【SpringBoot】【分布式事务】【RocketMQ】整合消息队列，从单机到集群

爱被打了一巴掌 2022-11-26 10:59 181阅读 0赞

**分布式事务基本概念：**   [https://blog.csdn.net/Timeguys/article/details/107646845][https_blog.csdn.net_Timeguys_article_details_107646845]

**一、使用：**

> **一、引入依赖：**
> 
>     <dependency>
>                 <groupId>org.apache.rocketmq</groupId>
>                 <artifactId>rocketmq-spring-boot-starter</artifactId>
>                 <version>2.0.3</version>
>             </dependency>
> 
> **二、举例：生产者创建订单---->生产者发送消息----->MQ服务接受消息----->消费者监听消息并减库存**
> 
> 【生产者】：
> 
> application.yml
> 
>     rocketmq:
>       name-server: 192.168.85.128:9876 # rocketMQ地址
>       producer:
>         group: producer-group-test  # 生产者的组名需要和消费者监听consumerGroup一致
> 
> 业务代码：
> 
>     @Service
>     public class OrderServiceImpl extends ServiceImpl<OrderMapper, TbOrder> implements OrderService {
>     
>         @Resource
>         private RocketMQTemplate rocketMQTemplate;
>     
>         @Override
>         public void create() {
>             //创建订单--> 发送消息 --> 消息发送成功后调用本地事务提交 -->
>             TbOrder order = new TbOrder();
>             order.setCount(10);
>             order.setMoney(BigDecimal.valueOf(10));
>             order.setProductId(1L);
>             order.setStatus(1);
>             order.setUserId(1L);
>             sendMsg(order);
>         }
>         @Override
>         public void sendMsg(TbOrder order){
>             /**
>              * String txProducerGroup, 生产者分组
>              * String destination,  topic
>              *  Message<?> message, 消息
>              *  Object arg  消息参数
>              */
>             Message<String> build = MessageBuilder.withPayload(JSONObject.toJSONString(order)).build();
>             rocketMQTemplate.sendMessageInTransaction("tx-producer-group","txmsg-topic",build , null);
>         }
>     }
> 
> 创建  **ProducerTxmsgListener** 并实现 **RocketMQLocalTransactionListener：**
> 
>     @Component
>     // txProducerGroup 的值和发送事务消息指定的 txProducerGroup 相同 
>     @RocketMQTransactionListener(txProducerGroup = "txmsg-producer-group")
>     public class ProducerTxmsgListener implements RocketMQLocalTransactionListener {
>         @Resource
>         private OrderService orderService;
>     
>         /**
>          * @Description: 执行本地事务提交
>          */
>         @Override
>         @Transactional
>         public RocketMQLocalTransactionState executeLocalTransaction(Message message, Object o) {
>             try {
>                 TbOrder tbOrder = JSONObject.parseObject(message.getPayload().toString(), TbOrder.class);
>                 System.out.println(tbOrder);
>                 orderService.save(tbOrder);
>                 return RocketMQLocalTransactionState.COMMIT; //变更消息状态为：可消费
>             }catch (Exception e){
>                 return RocketMQLocalTransactionState.ROLLBACK; //本地事务执行异常，将消息遗弃
>             }
>         }
>     
>         /**
>          * @Description: 检查本地事务是否执行成功
>          */
>         @Override
>         public RocketMQLocalTransactionState checkLocalTransaction(Message message) {
>     
>             TbOrder tbOrder = JSONObject.parseObject(message.getPayload().toString(), TbOrder.class);
>             TbOrder order = orderService.getById(tbOrder.getId());
>             // 不为null 则表示执行成功
>             if (order != null){
>                 return RocketMQLocalTransactionState.COMMIT; //变更消息状态为：可消费
>             }
>             // 执行本地事务发生问题或还没执行完成, UNKNOWN 表示会继续回查
>             return RocketMQLocalTransactionState.UNKNOWN;
>         }
>     }
> 
> 【消费者】：
> 
> application.yml
> 
>     rocketmq:
>       name-server: 127.0.0.1:9876 # rocketMQ地址
>       producer:
>         group: producer-test-group  # 生产者的组名需要和消费者监听consumerGroup一致
> 
> 创建MyListener 并实现 RocketMQListener 接口：
> 
>     // topic 对应生产者发消息是的topic
>     @RocketMQMessageListener(topic = "test-topic" , consumerGroup = "consumer-group")
>     public class MyListener implements RocketMQListener<String> {
>     
>         @Override
>         public void onMessage(String message) {
>             //执行 减库存业务  如果发生异常，则消息会隔段时间再次消费 
>             System.out.println(message);
>         }
>     }
> 
>

### **原理图：** ###

**![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RpbWVndXlz_size_16_color_FFFFFF_t_70][]**

[https_blog.csdn.net_Timeguys_article_details_107646845]: https://blog.csdn.net/Timeguys/article/details/107646845
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RpbWVndXlz_size_16_color_FFFFFF_t_70]: /images/20221124/4eaceb5883e7431c9611456059678a8c.png