文章前言
眾所周知,當遇到比較多數據不一致的問題時,大多數都是因為並發請求時,沒及時處理的原因,提一個電商平台比較經常出現得高並發場景限時秒殺活動,他們是怎么來防止超賣呢?如何實現高並發秒殺呢?。
本文模擬了高並發秒殺,並且防止了超賣,也模擬了純數據庫秒殺超賣得場景,本次模擬demo得框架技術為:SpringBoot+Mysql+Redis+RabbitMQ+tkmybatis
數據庫表結構:
一個為庫存表,一個為訂單表,本人使用得是mysql8.0。
完整得項目工具展示
Jmeter :
redisManager :
RabbitMQ :
編寫代碼
1.首先新建Springboot項目
2.可以先不勾選需要得jar包,項目初始化好之后,使用maven導入項目需要得jar包
pom.xml :
<dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> <exclusions> <exclusion> <groupId>org.junit.vintage</groupId> <artifactId>junit-vintage-engine</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <scope>runtime</scope> <optional>true</optional> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-lang3</artifactId> <version>3.8.1</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-amqp</artifactId> </dependency> <dependency> <groupId>io.jsonwebtoken</groupId> <artifactId>jjwt</artifactId> <version>0.7.0</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-redis</artifactId> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>2.1.0</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-tx</artifactId> </dependency> <dependency> <groupId>tk.mybatis</groupId> <artifactId>mapper-spring-boot-starter</artifactId> <version>2.0.3-beta1</version> </dependency> <dependency> <groupId>tk.mybatis</groupId> <artifactId>mapper</artifactId> <version>4.0.0</version> </dependency> </dependencies>
3.配置application.properties
spring.devtools.restart.enabled=false ##配置數據庫連接 spring.datasource.username=root spring.datasource.password=root server.port=8443 spring.datasource.url=jdbc:mysql://localhost:3306/ktoa?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC&allowMultiQueries=true spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver ##配置rabbitmq連接 spring.rabbitmq.host=localhost spring.rabbitmq.port=5672 spring.rabbitmq.username=guest spring.rabbitmq.password=guest ##配置連接redis --都記得打開服務 spring.redis.host=localhost spring.redis.port=6379 spring.redis.jedis.pool.max-active=1024 spring.redis.jedis.pool.max-wait=-1s spring.redis.jedis.pool.max-idle=200 spring.redis.password=123456
這時可以啟動一下springboot項目是否能夠正常啟動,如沒問題可以繼續往下編寫!!
4.新建pojo包,添加實體類
Order.java:
import lombok.Data; import javax.persistence.Column; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; import java.io.Serializable; @Data @Table(name = "t_order") public class Order implements Serializable { private static final long serialVersionUID = -8867272732777764701L; @Id @Column(name = "id") @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @Column(name = "order_name") private String order_name; @Column(name = "order_user") private String order_user; }
Stock.java:
import lombok.Data; import javax.persistence.Column; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; import java.io.Serializable; @Table(name = "stock") @Data public class Stock implements Serializable { private static final long serialVersionUID = 2451194410162873075L; @Id @Column(name = "id") @GeneratedValue(strategy = GenerationType.IDENTITY) private Long id; @Column(name = "name") private String name; @Column(name = "stock") private Long stock; }
因為本次數據庫操作方面使用了tkmybatis框架,所以實體類我們需要用到JPA的注解,來實現映射關系!!
