将RocketMQ集成到了Spring Boot项目中，实现站内信功能

1. 添加依赖

首先，在pom.xml中添加RocketMQ的依赖：

<dependencies><!-- Spring Boot Starter Web --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!-- Spring Boot Starter Data JPA --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jpa</artifactId></dependency><!-- H2 Database (或你选择的其他数据库) --><dependency><groupId>com.h2database</groupId><artifactId>h2</artifactId><scope>runtime</scope></dependency><!-- Redis Cache --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-redis</artifactId></dependency><!-- RocketMQ --><dependency><groupId>org.apache.rocketmq</groupId><artifactId>rocketmq-spring-boot-starter</artifactId><version>2.2.1</version></dependency>
</dependencies>

2. 配置文件

在application.properties中配置RocketMQ的相关信息：

# Redis Configuration
spring.redis.host=localhost
spring.redis.port=6379# RocketMQ Configuration
rocketmq.name-server=localhost:9876
rocketmq.producer.group=my-producer-group

3. 数据模型

定义Message实体类：

package com.example.inbox.model;import javax.persistence.*;
import java.time.LocalDateTime;@Entity
public class Message {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private Long id;private String senderId;private String receiverId;private String subject;private String body;private LocalDateTime timestamp;private boolean read;// Getters and Setters
}

4. Repository接口

创建MessageRepository接口：

package com.example.inbox.repository;import com.example.inbox.model.Message;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;@Repository
public interface MessageRepository extends JpaRepository<Message, Long> {
}

5. Service层

在Service层中集成缓存和RocketMQ的消息发送与接收：

package com.example.inbox.service;import com.example.inbox.model.Message;
import com.example.inbox.repository.MessageRepository;
import org.apache.rocketmq.spring.core.RocketMQTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;import java.util.List;@Service
public class MessageService {@Autowiredprivate MessageRepository messageRepository;@Autowiredprivate RocketMQTemplate rocketMQTemplate;@Cacheable(value = "messages", key = "#receiverId")public List<Message> getMessagesByReceiver(String receiverId) {return messageRepository.findByReceiverId(receiverId);}@CacheEvict(value = "messages", key = "#message.receiverId")public void sendMessage(Message message) {rocketMQTemplate.convertAndSend("messageTopic", message);}
}

6. 消息监听器

创建一个监听器来处理来自RocketMQ的消息：

package com.example.inbox.listener;import com.alibaba.fastjson.JSON;
import com.example.inbox.model.Message;
import com.example.inbox.service.MessageService;
import org.apache.rocketmq.spring.annotation.RocketMQMessageListener;
import org.apache.rocketmq.spring.core.RocketMQListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;@Component
@RocketMQMessageListener(topic = "messageTopic", consumerGroup = "my-consumer-group")
public class MessageListener implements RocketMQListener<String> {@Autowiredprivate MessageService messageService;@Overridepublic void onMessage(String messageJson) {Message message = JSON.parseObject(messageJson, Message.class);message.setTimestamp(java.time.LocalDateTime.now());messageService.saveMessage(message);}
}

7. Controller

创建Controller来处理HTTP请求：

package com.example.inbox.controller;import com.example.inbox.model.Message;
import com.example.inbox.service.MessageService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;import java.util.List;@RestController
@RequestMapping("/messages")
public class MessageController {@Autowiredprivate MessageService messageService;@GetMapping("/{receiverId}")public List<Message> getMessages(@PathVariable String receiverId) {return messageService.getMessagesByReceiver(receiverId);}@PostMappingpublic void sendMessage(@RequestBody Message message) {messageService.sendMessage(message);}
}

8. 启动类

确保你的Spring Boot应用启动类包含必要的注解：

package com.example.inbox;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;@SpringBootApplication
@EnableCaching
public class InboxApplication {public static void main(String[] args) {SpringApplication.run(InboxApplication.class, args);}
}