEnum.REPEATE_ERROR);}//下单SeckillMessage seckillMessage = new SeckillMessage(user, goodsId);mqSender.sendSeckillMessage(JSON.toJSONString(seckillMessage));//正在排队中 0return RespBean.success(0);/*GoodsVo goodsVo = goodsService.findGoodsVoById(goodsId);if(goodsVo.getStockCount()<1){model.addAttribute("errorMsg", RespBeanEnum.EMPTY_STOCK.getMessage());return RespBean.error(RespBeanEnum.EMPTY_STOCK);}SeckillOrder seckillOrder = (SeckillOrder)redisTemplate.opsForValue().get("order:" + user.getId() + ":" + goodsId);//SeckillOrder seckillOrder = seckillOrderService.getOne(new QueryWrapper<SeckillOrder>().eq("goods_id", goodsId).eq("user_id", user.getId()));if(null!=seckillOrder){model.addAttribute("errorMsg", RespBeanEnum.REPEATE_ERROR.getMessage());return RespBean.error(RespBeanEnum.REPEATE_ERROR);}Order order= orderService.seckill(goodsVo,user);return RespBean.success(order);*/}@RequestMapping("/getResult")@ResponseBodypublic RespBean getResult(Model model, User user, @RequestParam Long goodsId){if(null==user){return RespBean.error(RespBeanEnum.SESSION_ERROR);}//从秒杀订单表中搜索当前用户对应的goodsId有没有订单，有订单表示秒杀成功Long orderId=orderService.getResult(user,goodsId);return RespBean.success(orderId);}@RequestMapping("/captcha")public void captcha(HttpServletRequest request, HttpServletResponse response,User user,Long goodsId) throws Exception {if(user==null||goodsId<0){throw new GlobalException(RespBeanEnum.REQUEST_ILLEGAL);}// 设置请求头为输出图片类型response.setContentType("image/gif");response.setHeader("Pragma", "No-cache");response.setHeader("Cache-Control", "no-cache");response.setDateHeader("Expires", 0);// 算术类型ArithmeticCaptcha captcha = new ArithmeticCaptcha(130, 48,3);//captcha.setLen(3); // 几位数运算，默认是两位//captcha.getArithmeticString(); // 获取运算的公式：3+2=?//captcha.text(); // 获取运算的结果：5redisTemplate.opsForValue().set("captcha:"+user.getId()+":"+goodsId,captcha.text(),300, TimeUnit.SECONDS);log.info("captcha公式:"+captcha.getArithmeticString());log.info("captcha结果:"+captcha.text());captcha.out(response.getOutputStream()); // 输出验证码}//原始秒杀@RequestMapping("/doSeckill0")public String doSeckill0(Model model, User user,Long goodsId){//判断秒杀库存 判断是否重复秒杀 秒杀（减库存 添加订单信息，添加秒杀订单信息）GoodsVo goodsVo = goodsService.findGoodsVoById(goodsId);if(goodsVo.getStockCount()<1){model.addAttribute("errorMsg", RespBeanEnum.EMPTY_STOCK.getMessage());return "seckillFail";}SeckillOrder seckillOrder = seckillOrderService.getOne(new QueryWrapper<SeckillOrder>().eq("goods_id", goodsId).eq("user_id", user.getId()));if(null!=seckillOrder){model.addAttribute("errorMsg", RespBeanEnum.REPEATE_ERROR.getMessage());return "seckillFail";}Order order= orderService.seckill(goodsVo,user);model.addAttribute("order",order);return "orderDetail";}@Overridepublic void afterPropertiesSet() throws Exception {//初始化执行方法 商品库存数量加载到redisList<GoodsVo> list = goodsService.findGoodsVo();if(CollectionUtils.isEmpty(list)){return;}list.forEach(goodsVo ->{redisTemplate.opsForValue().set("seckillGoods:"+goodsVo.getId(),goodsVo.getStockCount());EmptyStockMap.put(goodsVo.getId(),false);});}
}IOrderService
seckill
getResult
createPath
checkPath
package com.example.miaosha.service;import com.example.miaosha.pojo.Order;
import com.baomidou.mybatisplus.extension.service.IService;
import com.example.miaosha.pojo.SeckillOrder;
import com.example.miaosha.pojo.User;
import com.example.miaosha.vo.GoodsVo;/*** <p>* 服务类* </p>** @author cch* @since 2021-11-17*/
public interface IOrderService extends IService<Order> {Order seckill(GoodsVo goodsVo, User user);Long getResult(User user, Long goodsId);String createPath(User user, Long goodsId);Boolean checkPath(User user, Long goodsId,String path);
