SpringBoot+Redis实现消息的发布与订阅的示例代码
1.什么是redis的发布与订阅
在官网的文档介绍中有一行介绍:Redis是一个快速稳定的发布/订阅消息系统。
2.Redis发布订阅
机制
Redis提供了发布与订阅的功能,可以用于消息的传输,Redis的发布订阅机制包括三部分,发布者、订阅者和Channel(主题或者队列)。
3.命令行实现功能
订阅主题
Redis采用SUBSCRIBE channel命令订阅某个主题,返回的参数subscribe表示已经成功订阅主题,第二个参数表示订阅的主题名称,第三个表示当前订阅数
127.0.0.1:6379> SUBSCRIBE ORDER-PAY-SUCCESS
Reading messages... (press Ctrl-C to quit)
1) "subscribe"
2) "ORDER-PAY-SUCCESS"
3) (integer) 1
模式匹配订阅
模式匹配功能是允许客户端订阅匹配某种模式的频道,Redis采用PSUBSCRIBE channel命令订阅匹配某种模式的所有频道,用*表示模式,*可以被任意值代替。
127.0.0.1:6379> PSUBSCRIBE ORDER-PAY-*
Reading messages... (press Ctrl-C to quit)
1) "psubscribe"
2) "ORDER-PAY-*"
3) (integer) 1
发布消息
Redis采用PUBLISH channel message命令在某个主题上发布消息,返回的参数是接收到消息的订阅者个数
127.0.0.1:6379> PUBLISH ORDER-PAY-SUCCESS DD202109071525
(integer) 1
取消订阅
Redis采用UNSUBSCRIBE channel或PUNSUBSCRIBE channel命令取消某个主题的订阅,由于Redis的订阅操作是阻塞式的,因此一旦客户端订阅了某个频道或模式,就将会一直处于订阅状态直到退出。在 SUBSCRIBE,PSUBSCRIBE,UNSUBSCRIBE 和 PUNSUBSCRIBE 命令中,其返回值都包含了该客户端当前订阅的频道和模式的数量,当这个数量变为0时,该客户端会自动退出订阅状态。
127.0.0.1:6379> UNSUBSCRIBE ORDER-PAY-SUCCESS
1) "unsubscribe"
2) "ORDER-PAY-SUCCESS"
3) (integer) 0
127.0.0.1:6379> PUNSUBSCRIBE ORDER-PAY-SUCCESS
1) "punsubscribe"
2) "ORDER-PAY-SUCCESS"
3) (integer) 0
测试
首先三个订阅者订阅ORDER-PAY-SUCCESS主题,当发送者在这个主题内发送订单号时,所有的订阅者都会收到这个主题的消息。
4.SpringBoot实现功能
Springboot整合Redis
引入依赖包
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<version>2.2.10.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>2.2.10.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
<version>2.4.1</version>
</dependency>
</dependencies>
配置yaml文件
server:
port: 8888
spring:
application:
name: spring-boot-redis
redis:
host: 127.0.0.1
port: 6379
配置消息监听
import com.demo.redis.listener.MessageListener;
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.StringRedisTemplate;
import org.springframework.data.redis.listener.PatternTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.data.redis.listener.adapter.MessageListenerAdapter;
@Configuration
public class RedisMessageConfig {
private static final String ORDER_PAY_SUCCESS = "ORDER-PAY-SUCCESS";
@Bean
public MessageListenerAdapter getMessageListenerAdapter(MessageListener messageListener){
return new MessageListenerAdapter(messageListener, "onMessage");
}
@Bean
public RedisMessageListenerContainer getRedisMessageListenerContainer(RedisConnectionFactory redisConnectionFactory, MessageListenerAdapter messageListenerAdapter){
RedisMessageListenerContainer redisMessageListenerContainer = new RedisMessageListenerContainer();
redisMessageListenerContainer.setConnectionFactory(redisConnectionFactory);
//订阅订单支付成功主题
redisMessageListenerContainer.addMessageListener(messageListenerAdapter, new PatternTopic(ORDER_PAY_SUCCESS));
return redisMessageListenerContainer;
}
@Bean
StringRedisTemplate template(RedisConnectionFactory connectionFactory) {
return new StringRedisTemplate(connectionFactory);
}
}
接收消息
import org.springframework.stereotype.Component;
@Component
public class MessageListener {
public void onMessage(String message){
System.out.println("接收消息:" + message);
}
}
测试
发送订单支付成功的消息
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.test.context.junit4.SpringRunner;
import javax.annotation.Resource;
@RunWith(value = SpringRunner.class)
@SpringBootTest
public class RedisPubTest {
private static final String ORDER_PAY_SUCCESS = "ORDER-PAY-SUCCESS";
@Resource
private StringRedisTemplate stringRedisTemplate;
@Test
public void sendMessage(){
for (int i = 0; i < 5; i++) {
stringRedisTemplate.convertAndSend(ORDER_PAY_SUCCESS,"DD" + System.currentTimeMillis());
}
}
}
接收到订单支付成功的消息
. ____ _ __ _ _
/\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
\\/ ___)| |_)| | | | | || (_| | ) ) ) )
' |____| .__|_| |_|_| |_\__, | / / / /
=========|_|==============|___/=/_/_/_/
:: Spring Boot :: (v2.2.10.RELEASE)2021-09-07 16:56:54.729 INFO 3712 --- [ main] com.demo.redis.RedisSubPubApplication : Starting RedisSubPubApplication on DESKTOP-595LI4G with PID 3712 (D:\Bai\Sources\spring-boot-demo\redis-sub-pub\target\classes started by 1 in D:\Bai\Sources\spring-boot-demo)
2021-09-07 16:56:54.735 INFO 3712 --- [ main] com.demo.redis.RedisSubPubApplication : No active profile set, falling back to default profiles: default
2021-09-07 16:56:55.205 INFO 3712 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Multiple Spring Data modules found, entering strict repository configuration mode!
2021-09-07 16:56:55.207 INFO 3712 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data Redis repositories in DEFAULT mode.
2021-09-07 16:56:55.229 INFO 3712 --- [ main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 11 ms. Found 0 Redis repository interfaces.
2021-09-07 16:56:55.557 INFO 3712 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8888 (http)
2021-09-07 16:56:55.565 INFO 3712 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2021-09-07 16:56:55.565 INFO 3712 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.38]
2021-09-07 16:56:55.669 INFO 3712 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2021-09-07 16:56:55.669 INFO 3712 --- [ main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 895 ms
2021-09-07 16:56:56.032 INFO 3712 --- [ main] o.s.s.concurrent.ThreadPoolTaskExecutor : Initializing ExecutorService 'applicationTaskExecutor'
2021-09-07 16:56:56.950 INFO 3712 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8888 (http) with context path ''
2021-09-07 16:56:56.952 INFO 3712 --- [ main] com.demo.redis.RedisSubPubApplication : Started RedisSubPubApplication in 2.557 seconds (JVM running for 3.436)
接收消息:DD1631005025949
接收消息:DD1631005025964
接收消息:DD1631005025965
接收消息:DD1631005025967
接收消息:DD1631005025968
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