RabbitMQ实现消费端限流的步骤

@Configuration
public class DirectRabbitConfig {
    public static final String DEAD_LETTER_EXCHANGE = "dead.latter.exchange";
    public static final String DEAD_LETTER_QUEUE = "dead.latter.queue";
    public static final String DEAD_LETTER_KEY = "dead.latter.key";
    //队列 起名：TestDirectQueue
    @Bean
    public Queue TestDirectQueue() {
        //实例化队列时各个参数的含义如下：
        //name:队列名称
        // durable:是否持久化,默认是false,持久化队列：会被存储在磁盘上，当消息代理重启时仍然存在，暂存队列：当前连接有效
        // exclusive:默认也是false，只能被当前创建的连接使用，而且当连接关闭后队列即被删除。此参考优先级高于durable
        // autoDelete:默认是false,是否自动删除，当没有生产者或者消费者使用此队列，该队列会自动删除。
        //一般设置一下队列的持久化就好,其余两个就是默认false（消息和交换机也可以持久化，但是消息持久化的前提是需要和队列，交换机持久化一起使用）
        //为业务队列绑定一个死信交换机，当业务队列里的消息过期了就被转发到死信交换机，再由死信交换机发给死信队列处理
//        Map<String, Object> args = new HashMap<>(2);
//       x-dead-letter-exchange    这里声明当前队列绑定的死信交换机
//        args.put("x-dead-letter-exchange", DEAD_LETTER_EXCHANGE);
//       x-dead-letter-routing-key  这里声明当前队列的死信路由key
//        args.put("x-dead-letter-routing-key", DEAD_LETTER_KEY);
        //5000毫秒
//        args.put("x-message-ttl", 5000);
//        return new Queue("TestDirectQueue",false,false,false,args);
        return new Queue("TestDirectQueue",false,false,false);
    }
    //Direct交换机 起名：TestDirectExchange
    @Bean
    DirectExchange TestDirectExchange() {
        return new DirectExchange("TestDirectExchange",true,false);
    }
    //绑定  将队列和交换机绑定, 并设置用于匹配键：TestDirectRouting
    @Bean
    Binding bindingDirect() {
        return BindingBuilder.bind(TestDirectQueue()).to(TestDirectExchange()).with("TestDirectRouting");
    }
    /**
     * ========================死信队列==================================
     */
    // 声明死信Exchange
    @Bean
    public DirectExchange deadLetterExchange(){
        return new DirectExchange(DEAD_LETTER_EXCHANGE);
    }
    // 声明死信队列A
    @Bean
    public Queue deadLetterQueueA(){
        return new Queue(DEAD_LETTER_QUEUE);
    }
    @Bean
    public Binding deadLetterBindingA(){
        return BindingBuilder.bind(deadLetterQueueA()).to(deadLetterExchange()).with(DEAD_LETTER_KEY);
    }
}
@Component
@RabbitListener(queues = "TestDirectQueue")//监听的队列名称 TestDirectQueue
public class DirectReceiver {
     Integer index = 0;
    @RabbitHandler
    public void process(Channel channel,String msg) throws Exception {
        ++index;
        channel.basicQos(0, 1, false);
        //设置非自动ack
        DefaultConsumer consumer = new DefaultConsumer(channel);
        channel.basicConsume("TestDirectQueue", false,consumer);
        //假设业务处理需要3秒，那么当消费者接受到消息的时候，只处理一条，且要处理3秒，那么在服务器堆积的多条信息就不会疯狂涌入
        Thread.sleep(3000);
        System.out.println(" DirectReceiver消费者收到消息  : " + msg + "，第" +index+ "条"+"======"+ new Date().toString());
    }
}

import com.rabbitmq.client.*;
public class Consumer {
    private final static String QUEUE_NAME = "queue_name";
    public static void main(String[] argv) throws Exception {
        ConnectionFactory factory = new ConnectionFactory();
        factory.setHost("localhost");
        Connection connection = factory.newConnection();
        Channel channel = connection.createChannel();
        channel.queueDeclare(QUEUE_NAME, false, false, false, null);
        int prefetchCount = 5; // 设置预取值为 5
        channel.basicQos(prefetchCount);
        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println("Received: " + message);
            // 模拟消息处理
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false); // 手动应答消息
        };
        channel.basicConsume(QUEUE_NAME, false, deliverCallback, consumerTag -> { });
    }
}