}OrderServiceImpl
seckill
getResult
createPath
checkPath
package com.example.miaosha.service.impl;import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper;
import com.example.miaosha.mapper.SeckillOrderMapper;
import com.example.miaosha.pojo.Order;
import com.example.miaosha.mapper.OrderMapper;
import com.example.miaosha.pojo.SeckillGoods;
import com.example.miaosha.pojo.SeckillOrder;
import com.example.miaosha.pojo.User;
import com.example.miaosha.service.IOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.example.miaosha.service.ISeckillGoodsService;
import com.example.miaosha.service.ISeckillOrderService;
import com.example.miaosha.utils.MD5Util;
import com.example.miaosha.utils.UUIDUtil;
import com.example.miaosha.vo.GoodsVo;
import org.apache.commons.lang3.StringUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;import java.util.Date;
import java.util.concurrent.TimeUnit;/*** <p>* 服务实现类* </p>** @author cch* @since 2021-11-17*/
@Service
public class OrderServiceImpl extends ServiceImpl<OrderMapper, Order> implements IOrderService {@Autowiredprivate ISeckillGoodsService seckillGoodsService;@Autowiredprivate OrderMapper orderMapper;@Autowiredprivate SeckillOrderMapper seckillOrderMapper;@Autowiredprivate RedisTemplate redisTemplate;@Override@Transactionalpublic Order seckill(GoodsVo goodsVo, User user) {SeckillGoods seckillGoods = seckillGoodsService.getOne(new QueryWrapper<SeckillGoods>().eq("goods_id",goodsVo.getId()));seckillGoods.setStockCount(seckillGoods.getStockCount()-1);//seckillGoodsService.updateById(seckillGoods);//单独更新库存 设置条件 id= stock_count>0/*boolean result = seckillGoodsService.update(new UpdateWrapper<SeckillGoods>().set("stock_count", seckillGoods.getStockCount()).eq("id", seckillGoods.getId()).gt("stock_count", 0));if(!result){return null;}*/boolean result = seckillGoodsService.update(new UpdateWrapper<SeckillGoods>().setSql("stock_count=stock_count-1").eq("id", seckillGoods.getId()).gt("stock_count", 0));if(!result){return null;}Order order = new Order();order.setUserId(user.getId());order.setGoodsId(goodsVo.getId());order.setDeliveryAddrId(1L);order.setGoodsName(goodsVo.getGoodsName());order.setGoodsCount(1);order.setGoodsPrice(goodsVo.getSeckillPrice());order.setOrderChannel(1);order.setStatus(0);order.setCreateDate(new Date());orderMapper.insert(order);SeckillOrder seckillOrder = new SeckillOrder();seckillOrder.setUserId(user.getId());seckillOrder.setOrderId(order.getId());seckillOrder.setGoodsId(goodsVo.getId());seckillOrderMapper.insert(seckillOrder);//秒杀成功，表秒杀订单存入redis uid+gidredisTemplate.opsForValue().set("order:"+user.getId()+":"+goodsVo.getId(),seckillOrder);return order;}/** return orderId 成功 id /秒杀失败-1 /排队中 0* */@Overridepublic Long getResult(User user, Long goodsId) {//改为从redis中获取秒杀成功信息SeckillOrder seckillOrder =(SeckillOrder)redisTemplate.opsForValue().get("order:"+user.getId()+":"+goodsId);/*SeckillOrder seckillOrder = seckillOrderMapper.selectOne(new QueryWrapper<SeckillOrder>().eq("goods_id", goodsId).eq("user_id", user.getId()));*/if(null !=seckillOrder){return seckillOrder.getOrderId();}//如果没有redis中没有查到订单消息，看是否秒杀结束，如果已经秒杀结束，由于本次秒杀结束，所以判断没有秒杀到//特殊情况：如果秒杀100,只有10人参与，那肯定都会秒杀到，所以不存在活动没有结束，一直查询秒杀结果的情况if(redisTemplate.hasKey("isStockEmpty:"+goodsId)){//秒杀结束return -1L;}return 0L;}@Overridepublic String createPath(User user, Long goodsId) {//获取秒杀地址String str = MD5Util.md5(UUIDUtil.uuid() + "123456");ValueOperations valueOperations = redisTemplate.opsForValue();valueOperations.set("seckillPath:"+user.getId()+":"+goodsId,str,60, TimeUnit.SECONDS);return str;}@Overridepublic Boolean checkPath(User user, Long goodsId,String path) {ValueOperations valueOperations = redisTemplate.opsForValue();String redisPath = (String)valueOperations.get("seckillPath:" + user.getId() + ":" + goodsId);if(user==null||goodsId<0||StringUtils.isEmpty(redisPath)){return false;}if(redisPath.equals(path)){return true;}return false;}
