位置：首页>> 软件编程>> java编程>> springboot +rabbitmq+redis实现秒杀示例

springboot +rabbitmq+redis实现秒杀示例

作者：yy1209357299　　发布时间：2022-04-21 02:29:28　

标签：springboot,rabbitmq,redis,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://www.jb51.net/article/253706.htm

界面地址：http://localhost:15672/#/
用户名 guest
密码 guest

redis安装：https://www.jb51.net/article/145704.htm
jmeter安装：https://www.jb51.net/article/232152.htm

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
*/
@Configuration
public 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";
@Bean
public MessageConverter messageConverter() {
return new Jackson2JsonMessageConverter();
}
//创建库存交换机
@Bean
public Exchange getStoryExchange() {
return ExchangeBuilder.directExchange(STORY_EXCHANGE).durable(true).build();
}
//创建库存队列
@Bean
public Queue getStoryQueue() {
return new Queue(STORY_QUEUE);
}
//库存交换机和库存队列绑定
@Bean
public Binding bindStory() {
return BindingBuilder.bind(getStoryQueue()).to(getStoryExchange()).with(STORY_ROUTING_KEY).noargs();
}
//创建订单队列
@Bean
public Queue getOrderQueue() {
return new Queue(ORDER_QUEUE);
}
//创建订单交换机
@Bean
public Exchange getOrderExchange() {
return ExchangeBuilder.directExchange(ORDER_EXCHANGE).durable(true).build();
}
//订单队列与订单交换机进行绑定
@Bean
public 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
*/
@Configuration
public class RedisConfig {
// 配置redis得配置详解
@Bean
public 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
*/
@Service
public class StockOrderServiceImpl implements StockOrderService {
@Autowired
private StockOrderMapper stockOrderMapper;

@Autowired
private 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);
}

@Override
public 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
*/
@Service
public class RedisService {
@Autowired
private 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
@Service
public class MQStockService {
@Autowired
private 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
@Slf4j
public class MQOrderService {
@Autowired
private 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
*/
@Component
public class InitConfig {
@Autowired
private RedisService redisService;
/**
* redis初始化商品的库存量和信息
* @param
* @throws Exception
*/
@PostConstruct
public 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")
@ResponseBody
public 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;
}