springboot + rabbitmq + redis实现秒杀

实现说明

• 这里的核心在于如何在大并发的情况下保证数据库能扛得住压力，因为大并发的瓶颈在于数据库。如果用户的请求直接从前端传到数据库，显然，数据库是无法承受几十万上百万甚至上千万的并发量的。因此，我们能做的只能是减少对数据库的访问。例如，前端发出了100万个请求，通过我们的处理，最终只有10个会访问数据库，这样就会大大提升系统性能。再针对秒杀这种场景，因为秒杀商品的数量是有限的，因此采用上述实现方案。
• 假如，某个商品可秒杀的数量是10，那么在秒杀活动开始之前，把商品的ID和数量加载到Redis缓存。当服务端收到请求时，首先预减Redis中的数量，如果数量减到小于0时，那么随后的访问直接返回秒杀失败的信息。也就是说，最终只有10个请求会去访问数据库。
• 如果商品数量比较多，比如1万件商品参与秒杀，那么就有1万*10=10万个请求并发去访问数据库，数据库的压力还是会很大。这里就用到了另外一个非常重要的组件：消息队列。我们不是把请求直接去访问数据库，而是先把请求写到消息队列中，做一个缓存，然后再去慢慢的更新数据库。这样做之后，前端用户的请求可能不会立即得到响应是成功还是失败，很可能得到的是一个排队中的返回值，这个时候，需要客户端去服务端轮询，因为我们不能保证一定就秒杀成功了。当服务端出队，生成订单以后，把用户ID和商品ID写到缓存中，来应对客户端的轮询就可以了。这样处理以后，我们的应用是可以很简单的进行分布式横向扩展的，以应对更大的并发。当然，秒杀系统还有很多要处理的事情，比如限流防刷、分布式Session等等。

1、工具准备
rabbitmq安装：https://blog.csdn.net/m0_67392811/article/details/123827105
界面地址：http://localhost:15672/#/
用户名 guest
密码 guest

redis安装：https://blog.csdn.net/chen15369337607/article/details/119334531
jmeter安装：https://blog.csdn.net/yy1209357299/article/details/125480058
2、数据表

商品表

-- ------------------------------ Table structure for stock-- ----------------------------DROP TABLE IF EXISTS `stock`;CREATE TABLE `stock` (`id` int(11) unsigned NOT NULL AUTO_INCREMENT,`name` varchar(50) NOT NULL DEFAULT '' COMMENT '名称',`count` int(11) NOT NULL COMMENT '库存',`sale` int(11) NOT NULL COMMENT '已售',`version` int(11) NOT NULL COMMENT '乐观锁，版本号',PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;

订单表

-- ------------------------------ Table structure for stock_order-- ----------------------------DROP TABLE IF EXISTS `stock_order`;CREATE TABLE `stock_order` (`id` int(11) unsigned NOT NULL AUTO_INCREMENT,`sid` int(11) NOT NULL COMMENT '库存ID',`name` varchar(30) NOT NULL DEFAULT '' COMMENT '商品名称',`create_time` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP COMMENT '创建时间',PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8;

3、pom

<dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-amqp</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency>

4、代码结构

5、配置config
mq配置

package com.yy.msserver.config;import org.springframework.amqp.core.Binding;import org.springframework.amqp.core.BindingBuilder;import org.springframework.amqp.core.Exchange;import org.springframework.amqp.core.ExchangeBuilder;import org.springframework.amqp.core.Queue;import org.springframework.amqp.support.converter.Jackson2JsonMessageConverter;import org.springframework.amqp.support.converter.MessageConverter;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;/** * @author code * @Date 2022/6/27 14:03 * Description rabbitmq config * Version 1.0 */@Configurationpublic class MyRabbitMQConfig {//库存交换机public static final String STORY_EXCHANGE = "STORY_EXCHANGE";//订单交换机public static final String ORDER_EXCHANGE = "ORDER_EXCHANGE";//库存队列public static final String STORY_QUEUE = "STORY_QUEUE";//订单队列public static final String ORDER_QUEUE = "ORDER_QUEUE";//库存路由键public static final String STORY_ROUTING_KEY = "STORY_ROUTING_KEY";//订单路由键public static final String ORDER_ROUTING_KEY = "ORDER_ROUTING_KEY";@Beanpublic MessageConverter messageConverter() {return new Jackson2JsonMessageConverter();}//创建库存交换机@Beanpublic Exchange getStoryExchange() {return ExchangeBuilder.directExchange(STORY_EXCHANGE).durable(true).build();}//创建库存队列@Beanpublic Queue getStoryQueue() {return new Queue(STORY_QUEUE);}//库存交换机和库存队列绑定@Beanpublic Binding bindStory() {return BindingBuilder.bind(getStoryQueue()).to(getStoryExchange()).with(STORY_ROUTING_KEY).noargs();}//创建订单队列@Beanpublic Queue getOrderQueue() {return new Queue(ORDER_QUEUE);}//创建订单交换机@Beanpublic Exchange getOrderExchange() {return ExchangeBuilder.directExchange(ORDER_EXCHANGE).durable(true).build();}//订单队列与订单交换机进行绑定@Beanpublic Binding bindOrder() {return BindingBuilder.bind(getOrderQueue()).to(getOrderExchange()).with(ORDER_ROUTING_KEY).noargs();}}