}RedisConfig
redisTemplate
redisScript
package com.example.miaosha.config;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.RedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;@Configuration
public class RedisConfig {@Beanpublic RedisTemplate<String,Object> redisTemplate(RedisConnectionFactory redisConnectionFactory){RedisTemplate<String,Object> redisTemplate= new RedisTemplate<>();redisTemplate.setKeySerializer(new StringRedisSerializer());redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());redisTemplate.setHashKeySerializer(new StringRedisSerializer());redisTemplate.setHashValueSerializer(new GenericJackson2JsonRedisSerializer());redisTemplate.setConnectionFactory(redisConnectionFactory);return redisTemplate;}@Beanpublic DefaultRedisScript<Long> script(){DefaultRedisScript<Long> redisScript =new DefaultRedisScript<>();//lock.lua脚本位置和application.yml 同级目录redisScript.setLocation(new ClassPathResource("stock.lua"));redisScript.setResultType(Long.class);return redisScript;}}SeckillMessage
异步下单，发送消息体
package com.example.miaosha.pojo;import com.example.miaosha.vo.GoodsVo;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;@Data
@NoArgsConstructor
@AllArgsConstructor
public class SeckillMessage {private User user;private Long goodsId;
}MQSender
异步下单，发送消息
package com.example.miaosha.rabbitmq;import lombok.extern.slf4j.Slf4j;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessageProperties;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;@Service
@Slf4j
public class MQSender {@Autowiredprivate RabbitTemplate rabbitTemplate;public void sendSeckillMessage(String message){log.info("sendSeckill发送消息:"+message);rabbitTemplate.convertAndSend("seckillExchange","seckill.message",message);}/*public void send(Object msg){log.info("发送消息:"+msg);rabbitTemplate.convertAndSend("q1",msg);}public void sendFanout(Object msg){log.info("fanout发送消息:"+msg);rabbitTemplate.convertAndSend("fanoutExchange","",msg);}public void sendDirect01(Object msg){log.info("directExchange发送消息:"+msg);rabbitTemplate.convertAndSend("direct_Exchange","queue.red",msg);}public void sendDirect02(Object msg){log.info("directExchange发送消息:"+msg);rabbitTemplate.convertAndSend("direct_Exchange","queue.green",msg);}public void sendTopic01(Object msg){log.info("topic_Exchange发送消息:"+msg);rabbitTemplate.convertAndSend("topic_Exchange","aaa.queue.bbb",msg);}public void sendTopic02(Object msg){log.info("topic_Exchange发送消息:"+msg);rabbitTemplate.convertAndSend("topic_Exchange","queue.red.message",msg);}public void sendHead01(String msg){log.info("topic_Exchange发送消息:"+msg);MessageProperties properties=new MessageProperties();properties.setHeader("color","red");properties.setHeader("speed","low");Message message=new Message(msg.getBytes(),properties);rabbitTemplate.convertAndSend("head_Exchange","",message);}public void sendHead02(String msg){log.info("topic_Exchange发送消息:"+msg);MessageProperties properties=new MessageProperties();properties.setHeader("color","red");properties.setHeader("speed","fast");Message message=new Message(msg.getBytes(),properties);rabbitTemplate.convertAndSend("head_Exchange","",message);}*/}MQReceiver
异步下单，接受消息，进入下单流程
@RabbitListener(queues = “seckillQueue”)
public void receive(String message){}
package com.example.miaosha.rabbitmq;import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.example.miaosha.pojo.SeckillMessage;
