Spring Cloud Stream是Spring Cloud的元件之一，是一個為微服務應用構建訊息驅動能力的框架。

1、匯入引用

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-stream-rabbit</artifactId>

        </dependency>

　　

2、定義介面

public interface StreamClient {

    String INPUT = "input";

    String OUTPUT = "output";

    @Input(INPUT)

    SubscribableChannel input();

    @Output(OUTPUT)

    MessageChannel output();

}

　　

　　

3、定義訊息的接收

import lombok.extern.slf4j.Slf4j;

import org.springframework.cloud.stream.annotation.EnableBinding;

import org.springframework.cloud.stream.annotation.StreamListener;

import org.springframework.messaging.handler.annotation.SendTo;

import org.springframework.stereotype.Component;

@Component

@EnableBinding(StreamClient.class)

@Slf4j

public class StreamReceiver {

    @StreamListener(StreamClient.INPUT)

    @SendTo(StreamClient.OUTPUT)

    public Object processInput(String message){

        log.info("Input StreamReceiver:{}", message );

        return  message;

    }

    @StreamListener(StreamClient.OUTPUT)

    public void processOutPut(String message){

        log.info("Output StreamReceiver:{}", message );

    }

}

　　

4、定義訊息的傳送

@RestController

public class SendMessageController {

    @Autowired

    private StreamClient streamClient;

    @GetMapping("/sendMessage")

    public void process(){

        String msg = "hello world";

        streamClient.output().send(MessageBuilder.withPayload(msg).build());

    }

}

　　

5. 結果

　6、傳送物件

1） 傳送者

   /**

     * 傳送物件

     */

    @GetMapping("/sendMessage2")

    public void process2(){

        OrderDTO orderDTO = new OrderDTO();

        orderDTO.setOrderId("123");

        streamClient.output().send(MessageBuilder.withPayload(orderDTO).build());

    }

　　

2）接收者

  @StreamListener(StreamClient.OUTPUT)

    public void processOutPut(OrderDTO message){

        log.info("Output StreamReceiver:{}", message.toString() );

    }

　　

7、訊息接收到後，再回復訊息。使用SendTo

    @StreamListener(StreamClient.INPUT)

    @SendTo(StreamClient.OUTPUT) //當Input接收到訊息後，回覆訊息給Output

    public Object processInput(String message){

        log.info("Input StreamReceiver:{}", message );

        return  message;

    }