rocketmq发送事务消息学习笔记

1. 添加依赖

   <dependency>
       <groupId>com.alibaba.cloudgroupId>
       <artifactId>spring-cloud-starter-stream-rocketmqartifactId>
   dependency>
   

生产消息端开发

1. 添加注解：无
2. 添加配置

   spring.cloud.stream.rocketmq.binder.name-server=192.168.221.128:9876
   

3. 发送事务消息-预提交

   @Autowired
   private RocketMQTemplate rocketMQTemplate;
   @Autowired
   private ObjectMapper objectMapper ;
   
   @GetMapping("/transactional")
   public String transactional() throws JsonProcessingException {
       Order order = new Order("123", "浙江杭州") ;
       String transactionId = UUID.randomUUID().toString() ;
       String payload = objectMapper.writeValueAsString(order);
       MessageBuilder builder = MessageBuilder.withPayload(payload)
               .setHeader(RocketMQHeaders.TRANSACTION_ID, transactionId) ;
       Message message = builder.build() ;
       // 这这里的OrderTransactionGroup 与RocketMQTransactionListener中的txProducerGroup保持一致
       TransactionSendResult sendResult = rocketMQTemplate.sendMessageInTransaction(
               "OrderTransactionGroup", "TopicOrder", message, order.getOrderId());
       return sendResult.getMsgId();
   }
   

4. 执行本地事务，提交或回滚事务消息

   // 实现RocketMQLocalTransactionListener接口，使用@RocketMQTransactionListener注解用于接收本地事务的监听
   // txProducerGroup是事务分组名称，和前面定义的OrderTransactionGroup保持一致,
   @Slf4j
   @Component
   @RocketMQTransactionListener(txProducerGroup = "OrderTransactionGroup")
   public class TransactionMsgListener implements RocketMQLocalTransactionListener {
   
       @Autowired
       private ObjectMapper objectMapper ;
   
       @Override
       public RocketMQLocalTransactionState executeLocalTransaction(Message msg, Object arg) {
           try {
               // 获取前面生成的事务id
               String transactionId = (String) msg.getHeaders().get(RocketMQHeaders.TRANSACTION_ID) ;
               // 以事务id为主键，执行本地事务
               byte [] payload = (byte[]) msg.getPayload();
               Order order = objectMapper.readValue(payload, Order.class) ;
               boolean result = this.saveOrder(order, transactionId) ;
               return result ? RocketMQLocalTransactionState.COMMIT : RocketMQLocalTransactionState.ROLLBACK;
           }catch (Exception e){
               log.error("transaction error : ", e);
               return RocketMQLocalTransactionState.ROLLBACK ;
           }
       }
   
       // 数据库业务事务方法
       private boolean saveOrder(Order order, String transactionId) {
           // 将事务ID设置为唯一键
           // 调用数据库 insert to 订单表
           return true ;
       }
   
       @Override
       public RocketMQLocalTransactionState checkLocalTransaction(Message msg) {
           // 获取事务id
           String transactionId = (String) msg.getHeaders().get(RocketMQHeaders.TRANSACTION_ID) ;
           // 以事务id为主键，查询本地事务主执行情况
           if (isSuccess(transactionId)){
               return RocketMQLocalTransactionState.COMMIT ;
           }
           return RocketMQLocalTransactionState.ROLLBACK;
       }
   
       private boolean isSuccess(String transactionId) {
           // 查询数据库 select from 订单表
           return true ;
       }
   }
   

消费消息端开发

1. 添加注解

   @EnableBinding({Sink.class})
   

2. 添加配置

   spring.cloud.stream.rocketmq.binder.name-server=192.168.221.128:9876
   spring.cloud.stream.bindings.input.destination=TopicOrder
   spring.cloud.stream.bindings.input.group=test-group1
   

3. 接收事务消息

    @StreamListener(Sink.INPUT)
    public void receive(String receiveMsg){
       log.info("TopicTest receive : {}, receiveTime = {}", receiveMsg, System.currentTimeMillis());
    }
   

4. 注意事项

   注意需要使用web项目，rocketmq会使用,否则接到消息时会报错：
   Dispatcher has no subscribers for channel 'application.input'.;
   nested exception is org.springframework.integration.MessageDispatchingException:
   Dispatcher has no subscribers, failedMessage=GenericMessage
work.integration.MessageDispatchingException:
   Dispatcher has no subscribers, failedMessage=GenericMessage