5.配置tkmybatis得接口
新建名為base得包,在base下面新建service得接口
GenericMapper.interface:
import tk.mybatis.mapper.common.Mapper; import tk.mybatis.mapper.common.MySqlMapper; public interface GenericMapper<T> extends Mapper<T>, MySqlMapper<T> { }
關於這個接口得作用你需要了解太多,你只要知道我們得mapper層需要通過繼承它來實現數據庫操作,如果你接觸過jpa或者mybatis-plus,tkmybatis方式跟它們相似。
6.新建mapper層
新建名為mapper得包,在這個包下面新建
OrderMapper.interface:
import com.spbtrediskill.secondskill.base.service.GenericMapper; import com.spbtrediskill.secondskill.pojo.Order; import org.apache.ibatis.annotations.Mapper; @Mapper public interface OrderMapper extends GenericMapper<Order> { void insertOrder(Order order); }
StockMapper.interface:
import com.spbtrediskill.secondskill.base.service.GenericMapper; import com.spbtrediskill.secondskill.pojo.Stock; import org.apache.ibatis.annotations.Mapper; @Mapper public interface StockMapper extends GenericMapper<Stock> { }
7.編寫RabbitMQ和redis得配置類
新建config包,新建redis和RabbitMQ得類
MyRabbitMQConfig.java:
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.core.QueueBuilder; 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; import java.util.HashMap; import java.util.Map; @Configuration public class MyRabbitMQConfig { //庫存交換機 public static final String STORY_EXCHANGE = "STORY_EXCHANGE"; //訂單交換機 public static final String ORDER_EXCHANGE = "ORDER_EXCHANGE"; //庫存隊列 public static final String STORY_QUEUE = "STORY_QUEUE"; //訂單隊列 public static final String ORDER_QUEUE = "ORDER_QUEUE"; //庫存路由鍵 public static final String STORY_ROUTING_KEY = "STORY_ROUTING_KEY"; //訂單路由鍵 public static final String ORDER_ROUTING_KEY = "ORDER_ROUTING_KEY"; @Bean public MessageConverter messageConverter() { return new Jackson2JsonMessageConverter(); } //創建庫存交換機 @Bean public Exchange getStoryExchange() { return ExchangeBuilder.directExchange(STORY_EXCHANGE).durable(true).build(); } //創建庫存隊列 @Bean public Queue getStoryQueue() { return new Queue(STORY_QUEUE); } //庫存交換機和庫存隊列綁定 @Bean public Binding bindStory() { return BindingBuilder.bind(getStoryQueue()).to(getStoryExchange()).with(STORY_ROUTING_KEY).noargs(); } //創建訂單隊列 @Bean public Queue getOrderQueue() { return new Queue(ORDER_QUEUE); } //創建訂單交換機 @Bean public Exchange getOrderExchange() { return ExchangeBuilder.directExchange(ORDER_EXCHANGE).durable(true).build(); } //訂單隊列與訂單交換機進行綁定 @Bean public Binding bindOrder() { return BindingBuilder.bind(getOrderQueue()).to(getOrderExchange()).with(ORDER_ROUTING_KEY).noargs(); } }
RedisConfig .java:
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; @Configuration public class RedisConfig { // 配置redis得配置詳解 @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; } }
8.編寫service層
新建service包以及impl包,這里只提供實現類,接口可以自行編寫
OrderServiceImpl .java:
import com.spbtrediskill.secondskill.mapper.OrderMapper; import com.spbtrediskill.secondskill.pojo.Order; import com.spbtrediskill.secondskill.service.OrderService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; @Service public class OrderServiceImpl implements OrderService { @Autowired private OrderMapper orderMapper; @Override public void createOrder(Order order) { orderMapper.insert(order); } }
StockServiceImpl.java:
