@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";
    //隊列 起名：TestDirectQueue
    @Bean
    public Queue TestDirectQueue() {
        //實例化隊列時各個參數的含義如下：
        //name:隊列名稱
        // durable:是否持久化,默認是false,持久化隊列：會被存儲在磁盤上，當消息代理重啟時仍然存在，暫存隊列：當前連接有效
        // exclusive:默認也是false，只能被當前創(chuàng)建的連接使用，而且當連接關閉后隊列即被刪除。此參考優(yōu)先級高于durable
        // autoDelete:默認是false,是否自動刪除，當沒有生產者或者消費者使用此隊列，該隊列會自動刪除。
        //一般設置一下隊列的持久化就好,其余兩個就是默認false（消息和交換機也可以持久化，但是消息持久化的前提是需要和隊列，交換機持久化一起使用）
        //為業(yè)務隊列綁定一個死信交換機，當業(yè)務隊列里的消息過期了就被轉發(fā)到死信交換機，再由死信交換機發(fā)給死信隊列處理
//        Map<String, Object> args = new HashMap<>(2);
//       x-dead-letter-exchange    這里聲明當前隊列綁定的死信交換機
//        args.put("x-dead-letter-exchange", DEAD_LETTER_EXCHANGE);
//       x-dead-letter-routing-key  這里聲明當前隊列的死信路由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交換機 起名：TestDirectExchange
    @Bean
    DirectExchange TestDirectExchange() {
        return new DirectExchange("TestDirectExchange",true,false);
    }
    //綁定  將隊列和交換機綁定, 并設置用于匹配鍵：TestDirectRouting
    @Bean
    Binding bindingDirect() {
        return BindingBuilder.bind(TestDirectQueue()).to(TestDirectExchange()).with("TestDirectRouting");
    }
    /**
     * ========================死信隊列==================================
     */
    // 聲明死信Exchange
    @Bean
    public DirectExchange deadLetterExchange(){
        return new DirectExchange(DEAD_LETTER_EXCHANGE);
    }
    // 聲明死信隊列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")//監(jiān)聽的隊列名稱 TestDirectQueue
public class DirectReceiver {
     Integer index = 0;
    @RabbitHandler
    public void process(Channel channel,String msg) throws Exception {
        ++index;
        channel.basicQos(0, 1, false);
        //設置非自動ack
        DefaultConsumer consumer = new DefaultConsumer(channel);
        channel.basicConsume("TestDirectQueue", false,consumer);
        //假設業(yè)務處理需要3秒，那么當消費者接受到消息的時候，只處理一條，且要處理3秒，那么在服務器堆積的多條信息就不會瘋狂涌入
        Thread.sleep(3000);
        System.out.println(" DirectReceiver消費者收到消息  : " + msg + "，第" +index+ "條"+"======"+ 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; // 設置預取值為 5
        channel.basicQos(prefetchCount);
        DeliverCallback deliverCallback = (consumerTag, delivery) -> {
            String message = new String(delivery.getBody(), "UTF-8");
            System.out.println("Received: " + message);
            // 模擬消息處理
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false); // 手動應答消息
        };
        channel.basicConsume(QUEUE_NAME, false, deliverCallback, consumerTag -> { });
    }
}