非同步

客戶端請求不會阻塞程序，服務端的響應可以是非即時的

RabbitMQ的簡單使用

1.新增依賴

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-amqp</artifactId>
        </dependency>

2.建立接收器

@Slf4j
@Component
public class MqReceiver {

    //1.無法自動建立，需要在Rabbit控制面板自己建立佇列@RabbitListener(queues = "myQueue")
    //2.自動建立佇列@RabbitListener(queuesToDeclare = @Queue("myQueue"))
    //3.自動建立，Exchange和Queue繫結
    @RabbitListener(bindings = @QueueBinding(
            exchange = @Exchange("myExchange"),
            value = @Queue("myQueue")

    ))
    public void process(String message) {
        log.info("MqReceiver: {}", message);
    }

    @RabbitListener(bindings = @QueueBinding(
            exchange = @Exchange("myOrder"),
            key = "computer",
            value = @Queue("computerOrder")

    ))
    public void processComputer(String message) {
        log.info("computer MqReceiver: {}", message);
    }

    @RabbitListener(bindings = @QueueBinding(
            exchange = @Exchange("myOrder"),
            key = "fruit",
            value = @Queue("fruitOrder")
    ))
    public void processFruit(String message) {
        log.info("fruit MqReceiver: {}", message);
    }
}
 

3.測試

@RunWith(SpringRunner.class)
@SpringBootTest
public class OrderApplicationTests {

	@Test
	public void contextLoads() {
	}

}
@Component
public class MqSenderTest extends OrderApplicationTests {

    @Autowired
    private AmqpTemplate amqpTemplate;

    @Test
    public void send() {
        amqpTemplate.convertAndSend("myQueue", "now " + new Date());
    }

    @Test
    public void sendOrder() {
        amqpTemplate.convertAndSend("myOrder", "computer", "now " + new Date());
    }
}
 

Spring Cloud Stream

1.引入依賴

<dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-stream-rabbit</artifactId>
        </dependency>

2.定義input和output介面

public interface StreamClient {

    String INPUT = "input";

    String OUTPUT = "output";

    String INPUT2 = "input2";

    String OUTPUT2 = "output2";

    @Input(StreamClient.INPUT)
    SubscribableChannel input();

    @Output(StreamClient.OUTPUT)
    MessageChannel output();

    @Input(StreamClient.INPUT2)
    SubscribableChannel input2();

    @Output(StreamClient.OUTPUT2)
    MessageChannel output2();
}
 

3.訊息接收類

@Component
@EnableBinding(StreamClient.class)
@Slf4j
public class StreamReceiver {

    @StreamListener(StreamClient.INPUT)
    // 通知回撥
    @SendTo(StreamClient.INPUT2)
    public String process(OrderDTO message) {
        log.info("StreamReceiver: {}", message);
        // 傳送MQ訊息
        return "received";
    }

    @StreamListener(StreamClient.INPUT2)
    public void process2(String message) {
        log.info("StreamReceiver2: {}", message);
    }
}

4.配置

spring:
    stream:
      bindings:
        input:
          destination: myMessage
          # 通過json格式傳遞資料
          content-type: application/json
          # 訊息分組，把一個服務劃到一個組裡，無論你起了多少個例項，只會有一個例項消費
          group: order
        output:
          destination: myMessage
          content-type: application/json
          group: order
        input2:
          destination: myMessage2
          content-type: application/json
          group: order
        output2:
          destination: myMessage2
          content-type: application/json
          group: order

5.呼叫

@RestController
public class SendMessageController {

    @Autowired
    private StreamClient streamClient;

    @GetMapping("/sendMessage")
    public void process() {
        OrderDTO orderDTO = new OrderDTO();
        orderDTO.setOrderId("123456");
        streamClient.output().send(MessageBuilder.withPayload(orderDTO).build());
    }

}

StreamReceiver: OrderDTO(orderId=123456, buyerName=null, buyerPhone=null, buyerAddress=null, buyerOpenid=null, orderAmount=null, orderStatus=null, payStatus=null, orderDetailList=null) StreamReceiver2: received