import com.spbtrediskill.secondskill.mapper.StockMapper; import com.spbtrediskill.secondskill.pojo.Stock; import com.spbtrediskill.secondskill.service.StockService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.util.CollectionUtils; import tk.mybatis.mapper.entity.Example; import java.util.List; @Service public class StockServiceImpl implements StockService { @Autowired private StockMapper stockMapper; // 秒殺商品后減少庫存 @Override public void decrByStock(String stockName) { Example example = new Example(Stock.class); Example.Criteria criteria = example.createCriteria(); criteria.andEqualTo("name", stockName); List<Stock> stocks = stockMapper.selectByExample(example); if (!CollectionUtils.isEmpty(stocks)) { Stock stock = stocks.get(0); stock.setStock(stock.getStock() - 1); stockMapper.updateByPrimaryKey(stock); } } // 秒殺商品前判斷是否有庫存 @Override public Integer selectByExample(String stockName) { Example example = new Example(Stock.class); Example.Criteria criteria = example.createCriteria(); criteria.andEqualTo("name", stockName); List<Stock> stocks = stockMapper.selectByExample(example); if (!CollectionUtils.isEmpty(stocks)) { return stocks.get(0).getStock().intValue(); } return 0; } }
9.配置rabbitmq得實現方式以及redis得實現方式
在 service包下面新建 MQOrderService.java
這個類屬於訂單得消費隊列
import com.spbtrediskill.secondskill.config.MyRabbitMQConfig; import com.spbtrediskill.secondskill.pojo.Order; import lombok.extern.slf4j.Slf4j; import org.springframework.amqp.rabbit.annotation.RabbitListener; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; @Service @Slf4j public class MQOrderService { @Autowired private OrderService orderService; /** * 監聽訂單消息隊列,並消費 * * @param order */ @RabbitListener(queues = MyRabbitMQConfig.ORDER_QUEUE) public void createOrder(Order order) { log.info("收到訂單消息,訂單用戶為:{},商品名稱為:{}", order.getOrder_user(), order.getOrder_name()); /** * 調用數據庫orderService創建訂單信息 */ orderService.createOrder(order); } }
MQStockService.java:
這個屬於庫存得消費隊列
import com.spbtrediskill.secondskill.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; @Service @Slf4j public class MQStockService { @Autowired private StockService stockService; /** * 監聽庫存消息隊列,並消費 * @param stockName */ @RabbitListener(queues = MyRabbitMQConfig.STORY_QUEUE) public void decrByStock(String stockName) { log.info("庫存消息隊列收到的消息商品信息是:{}", stockName); /** * 調用數據庫service給數據庫對應商品庫存減一 */ stockService.decrByStock(stockName); } }
RedisService.java:
這個配置類,主要用來實現對redis得key和value初始化以及對value得操作
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; @Service public class RedisService { @Autowired private RedisTemplate<String, Object> redisTemplate; /** * 設置String鍵值對 * @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); } /** * 對指定key的鍵值減一 * @param key * @return */ public Long decrBy(String key) { return redisTemplate.opsForValue().decrement(key); } }
下面為service包得完整目錄:
10.編寫controller層
在新建得controller包下面新建類 SecController.java
該controller提供了二個方法,一個為redis+rabbitmq實現高並發秒殺,第二個則用純數據庫模擬秒殺,出現超賣現象
import com.spbtrediskill.secondskill.config.MyRabbitMQConfig; import com.spbtrediskill.secondskill.pojo.Order; import com.spbtrediskill.secondskill.service.OrderService; import com.spbtrediskill.secondskill.service.RedisService; import com.spbtrediskill.secondskill.service.StockService; import lombok.extern.slf4j.Slf4j; import org.springframework.amqp.rabbit.core.RabbitTemplate; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.ResponseBody; @Controller @Slf4j public class SecController { @Autowired private RabbitTemplate rabbitTemplate; @Autowired private RedisService redisService; @Autowired private OrderService orderService; @Autowired private StockService stockService; /** * 使用redis+消息隊列進行秒殺實現 * * @param username * @param stockName * @return */ @PostMapping( value = "/sec",produces = "application/json;charset=utf-8") @ResponseBody public String sec(@RequestParam(value = "username") String username, @RequestParam(value = "stockName") String stockName) { log.info("參加秒殺的用戶是:{},秒殺的商品是:{}", username, stockName); String message = null; //調用redis給相應商品庫存量減一 