优惠券秒杀项目

一、添加优惠券的同时，将优惠券信息，以及用户列表放到redis中

@Override
@Transactional
public void addSeckillVoucher(Voucher voucher) {// 保存优惠券save(voucher);// 保存秒杀信息SeckillVoucher seckillVoucher = new SeckillVoucher();seckillVoucher.setVoucherId(voucher.getId());seckillVoucher.setStock(voucher.getStock());seckillVoucher.setBeginTime(voucher.getBeginTime());seckillVoucher.setEndTime(voucher.getEndTime());seckillVoucherService.save(seckillVoucher);// 保存秒杀内容放到 Redis 中，包括库存、开始时间和结束时间，使用 hashMap<String, String> voucherData = new HashMap<>();voucherData.put("stock", String.valueOf(voucher.getStock()));voucherData.put("beginTime", String.valueOf(voucher.getBeginTime().toInstant(ZoneOffset.UTC).toEpochMilli()));voucherData.put("endTime", String.valueOf(voucher.getEndTime().toInstant(ZoneOffset.UTC).toEpochMilli()));stringRedisTemplate.opsForHash().putAll("seckill:voucher:" + voucher.getId(), voucherData);// 加一个 set 集合，用来放抢到优惠券的用户 ID，防止重复抢stringRedisTemplate.opsForSet().add("seckill:voucher:users:" + voucher.getId(), "0");
}

使用Redis生成订单ID：

@Component
public class RedisIdWorker {/*** 开始时间戳*/private static final long BEGIN_TIMESTAMP = 1640995200L;/*** 序列号的位数*/private static final int COUNT_BITS = 32;private StringRedisTemplate stringRedisTemplate;public RedisIdWorker(StringRedisTemplate stringRedisTemplate) {this.stringRedisTemplate = stringRedisTemplate;}public long nextId(String keyPrefix) {// 1.生成时间戳LocalDateTime now = LocalDateTime.now();long nowSecond = now.toEpochSecond(ZoneOffset.UTC);long timestamp = nowSecond - BEGIN_TIMESTAMP;// 2.生成序列号// 2.1.获取当前日期，精确到天String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));// 2.2.自增长//如果不存在，会自动创建然后开始自增long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);// 3.拼接并返回return timestamp << COUNT_BITS | count;}
}

二、使用lua查看是否满足购买条件

2.1 编写lua脚本

-- KEYS 和 ARGV 是 Redis 提供的两种参数类型-- KEYS[1] 是秒杀活动的哈希表键，包含库存、开始时间和结束时间
-- KEYS[2] 是记录用户ID的集合，防止重复购买-- ARGV[1] 是用户ID，用于检查该用户是否已经购买过
-- ARGV[2] 是当前时间的时间戳（秒），用于与秒杀活动的开始和结束时间进行比较-- 获取秒杀活动的信息
local stock = redis.call('hget', KEYS[1], 'stock')
local beginTime = redis.call('hget', KEYS[1], 'beginTime')
local endTime = redis.call('hget', KEYS[1], 'endTime')-- 当前时间
local currentTime = tonumber(ARGV[2])-- 检查活动是否在有效时间内
beginTime = tonumber(beginTime)
endTime = tonumber(endTime)if currentTime < beginTime thenreturn -4  -- 活动尚未开始
endif currentTime > endTime thenreturn -5  -- 活动已经结束
end-- 检查库存是否足够
stock = tonumber(stock)if stock <= 0 thenreturn -2  -- 库存不足
end-- 获取用户ID
local userId = ARGV[1]-- 检查用户是否已经购买过
local userExists = redis.call('sismember', KEYS[2], userId)
if userExists == 1 thenreturn -3  -- 用户已经购买过
end-- 扣减库存
redis.call('hincrby', KEYS[1], 'stock', -1)-- 记录用户购买信息
redis.call('sadd', KEYS[2], userId)-- 成功，返回 1
return 1