redis配置

package com.yy.msserver.config;/** * @author code * @Date 2022/6/27 14:06 * Description redis config * Version 1.0 */import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;import org.springframework.data.redis.connection.RedisConnectionFactory;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;import org.springframework.data.redis.serializer.StringRedisSerializer;/** * @author code *@Date 2022/6/27 14:05 *Description redis config *Version 1.0 */@Configurationpublic class RedisConfig {// 配置redis得配置详解@Beanpublic RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory redisConnectionFactory) {RedisTemplate<String, Object> template = new RedisTemplate<String, Object>();template.setConnectionFactory(redisConnectionFactory);template.setKeySerializer(new StringRedisSerializer());template.setValueSerializer(new GenericJackson2JsonRedisSerializer());template.setHashKeySerializer(new GenericJackson2JsonRedisSerializer());template.setHashValueSerializer(new GenericJackson2JsonRedisSerializer());template.afterPropertiesSet();return template;}}

6、订单业务层
接口层

package com.yy.msserver.service;import com.yy.msserver.model.vo.Stock;/** * @author code * @Date 2022/6/24 9:25 * Description 订单接口 * Version 1.0 */public interface StockOrderService {public Integer createOrder(Integer id);public void decrByStock(Integer id);}

实现层

package com.yy.msserver.service.impl;import com.yy.msserver.dao.StockMapper;import com.yy.msserver.dao.StockOrderMapper;import com.yy.msserver.model.vo.Stock;import com.yy.msserver.model.vo.StockOrder;import com.yy.msserver.service.StockOrderService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import org.springframework.transaction.annotation.Transactional;import java.util.Date;/** * @author code * @Date 2022/6/24 9:25 * Description 订单实现 * Version 1.0 */@Servicepublic class StockOrderServiceImpl implements StockOrderService {@Autowiredprivate StockOrderMapper stockOrderMapper;@Autowiredprivate StockMapper stockMapper;@Override@Transactional(rollbackFor = Exception.class)public Integer createOrder(Integer id) {//校验库存Stock stock = checkStock(id);//if(stock.getCount()>0){//System.out.println("当前库存：" + stock.getCount());////扣库存//if(updateSale(stock) == 1){////}else {//return 0;//}//}//return 0;return createOrder(stock);}@Overridepublic void decrByStock(Integer id){//校验库存Stock stock = checkStock(id);if(stock.getCount()>0){System.out.println("当前库存：" + stock.getCount());//扣库存updateSale(stock);}}//校验库存private Stock checkStock(Integer id) {return stockMapper.checkStock(id);}//扣库存private int updateSale(Stock stock){return stockMapper.updateSale(stock);}//下订单private Integer createOrder(Stock stock){StockOrder order = new StockOrder();order.setSid(stock.getId());order.setCreateTime(new Date());order.setName(stock.getName());stockOrderMapper.createOrder(order);return order.getId();}}