Long decrByResult = redisService.decrBy(stockName); if (decrByResult >= 0) { /** * 說明該商品的庫存量有剩余,可以進行下訂單操作 */ log.info("用戶:{}秒殺該商品:{}庫存有余,可以進行下訂單操作", username, stockName); //發消息給庫存消息隊列,將庫存數據減一 rabbitTemplate.convertAndSend(MyRabbitMQConfig.STORY_EXCHANGE, MyRabbitMQConfig.STORY_ROUTING_KEY, stockName); //發消息給訂單消息隊列,創建訂單 Order order = new Order(); order.setOrder_name(stockName); order.setOrder_user(username); rabbitTemplate.convertAndSend(MyRabbitMQConfig.ORDER_EXCHANGE, MyRabbitMQConfig.ORDER_ROUTING_KEY, order); message = "用戶" + username + "秒殺" + stockName + "成功"; } else { /** * 說明該商品的庫存量沒有剩余,直接返回秒殺失敗的消息給用戶 */ log.info("用戶:{}秒殺時商品的庫存量沒有剩余,秒殺結束", username); message = "用戶:"+ username + "商品的庫存量沒有剩余,秒殺結束"; } return message; } }
純數據庫秒殺方式得方法:
/** * 實現純數據庫操作實現秒殺操作 * @param username * @param stockName * @return */ @RequestMapping("/secDataBase") @ResponseBody public String secDataBase(@RequestParam(value = "username") String username, @RequestParam(value = "stockName") String stockName) { log.info("參加秒殺的用戶是:{},秒殺的商品是:{}", username, stockName); String message = null; //查找該商品庫存 Integer stockCount = stockService.selectByExample(stockName); log.info("用戶:{}參加秒殺,當前商品庫存量是:{}", username, stockCount); if (stockCount > 0) { /** * 還有庫存,可以進行繼續秒殺,庫存減一,下訂單 */ //1、庫存減一 stockService.decrByStock(stockName); //2、下訂單 Order order = new Order(); order.setOrder_user(username); order.setOrder_name(stockName); orderService.createOrder(order); log.info("用戶:{}.參加秒殺結果是:成功", username); message = username + "參加秒殺結果是:成功"; } else { log.info("用戶:{}.參加秒殺結果是:秒殺已經結束", username); message = username + "參加秒殺活動結果是:秒殺已經結束"; } return message; }
11.編寫springboot啟動類
最后一步我們需要在springboot得啟動類中進行對redis得初始化,簡而言之就是調用我們上面寫得方法,新建一個redis緩存,模擬商品信息
import com.spbtrediskill.secondskill.service.RedisService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.ApplicationArguments; import org.springframework.boot.ApplicationRunner; import tk.mybatis.spring.annotation.MapperScan; @SpringBootApplication @MapperScan("com.spbtrediskill.secondskill.mapper") public class SecondskillApplication implements ApplicationRunner{ public static void main(String[] args) { SpringApplication.run(SecondskillApplication.class, args); } @Autowired private RedisService redisService; /** * redis初始化商品的庫存量和信息 * @param args * @throws Exception */ @Override public void run(ApplicationArguments args) throws Exception { redisService.put("watch", 10, 20); } }
項目得整個目錄:
至此我們得項目代碼就編寫完成了,記得仔細檢查是否有遺漏,下面准備進入最重要得測試環節!!
測試前提
上面代碼編寫完整之后我們可以啟動springboot,啟動之前記得打開redis和rabbitmq得服務,檢查是否出錯:
啟動成功之后打開Redis Desktop Manager工具,查看是否新建了一個redis :watch、
ok,如果好了,現在打開我們得JMeter工具,可能有些人對這個工具很陌生,下面我教大家如何使用JMeter,大佬忽略!!
首先選擇中文
完成中文之后,我們在測試計划右鍵,添加一個線程組
給這個線程組得數量為40,這個線程組得作用就是模擬40個用戶發送請求,去秒殺.
然后再在線程組右鍵,添加一個Http請求,這個就是我們用來發送請求得組件了
這個請求唯一要說得就是,隨機參數了,因為用戶名肯定不可能給40個相同得名字,這邊我們利用JMeter給用戶名得值為隨機數
點擊上方得白色小書本,選擇random,1-99得隨機數:
然后我們把這個函數字符串復制到http得參數上面去:
最后我們在測試計划建一個結果樹,查看我們發送請求返回得消息數據:
這些完成之后我們就可以開始發送請求了運行run
測試結果–redis+rabbitmq
運行之后查看我們得控制台:
可以看到日志已經打印到控制台了,用戶名為我們生成得隨機數。
再來看下數據庫訂單表order:
圖中有10條秒殺到商品得用戶信息和商品名,我再幫大家理一理,我們初始化得時候給watch庫存得數量為10,而我們使用JMeter模擬了40個人發請求,所以這10條數據,也就是40個用戶中搶到商品得10個人,也就是線程,誰搶到就是誰得。
再來查看下我們得結果樹:
結果樹上面有40條請求信息,通過其中我們可以看的每條請求得詳細數據以及返回得值。
現在我們再打開redismanager,其中我們初始化為10,現在是-30,可以知道有40個線程去獲取了它,現在為-30,每次前測試記得,手動清空緩存!!一定要記得
純數據庫方式秒殺結果
上面我們實現了redis+rabbitmq得秒殺,現在我們看看純數據庫方式得秒殺,看看有什么區別:
1.首先網stock庫存表新增一條數據,類似於redis得初始化
2.在jmeter中修改原來得http請求信息,其中小米對應數據庫得商品名
清空一下結果樹,我們開始運行
3.run
控制台:
重要得是查看數據庫得信息:
庫存已經清空,再看order表
這樣我們可以看到,明明只有10個庫存得商品,搶到得人卻不止10個,這樣明細超賣了,請求樹也可以看的超賣信息
總結
從這二個方式實現得秒殺就可以知道二者得區別,以及大概得了解這個過程是怎么實現得,寫這篇文章得主要初衷是方便那些剛接觸這方面得小白,沒有人剛來什么都會。