Written by 🍺
on August 2, 2023

Springboot运行时动态创建队列消费者

原理

核心类是AmqpAdmin以及其实现类RabbitAdmin，这个类包含了注册queue、exchange以及binding的方法

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/**
 * Declare the given queue.
 * @param queue the queue to declare.
 * @return the name of the queue.
 */
@Nullable
String declareQueue(Queue queue);

/**
 * Declare an exchange.
 * @param exchange the exchange to declare.
 */
void declareExchange(Exchange exchange);


/**
 * Declare a binding of a queue to an exchange.
 * @param binding a description of the binding to declare.
 */
void declareBinding(Binding binding);

我们只需要注入该类到相应的Service中，即可利用这几个方法实现运行时动态注册queue，动态绑定queue和exchange；

这里要注意一个问题：注入bean的时候要用AmqpAdmin，不能用RabbitAdmin，否则注不进去。因为rabbitMq自动配置生成的地方用的是AmqpAdmin：

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public AmqpAdmin amqpAdmin(ConnectionFactory connectionFactory) {
	return new RabbitAdmin(connectionFactory);
}

完整代码

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@Service
@Slf4j
@RequiredArgsConstructor
public class MqFactory {

    private final SimpleRabbitListenerContainerFactory containerFactory;

    private final AmqpAdmin rabbitAdmin;

    private final List<MessageListenerContainer> messageListenerContainerList = new ArrayList<>();

    public void createMessageListener(String tableName) {
        log.info("- create message listener for model: {}", tableName);

        //生成队列、交换机和绑定规则，绑定key为 = data.sync.key.表名称
        Queue queue = new Queue("");
        TopicExchange exchange = new TopicExchange(EXCHANGE);
        Binding binding = BindingBuilder.bind(queue).to(exchange).with(KEY_PREFIX + tableName);
        rabbitAdmin.declareQueue(queue);
        rabbitAdmin.declareExchange(exchange);
        rabbitAdmin.declareBinding(binding);

        SimpleMessageListenerContainer container = containerFactory.createListenerContainer();
        container.setQueues(queue);
        container.setMessageListener(message -> handleMessage(tableName, message));
        container.start();

        messageListenerContainerList.add(container);
        log.info("- create message listener finish");
    }

    private void handleMessage(String tableName, Message message) {

        byte[] body = message.getBody();
        String json = new String(body);

        log.info("- handle table: {} message: {}", tableName, json);
    }


    @PreDestroy
    public void destroy() {
        messageListenerContainerList.forEach(Lifecycle::stop);
        log.info("- stop all message listeners...");
    }

}

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