package com.hmdp.service.impl;import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.util.Arrays;
import java.util.List;/*** <p>*  服务实现类* </p>** @author 虎哥* @since 2021-12-22*/
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {@AutowiredISeckillVoucherService seckillVoucherService;@AutowiredRedisIdWorker redisIdWorker;@AutowiredStringRedisTemplate stringRedisTemplate;@Autowiredprivate RabbitTemplate rabbitTemplate;// 秒杀 Lua 脚本, 当类加载的时候就执行private static final DefaultRedisScript<Long> SECKILL_SCRIPT;static {SECKILL_SCRIPT = new DefaultRedisScript<>();SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));SECKILL_SCRIPT.setResultType(Long.class);}@Overridepublic Result seckillVoucher(Long voucherId) {// 1. 使用 Redis 的 Lua 脚本，查看是否满足购买条件，包括时间、库存、用户是否已经购买String voucherKey = "seckill:voucher:" + voucherId;String userKey = "seckill:voucher:users:" + voucherId;long currentTimeMillis = LocalDateTime.now().toInstant(ZoneOffset.UTC).toEpochMilli();long userId = 1L; // 从用户会话中获取// 2. 调用 Lua 脚本Long result = stringRedisTemplate.execute(SECKILL_SCRIPT, // Lua 脚本Arrays.asList(voucherKey, userKey), // Key 列表String.valueOf(userId), // 参数列表：用户 ID 转为字符串String.valueOf(currentTimeMillis) // 参数列表：当前时间转为字符串);// 3. 处理 Lua 脚本返回的结果if (result != null) {int r = result.intValue();switch (r) {case -2:return Result.fail("库存不足！");case -3:return Result.fail("您已购买过该优惠券！");case -4:return Result.fail("秒杀活动尚未开始！");case -5:return Result.fail("秒杀活动已经结束！");case 1:// 成功抢购，将订单信息发送到 RabbitMQ 队列中VoucherOrder voucherOrder = createOrder(voucherId, userId);rabbitTemplate.convertAndSend("seckill.direct", "order.routing.key", voucherOrder);return Result.ok("抢购成功，订单正在处理中！");default:return Result.fail("未知错误！");}}return Result.fail("操作失败！");}// 创建订单private VoucherOrder createOrder(Long voucherId, Long userId) {VoucherOrder order = new VoucherOrder();order.setVoucherId(voucherId);order.setUserId(userId);order.setId(redisIdWorker.nextId("order")); // 生成订单 IDreturn order;}
}

package com.hmdp.consumer;import com.hmdp.entity.VoucherOrder;
import com.hmdp.service.IVoucherOrderService;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.amqp.core.*;
import org.springframework.amqp.rabbit.annotation.QueueBinding;import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.amqp.rabbit.annotation.Exchange;
import org.springframework.amqp.rabbit.annotation.Queue;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;import java.util.concurrent.TimeUnit;@Component
@Slf4j
public class OrderConsumer {@Autowiredprivate RedissonClient redissonClient;@Autowiredprivate IVoucherOrderService voucherOrderService;@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "seckill.order.queue"),exchange = @Exchange(name = "seckill.direct", type = ExchangeTypes.DIRECT),key = "order.routing.key"))public void processOrder(VoucherOrder order) {String lockKey = "order:lock:" + order.getId();RLock lock = redissonClient.getLock(lockKey);try {boolean isLockAcquired = lock.tryLock(10, 5, TimeUnit.SECONDS);if (isLockAcquired) {try {voucherOrderService.save(order);} finally {lock.unlock();}} else {// 无法获取锁，可能日志记录}} catch (InterruptedException e) {Thread.currentThread().interrupt();// 错误处理} catch (Exception e) {// 错误处理}}}

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.3.12.RELEASE</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.hmdp</groupId><artifactId>hm-dianping</artifactId><version>0.0.1-SNAPSHOT</version><name>hm-dianping</name><description>Demo project for Spring Boot</description><properties><java.version>1.8</java.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency><dependency><groupId>org.apache.commons</groupId><artifactId>commons-pool2</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><scope>runtime</scope><version>5.1.47</version></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.4.3</version></dependency><!--hutool--><dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId><version>5.7.17</version></dependency><!--rabbitmq--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-amqp</artifactId></dependency><!--redission--><dependency><groupId>org.redisson</groupId><artifactId>redisson</artifactId><version>3.13.6</version></dependency><!--fastjson--><dependency><groupId>com.fasterxml.jackson.dataformat</groupId><artifactId>jackson-dataformat-xml</artifactId><version>2.9.10</version></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId><configuration><excludes><exclude><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></exclude></excludes></configuration></plugin></plugins></build></project>

server:port: 8081
spring:application:name: hmdpdatasource:driver-class-name: com.mysql.jdbc.Driverurl: jdbc:mysql://127.0.0.1:3306/hmdp?useSSL=false&serverTimezone=UTCusername: rootpassword: rootredis:host: 192.168.0.103port: 6379password: 123lettuce:pool:max-active: 10max-idle: 10min-idle: 1time-between-eviction-runs: 10srabbitmq:host: 192.168.0.103 # 你的虚拟机IPport: 5672 # 端口virtual-host: /seckill # 虚拟主机username: seckill # 用户名password: 123123 # 密码jackson:default-property-inclusion: non_null # JSON处理时忽略非空字段
mybatis-plus:type-aliases-package: com.hmdp.entity # 别名扫描包configuration:map-underscore-to-camel-case: true
logging:level:com.hmdp: debugorg.springframework.amqp: DEBUG