import com.example.miaosha.pojo.SeckillOrder;
import com.example.miaosha.pojo.User;
import com.example.miaosha.service.IGoodsService;
import com.example.miaosha.service.IOrderService;
import com.example.miaosha.service.ISeckillOrderService;
import com.example.miaosha.utils.JsonUtil;
import com.example.miaosha.vo.GoodsVo;
import com.example.miaosha.vo.RespBean;
import com.example.miaosha.vo.RespBeanEnum;
import lombok.extern.slf4j.Slf4j;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Service;
import org.springframework.web.bind.annotation.RequestMapping;@Service
@Slf4j
public class MQReceiver {@Autowiredprivate IGoodsService goodsService;@Autowiredprivate RedisTemplate redisTemplate;@Autowiredprivate ISeckillOrderService seckillOrderService;@Autowiredprivate IOrderService orderService;@RabbitListener(queues = "seckillQueue")public void receive(String message){log.info("seckillQueue接受消息:"+message);SeckillMessage seckillMessage = JSON.parseObject(message, SeckillMessage.class);Long goodsId = seckillMessage.getGoodsId();User user = seckillMessage.getUser();//下单操作GoodsVo goodsVo = goodsService.findGoodsVoById(goodsId);if(goodsVo.getStockCount()<1){//如果有key,表示，没有库存，结束redisTemplate.opsForValue().set("isStockEmpty:"+goodsId,"0");return;}//1. 判断是否重复抢购 从redis中判断ValueOperations valueOperations = redisTemplate.opsForValue();SeckillOrder seckillOrder = (SeckillOrder)valueOperations.get("order:" + user.getId() + ":" + goodsId);if(null!=seckillOrder){return;}//重复抢购//2.从t_seckill_order中获取SeckillOrder seckillOrderDB = seckillOrderService.getOne(new QueryWrapper<SeckillOrder>().eq("user_id", user.getId()).eq("goods_id", goodsId));if(null!=seckillOrderDB){return;}//重复抢购orderService.seckill(goodsVo,user);}/*@RabbitListener(queues = "q1")public void receive(Object msg){log.info("接受消息:"+msg);}@RabbitListener(queues = "queue_fanout01")public void receive1(Object msg){log.info("queue_fanout01接受消息:"+msg);}@RabbitListener(queues = "queue_fanout02")public void receive2(Object msg){log.info("queue_fanout02接受消息:"+msg);}@RabbitListener(queues = "direct_queue01")public void receive3(Object msg){log.info("direct_queue01接受消息:"+msg);}@RabbitListener(queues = "direct_queue02")public void receive4(Object msg){log.info("direct_queue02接受消息:"+msg);}@RabbitListener(queues = "topic_queue01")public void receive5(Message msg){log.info("topic_queue01接受消息:"+msg);}@RabbitListener(queues = "topic_queue02")public void receive6(Message msg){log.info("topic_queue02接受消息:"+msg);}@RabbitListener(queues = "head_queue01")public void receive7(Message msg){log.info("head_queue01接受消息:"+new String(msg.getBody()));}@RabbitListener(queues = "head_queue02")public void receive8(Message msg){log.info("head_queue02接受消息:"+new String(msg.getBody()));}*/}RabbitMQConfig
初始化 队列，交换机 路由键，已经绑定
QUEUE
EXCHANGE
ROUTINGKEY
package com.example.miaosha.config;import org.springframework.amqp.core.*;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;import java.util.HashMap;
import java.util.Map;@Configuration
public class RabbitMQConfig {private static final String QUEUE="seckillQueue";private static final String EXCHANGE="seckillExchange";private static final String ROUTINGKEY="seckill.#";@Beanpublic Queue seckillQueue(){return new Queue(QUEUE);}@Beanpublic TopicExchange seckillExchange(){return new TopicExchange(EXCHANGE);}@Beanpublic Binding binding(){return BindingBuilder.bind(seckillQueue()).to(seckillExchange()).with(ROUTINGKEY);}}【Java秒杀方案】11.功能开发-【商品秒杀及优化】防止超卖 接口优化（redis预减库存，内存标记减少redis访问，RabbitMQ异步下单） 安全优化（隐藏秒杀接口，验证码，接口防刷）相关推荐
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