SpringBoot集成RabbitMQ实现发布确认

何为发布确认？

字面意思：P发送消息之后，能够确定C收到消息了

P发送消息要通过交换机和队列，所以只需要确保这二者都不出问题，或者有PlanB来防止出意外即可

不明原因，导致交换机重启，在重启过程中，生产者投递消息失败，导致消息丢失；

交换机宕机了，没有集群

。。。

交换机和队列之间的bingKey错误，导致找不到指定队列；

队列TTL已到

。。。

交换机问题解决

交换机是否收到消息，生产者是不知道的，所以需要写一个回调方法，通知生产者，消息是否被交换机接收到

队列问题解决

交换机是否找到对应队列，交换机如果找不到对应队列，会将消息丢掉，这种情况是不允许发生的，所以需要把不可达的消息返回交换机，交给其他（备份）交换机重新发送

spring:
  rabbitmq:
    host: 127.0.0.1
    port: 5672
    username: guest
    password: guest
    publisher-/confirm/i-type: correlated       #开启发布确认 默认是关闭的
    publisher-returns: true                  #开启消息回退  交换机找不到队列时，会直接丢弃消息，回退给生产者

@Configuration
public class /confirm/iConfig {

    public static final String /confirm/i_EXCHANGE_NAME = "/confirm/i.exchange";
    public static final String /confirm/i_QUEUE_NAME = "/confirm/i.queue";

    public static final String BACKUP_EXCHANGE_NAME = "backup.exchange";
    public static final String BACKUP_QUEUE_NAME = "backup.queue";
    public static final String WARNING_QUEUE_NAME = "warning.queue";
    
    //声明确定队列
    @Bean("confirQueue")
    public Queue queue(){
        return QueueBuilder.durable(/confirm/i_QUEUE_NAME).build();
    }

    //声明业务交换机
    @Bean("confirExchange")
    public DirectExchange directExchange(){
        return ExchangeBuilder.directExchange(/confirm/i_EXCHANGE_NAME).durable(true).withArgument("alternate-exchange",BACKUP_EXCHANGE_NAME).build();
    }

    //绑定确定队列和业务交换机
    @Bean
    public Binding bindingQueueToExchange(@Qualifier("confirQueue") Queue confirQueue,
                                          @Qualifier("confirExchange")DirectExchange confirExchange){
        return BindingBuilder.bind(confirQueue).to(confirExchange).with("key1");
    }

    //声明备份 Exchange
    @Bean("backupExchange")
    public FanoutExchange backupExchange(){
        return new FanoutExchange(BACKUP_EXCHANGE_NAME);
    }
    
    //声明备份队列
    @Bean("backQueue")
    public Queue backQueue(){
        return QueueBuilder.durable(BACKUP_QUEUE_NAME).build();
    }
    //声明报警队列
    @Bean("warningQueue")
    public Queue warningQueue(){
        return QueueBuilder.durable(WARNING_QUEUE_NAME).build();
    }

    //声明备份队列和 备份交换机之间的绑定关系
    @Bean
    public Binding backupBinding(@Qualifier("backQueue") Queue queue,
                                 @Qualifier("backupExchange") FanoutExchange backupExchange){
        return BindingBuilder.bind(queue).to(backupExchange);
    }

    //声明报警队列和 备份交换机之间的绑定关系
    @Bean
    public Binding warningBinding(@Qualifier("warningQueue") Queue queue,
                                  @Qualifier("backupExchange") FanoutExchange
                                          backupExchange){
        return BindingBuilder.bind(queue).to(backupExchange);
    }
}

@Component
@Slf4j
public class MyCallBack implements RabbitTemplate./confirm/iCallback,RabbitTemplate.ReturnsCallback{
    
    @Override
    public void /confirm/i(CorrelationData correlationData, boolean ack, String s) {
        String id = correlationData!=null?correlationData.getId():"";
        if (ack){
           log.info("交换机已收到id为:{}",id);
        }else{
            log.info("交换机还未收到 id 为:{}消息,由于原因:{}",id,s);
        }
    }

    
    @Override
    public void returnedMessage(ReturnedMessage returnedMessage) {
        log.error("消息：{},被交换机:{}退回,退回原因:{},路由key:{}",returnedMessage.getMessage(),returnedMessage.getExchange(),returnedMessage.getReplyText(),returnedMessage.getRoutingKey());
    }
}

@RestController
@RequestMapping("//confirm/i")
@Slf4j
public class /confirm/iProducer {

    public static final String /confirm/i_EXCHANGE_NAME = "/confirm/i.exchange";

    @Autowired
    private RabbitTemplate rabbitTemplate;

    @Autowired
    private MyCallBack myCallBack;

    //依赖注入rabbitMQ之后再设置它的回调对象
    @PostConstruct
    public void init(){
        rabbitTemplate.set/confirm/iCallback(myCallBack);
        rabbitTemplate.setReturnsCallback(myCallBack);
    }

    //发送消息
    @GetMapping("/sendMessage/{message}")
    public void sendMessage(@PathVariable String message){
        //指定消息id为1
        CorrelationData correlationData1 = new CorrelationData("1");
        String routintKey = "key1";
        rabbitTemplate.convertAndSend(/confirm/i_EXCHANGE_NAME,routintKey,message+routintKey,correlationData1);
        log.info("发送的消息是：{}",message);
        
        //指定消息id为2
        CorrelationData correlationData2 = new CorrelationData("2");
        rabbitTemplate.convertAndSend(/confirm/i_EXCHANGE_NAME,routintKey+123,message+routintKey,correlationData2);
        log.info("发送的消息是：{}",message);
    }
}

@Component
@Slf4j
public class /confirm/iCustomer {

    public static final String /confirm/i_QUEUE_NAME = "/confirm/i.queue";

    @RabbitListener(queues = /confirm/i_QUEUE_NAME)
    public void receiveMsg(Message message){
        String msg = new String(message.getBody());
        log.info("接收确定队列传来的消息：{}",msg);
    }
}

@Component
@Slf4j
public class WarningConsumer {

    public static final String WARNING_QUEUE_NAME = "warning.queue";

    @RabbitListener(queues = WARNING_QUEUE_NAME)
    public void receiveWarningMsg(Message message) {
        String msg = new String(message.getBody());
        log.error("报警发现不可路由消息：{}", msg);
    }
}

http://localhost:8080//confirm/i/sendMessage/你爱我，我爱你