# MQ
spring.rabbitmq.host=localhost
spring.rabbitmq.port=5672
spring.rabbitmq.virtual-host=/

@Slf4j
@SpringBootTest
class OrderApplicationTests {

    @Autowired
    AmqpAdmin amqpAdmin;

    @Test
    void createExchange() {
        // 名稱, 持久, 自動刪
        DirectExchange directExchange = new DirectExchange("hello-exchange", true, false);
        amqpAdmin.declareExchange(directExchange);
        log.info("Exchange[{}]創建成功", "hello-exchange");
    }

    @Test
    void createQueue() {
        // import org.springframework.amqp.core.Queue;
        // 第三個參數 排他，若true表示隊列只能被聲明的連接綁定，其他人綁不上
        amqpAdmin.declareQueue(new Queue("hello-queue", true, false, false));
        log.info("Queue創建[{}]成功", "hello-queue");
    }

    @Test
    void createBinding() {
        // String destination目的地，隊列name或 交換機name
        // Binding.DestinationType destinationType目的地類型 queue還是exchange
        // String exchange 交換機
        // String routingKey 路由鍵
        // @Nullable Map<String, Object> arguments 自定義參數
        amqpAdmin.declareBinding(new Binding("hello-queue", Binding.DestinationType.QUEUE,"hello-exchange",
                "hello.java", null));
        log.info("Binding創建[{}]成功", "hello-binding");
    }
}

@Autowired
RabbitTemplate rabbitTemplate;

@Test
void send() {
    String msg = "一條訊息";
    rabbitTemplate.convertAndSend("hello-exchange", "hello.java", msg);
}

import org.springframework.amqp.support.converter.MessageConverter;

@Configuration
public class MyRabbitConfig {
    @Bean
    public MessageConverter messageConverter() {
        return new Jackson2JsonMessageConverter();
    }
}

@Test
void send() {
      for (int i = 0; i < 5; i++) {
        RefundInfoEntity refundInfoEntity = new RefundInfoEntity();
        refundInfoEntity.setRefundContent("test" + i);
        rabbitTemplate.convertAndSend("hello-exchange", "hello.java", refundInfoEntity);
    }
}

@RabbitListener(queues = {"hello-queue"})
void receiveMsg(Message message) {
    byte[] body = message.getBody();
    MessageProperties messageProperties = message.getMessageProperties();
    System.out.println(body);
    System.out.println("訊息頭=" + messageProperties);
}

@RabbitListener(queues = {"hello-queue"})
void receiveMsg(RefundInfoEntity content,
                Channel channel) {
    System.out.println(content);
}

@RabbitHandler
void 方法1(A類 a){...}

@RabbitHandler
void 方法2(B類 b){...}

# 開啓發送確認，確定有送到Broker
spring.rabbitmq.publisher-confirm-type=correlated

@Autowired
RabbitTemplate rabbitTemplate;

@PostConstruct // RabbitTemplate物件創建之後執行此方法
public void initRabbitTemplate() {
    rabbitTemplate.setConfirmCallback(new RabbitTemplate.ConfirmCallback() {
        /**
         * 訊息有送到訊息中心就執行此方法
         * @param correlationData 消息的唯一關聯數據，可以視為消息id
         * @param b 是否送達
         * @param s 失敗原因
         */
        @Override
        public void confirm(CorrelationData correlationData, boolean b, String s) {
            System.out.println("訊息"+correlationData+"已送達中心");

        }
    });
}

# 開啓發送確認，確定經過交換機抵達Queue
spring.rabbitmq.publisher-returns=true
# 只要抵達Queue，用異步模式優先回調return confirm
spring.rabbitmq.template.mandatory=true

rabbitTemplate.setReturnCallback(new RabbitTemplate.ReturnCallback() {
    @Override
    public void returnedMessage(Message message, int i, String s, String s1, String s2) {
        // 如果沒有到queue，要返回這些訊息
    }
});

@RabbitListener(queues = {"hello-queue"})
void receiveMsg(Message message,
                RefundInfoEntity content,
                Channel channel) {
    System.out.println(content);
    // deliveryTag在channel內按順序自增
    long deliveryTag = message.getMessageProperties().getDeliveryTag();
    // 手動簽收，後面的false = 非批量模式
    try {
        channel.basicAck(deliveryTag, false);
        System.out.println("簽收，單據流水號=" + deliveryTag);
    } catch (IOException e) {
        // 簽收失敗，例如網路異常
        e.printStackTrace();
    }
}

// 拒收，參數是: 流水號, 批次, 重新入隊列
channel.basicNack(deliveryTag, false, false); // 這樣會丟棄

// 重新入隊列=true的話，訊息會重新回到隊列
channel.basicNack(deliveryTag, false, true);
// 等同於
channel.basicReject(deliveryTag, false);