7、redis实现层

package com.yy.msserver.service;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.data.redis.core.RedisTemplate;import org.springframework.stereotype.Service;import java.util.Date;import java.util.concurrent.TimeUnit;/** * @author code * @Date 2022/6/27 17:25 * Description redis * Version 1.0 */@Servicepublic class RedisService {@Autowiredprivate RedisTemplate<String, Object> redisTemplate;/** * 设置String键值对 * @param key * @param value * @param millis */public void put(String key, Object value, long millis) {redisTemplate.opsForValue().set(key, value, millis, TimeUnit.MINUTES);}public void putForHash(String objectKey, String hkey, String value) {redisTemplate.opsForHash().put(objectKey, hkey, value);}public <T> T get(String key, Class<T> type) {return (T) redisTemplate.boundValueOps(key).get();}public void remove(String key) {redisTemplate.delete(key);}public boolean expire(String key, long millis) {return redisTemplate.expire(key, millis, TimeUnit.MILLISECONDS);}public boolean persist(String key) {return redisTemplate.hasKey(key);}public String getString(String key) {return (String) redisTemplate.opsForValue().get(key);}public Integer getInteger(String key) {return (Integer) redisTemplate.opsForValue().get(key);}public Long getLong(String key) {return (Long) redisTemplate.opsForValue().get(key);}public Date getDate(String key) {return (Date) redisTemplate.opsForValue().get(key);}/** * 对指定key的键值减一 * @param key * @return */public Long decrBy(String key) {return redisTemplate.opsForValue().decrement(key);}}

8、mq实现层
减库存

package com.yy.msserver.service;import com.yy.msserver.config.MyRabbitMQConfig;import lombok.extern.slf4j.Slf4j;import org.springframework.amqp.rabbit.annotation.RabbitListener;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;/** * @author code * @Date 2022/6/27 15:22 * Description mq商品信息 * Version 1.0 */@Slf4j@Servicepublic class MQStockService {@Autowiredprivate StockOrderService stockService;/** * 监听库存消息队列，并消费 * @param id */@RabbitListener(queues = MyRabbitMQConfig.STORY_QUEUE)public void decrByStock(Integer id) {/** * 调用数据库service给数据库对应商品库存减一 */log.info("减库存");stockService.decrByStock(id);}}

下订单

package com.yy.msserver.service;import com.yy.msserver.config.MyRabbitMQConfig;import lombok.extern.slf4j.Slf4j;import org.springframework.amqp.rabbit.annotation.RabbitListener;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;/** * @author code * @Date 2022/6/27 15:19 * Description mq 订单队列 * Version 1.0 */@Service@Slf4jpublic class MQOrderService {@Autowiredprivate StockOrderService orderService;/** * 监听订单消息队列，并消费 * * @param id */@RabbitListener(queues = MyRabbitMQConfig.ORDER_QUEUE)public void createOrder(Integer id) {log.info("收到订单消息");orderService.createOrder(id);}}

9、redis模拟初始化库存量

package com.yy.msserver.config;import com.yy.msserver.service.RedisService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.ApplicationArguments;import org.springframework.stereotype.Component;import javax.annotation.PostConstruct;/** * @author code * @Date 2022/6/29 14:08 * Description 初始化 * Version 1.0 */@Componentpublic class InitConfig {@Autowiredprivate RedisService redisService;/** * redis初始化商品的库存量和信息 * @param * @throws Exception */@PostConstructpublic void init() {redisService.put("1", 10, 20);}}

10、controller控制层

 /** * 使用redis+消息队列进行秒杀实现 * * @param id 商品id * @return */@GetMapping( value = "/sec",produces = "application/json;charset=utf-8")@ResponseBodypublic String sec(@RequestParam(value = "id") int id) {String message = null;//调用redis给相应商品库存量减一Long decrByResult = redisService.decrBy(id+"");if (decrByResult >= 0) {/** * 说明该商品的库存量有剩余，可以进行下订单操作 *///发消息给库存消息队列，将库存数据减一rabbitTemplate.convertAndSend(MyRabbitMQConfig.STORY_EXCHANGE, MyRabbitMQConfig.STORY_ROUTING_KEY, id);//发消息给订单消息队列，创建订单rabbitTemplate.convertAndSend(MyRabbitMQConfig.ORDER_EXCHANGE, MyRabbitMQConfig.ORDER_ROUTING_KEY, id);message = "商品" + id + "秒杀成功";} else {/** * 说明该商品的库存量没有剩余，直接返回秒杀失败的消息给用户 */message ="商品" + id + "秒杀商品的库存量没有剩余,秒杀结束";}return message;}

11、测试
新建线程组——新建取样器（http请求）——新建查看结果树

12、测试结果