Rabbitmq解决分布式事务demo

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核心思路

补单队列和主程序不在一台机器
1、使用扇形交换机
2、生成者只需要发送消息到交换机，扇形交换机让绑定的队列进行消费
3、派单消费者正常消费，补单消费者做好幂等性，在主程序报错的情况下进行补单操作

核心代码

1.配置信息，必须开启生产者消息确认机制

spring:
  rabbitmq:
    host: 10.211.55.16
    port: 5672
    username: jarye
    password: 123456
    virtual-host: /mytest1205
    ###开启消息确认机制 confirms
    publisher-confirms: true
    publisher-returns: true
    listener:
      simple:
        retry:
          enabled: true
          max-attempts: 5
          initial-interval: 3000ms
        acknowledge-mode: manual

2.生产者必须继承ConfirmCallback，保证消息的可达性，消费者不确认的话则手动重试

@Component
@Slf4j
public class OrderProducer implements RabbitTemplate.ConfirmCallback {
    @Autowired
    private OrderMapper orderMapper;
    @Autowired
    private RabbitTemplate rabbitTemplate;

    @Transactional
    public String send() {
        // 1.创建订单
        String orderId = System.currentTimeMillis() + "";
        UserEntity orderEntity = createOrder(orderId);
        //2.将订单添加到数据库中(步骤一 先往数据库中添加一条数据)
        int result = orderMapper.addOrder(orderEntity);
        if (result <= 0) {
            return orderId;
        }
        //3.使用消息中间件异步 ，分配订单
        String sendMsgJson = JSONObject.toJSONString(orderEntity);
        send(sendMsgJson);
        //抛出异常，让本地回滚，但消息已经发送
        int i = 1 / 0;
        return orderId;
    }

    public UserEntity createOrder(String orderId) {
        UserEntity orderEntity = new UserEntity();
        orderEntity.setName("张三");
        orderEntity.setId(1L);
        // 价格是300元
        orderEntity.setAge(18);
        return orderEntity;
    }

    private void send(String sendMsg) {
        log.info(">>>生产者发送订单数据:" + sendMsg);
        // 设置生产者消息确认机制
        this.rabbitTemplate.setMandatory(true);
        this.rabbitTemplate.setConfirmCallback(this);
        // 构建回调返回参数
        CorrelationData correlationData = new CorrelationData(sendMsg);
        rabbitTemplate.convertAndSend(RabbitMQConfig.ORDER_EXCHANGE_NAME, "", sendMsg, correlationData);
    }

    @Override
    public void confirm(CorrelationData correlationData, boolean ack, String s) {
        String sendMsg = correlationData.getId();
        System.out.println("生产者开始消息确认orderId:" + sendMsg);
        //如果没有发送成功，则考虑重试
        if (!ack) {
            //递归调用发送，可以考虑重试次数
            send(sendMsg);
            return;
        }
        System.out.println("生产者消息确认orderId:" + sendMsg);
    }
}

3.消费者保证幂等性及手动消息确认

@Component
public class DistriLeafleConsumer {

    @RabbitListener(queues = "order_dic_queue")
    public void distriLeafleConsumer(Message message, Channel channel) throws IOException {
        String msg = new String(message.getBody());
        System.out.println("派代服务平台消费msg:" + msg);
        JSONObject jsonObject = JSONObject.parseObject(msg);
        // 订单id
        String orderId = jsonObject.getString("orderId");
        // 手动ack 删除该消息
        channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
        // 假设派单userID 1234
//        Long userId = 1234L;
       /* DispatchEntity dispatchEntity = new DispatchEntity(orderId, userId);
        int result = dispatchMapper.insertDistribute(dispatchEntity);
        if (result >= 0) {
            // 手动ack 删除该消息
            channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
        }*/

    }
}

@Component
public class CreateOrderConsumer {
    @Autowired
    private OrderMapper orderMapper;

    @RabbitListener(queues = "order_create_queue")
    public void createOrderConsumer(Message message, Channel channel) throws IOException {
        String msg = new String(message.getBody());
        System.out.println("补单服务平台消费msg:" + msg);
        UserEntity orderEntity = JSONObject.parseObject(msg, UserEntity.class);
        Long orderId = orderEntity.getId();
        // 根据订单号码查询该笔订单是否创建
        UserEntity dbOrderEntity = orderMapper.findOrderId(orderId);
        if (dbOrderEntity != null) {
            // 手动ack 删除该消息
            channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
            return;
        }
        int result = orderMapper.addOrder(orderEntity);
        if (result >= 0) {
            // 手动ack 删除该消息
            channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
        }
    }
}

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