SpringBoot引入RabbitMQ（二）：關於無法消費消息的問題

本文轉載自查看原文 2022-04-20 17:15 1508

前文：SpringBoot引入RabbitMQ（一）：引入進SpringBoot中

在前文中，就出現過一次無法發送消息的問題

原因：SpringBoot在啟動時，就會自動生成配置好的Queue、Exchange、Key等等，但是如果初次啟動時只有生產者或者消費者的情況下，並不會建立他們，所以發送消息失敗。

解決：生產者、消費者都配置好之后，逐一啟動即可自動生成，然后就可以正常發送消息了

現在生產者、消費者分開放在兩個Demo中，再模擬一下收發消息

生產者：

原項目做生產者，具體搭建方法參考上文

OutSendMessageDTO

package com.zyuan.boot.rabbitmq.message.dto;


@Data
public class OutSendMessageDTO implements Serializable {

    private static final long serialVersionUID = 1L;

    private Long id;

    private String messageInfo;

}

MqConstant

public class MqConstant {public static final String OUT_SEND_MESSAGE_QUEUE = "outSendMessageQueue";
    public static final String OUT_SEND_MESSAGE_EXCHANGE = "outSendMessageExchange";
    public static final String OUT_SEND_MESSAGE_KEY = "outSendMessageKey";
}

OutSendMessageProducer

import com.zyuan.boot.rabbitmq.message.constant.MqConstant;
import com.zyuan.boot.rabbitmq.message.dto.OutSendMessageDTO;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class OutSendMessageProducer {

    @Autowired
    private RabbitTemplate rabbitTemplate;

    public void sendOutMessage(OutSendMessageDTO outSendMessageDTO) {
        System.out.println("外發了一條消息");
        try {
            rabbitTemplate.convertAndSend(MqConstant.OUT_SEND_MESSAGE_EXCHANGE, MqConstant.OUT_SEND_MESSAGE_KEY, outSendMessageDTO);
            System.out.println("外發消息成功");
        } catch (Exception e) {
            System.out.println("外發消息失敗");
            e.printStackTrace();
        }
    }

}

測試類：

@SpringBootTest
@RunWith(SpringRunner.class)
public class RabbitMqTest {
    @Autowired
    private OutSendMessageProducer outSendMessageProducer;

    @Test
    public void sendOutMessage() {
        OutSendMessageDTO outSendMessageDTO = new OutSendMessageDTO();
        outSendMessageDTO.setId(9999999L);
        outSendMessageDTO.setMessageInfo("這是外發的消息");
        outSendMessageProducer.sendOutMessage(outSendMessageDTO);
    }
}

消費者：

將OutSendMessageDTO、MqConstant復制過來

OutSendMessageConsumer

import com.rabbitmq.client.Channel;
import com.zyuan.boot.rabbitmqconsum.message.constant.MqConstant;
import com.zyuan.boot.rabbitmqconsum.message.dto.OutSendMessageDTO;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.rabbit.annotation.*;
import org.springframework.messaging.handler.annotation.Payload;
import org.springframework.stereotype.Component;

import java.io.IOException;

@Component
public class OutSendMessageConsumer {

    @RabbitListener(
            bindings = {
                    @QueueBinding(
                            value = @Queue(value = MqConstant.OUT_SEND_MESSAGE_QUEUE),
                            exchange = @Exchange(value = MqConstant.OUT_SEND_MESSAGE_EXCHANGE),
                            key = MqConstant.OUT_SEND_MESSAGE_KEY
                    )
            }
    )
    public void consumeFirstMessage(@Payload OutSendMessageDTO outSendMessageDTO, Channel channel, Message message) {
        System.out.println("消費到了外發的信息:" + outSendMessageDTO.toString());
        try {
            channel.basicAck(message.getMessageProperties().getDeliveryTag(), false);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}