springboot整合redis实现消息发布和订阅
https://blog.csdn.net/weixin_43587472/article/details/112296403
springboot整合redis实现消息发布和订阅
先了解一下redis消息发布订阅的机制:
发布者将消息发布在一个channel(可认为是频道)上,可以供多个订阅者订阅查看信息,所以说channel是连接发布者和订阅者之间的桥梁。
1.实现一个用于接听消息的实体类
@Component
public class MessageReceiver implements MessageListener {
@Autowired
private RedisTemplate redisTemplate;
private static Logger logger = LoggerFactory.getLogger(MessageReceiver.class);
@Override
public void onMessage(Message message, byte[] bytes) {
RedisSerializer<String> redisSerializer = redisTemplate.getStringSerializer();
String msg= redisSerializer.deserialize(message.getBody());
System.out.println("接收到的消息是:"+ msg);
logger.info("Received <" + msg + ">");
}
}
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此处可用@Component注解标识 ,也可以在配置文件即@Configration注解文件中用@Bean注入(这个是标准的springboot注入方式)
2.进行redis消息监听器和适配器的配置
package com.remoteTest.cache.config;
import com.remoteTest.cache.bean.Employee;
import com.remoteTest.cache.bean.MessageReceiver;
import org.springframework.boot.autoconfigure.AutoConfigureAfter;
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.listener.PatternTopic;
import org.springframework.data.redis.listener.RedisMessageListenerContainer;
import org.springframework.data.redis.listener.adapter.MessageListenerAdapter;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import java.net.UnknownHostException;
@Configuration
@AutoConfigureAfter({MessageReceiver.class})
public class MyRedisConfig {
/*
* Redis消息监听器容器
* 这个容器加载了RedisConnectionFactory和消息监听器
* 可以添加多个监听不同话题的redis监听器,只需要把消息监听器和相应的消息订阅处理器绑定,该消息监听器
* 通过反射技术调用消息订阅处理器的相关方法进行一些业务处理
*/
@Bean
public RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory, MessageListenerAdapter adapter) {
RedisMessageListenerContainer container = new RedisMessageListenerContainer();
container.setConnectionFactory(connectionFactory);
//可以添加多个 messageListener
container.addMessageListener(adapter,new PatternTopic("topic"));
return container;
}
/*
* 消息监听器适配器,绑定消息处理器,利用反射技术调用消息处理器的业务方法
* 将MessageReceiver注册为一个消息监听器,可以自定义消息接收的方法(handleMessage)
* 如果不指定消息接收的方法,消息监听器会默认的寻找MessageReceiver中的onMessage这个方法作为消息接收的方法
*/
@Bean
public MessageListenerAdapter adapter(MessageReceiver messageReceiver) {
return new MessageListenerAdapter(messageReceiver, "onMessage");
}
}
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container.addMessageListener(adapter,new PatternTopic(“topic”));
adapter()函数返回值是一个MessageListenerAdapter的对象。
new MessageListenerAdapter(messageReceiver, “onMessage”);第一个参数为接受消息的实体类对象(既上面定义的实体类对象,由adapter()作为参数传进来,第二个参数为实体类中定义的接收消息的方法)该语句中的两个参数一个是消息适配器,下面为配置,第二个参数是channel(既为频道),该参数由发布者提供。
3.下面实现发布者
Controller层
package com.remoteTest.cache.Controller;
import com.remoteTest.cache.service.RedisService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RequestMapping("/redis")
@RestController
public class RedisController {
@Autowired
RedisTemplate<String,String> redisTemplate;
@Autowired
RedisService redisService;
@RequestMapping("/publish")
public String sendMessage (String msg) {
return redisService.sendMessage(msg);
}
}
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Service层
package com.remoteTest.cache.service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Service;
@Service
public class RedisService {
@Autowired
RedisTemplate<String,String> redisTemplate;
public String sendMessage (String msg) {
try {
redisTemplate.convertAndSend("topic", msg);
System.out.println(msg);
return "消息发送成功";
}catch (Exception e) {
e.printStackTrace();
return "消息发送失败";
}
}
}
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redisTemplate.convertAndSend(“topic”,msg)
该方法用于发布消息,内置函数,可以直接调用,其中两个参数第一个是channle(频道,需和订阅者保持一致),第二个参数是发布的消息。
4.redis配置
#redis连接
server.port=8010
spring.redis.host=127.0.0.1
spring.redis.port=6379
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密码默认为空