Spring Boot集成RabbitMQ發送接收JSON

默認狀況下RabbitMQ發送的消息是轉換爲字節碼，這裏介紹一下如何發送JSON數據。

ObjectMapper

最簡單發送JSON數據的方式是把對象使用ObjectMapper等JSON工具類把對象轉換爲JSON格式，而後發送。以下：

@Autowired
private ObjectMapper objectMapper;

public void sendOrder(Order order) {
    try {
        String orderJson = objectMapper.writeValueAsString(order);
        Message message = MessageBuilder
                            .withBody(orderJson.getBytes())
                            .setContentType(MessageProperties.CONTENT_TYPE_JSON)
                            .build();
        this.rabbitTemplate.convertAndSend(RabbitConfig.QUEUE_ORDERS, message);
    } catch (JsonProcessingException e) {
        e.printStackTrace();
    }
}

發送JSON消息

可是在每個發送消息的地方都這樣寫就會很繁瑣。若是規定了消息的格式爲JSON，能夠使用org.springframework.amqp.support.converter.Jackson2JsonMessageConverter做爲默認的消息轉換器。

在RabbitConfig添加轉換器：

package com.lyt.rabbit.rabbitproducer;

import org.springframework.amqp.rabbit.connection.ConnectionFactory;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.amqp.support.converter.Jackson2JsonMessageConverter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class RabbitConfig {

    @Bean
    public RabbitTemplate rabbitTemplate(final ConnectionFactory connectionFactory) {
        final RabbitTemplate rabbitTemplate = new RabbitTemplate(connectionFactory);
        rabbitTemplate.setMessageConverter(producerJackson2MessageConverter());
        return rabbitTemplate;
    }

    @Bean
    public Jackson2JsonMessageConverter producerJackson2MessageConverter() {
        return new Jackson2JsonMessageConverter();
    }
}

在RabbitMQ的的管理端查看，轉換後的確實是json，headers裏包含了對象的具體類型等

接收JSON消息

爲了接收JSON數據，咱們應該經過實現RabbitListenerConfigurer來定製RabbitMQ配置。

package com.lyt.rabbit.rabbitcustomer;

import org.springframework.amqp.rabbit.annotation.RabbitListenerConfigurer;
import org.springframework.amqp.rabbit.listener.RabbitListenerEndpointRegistrar;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.messaging.converter.MappingJackson2MessageConverter;
import org.springframework.messaging.handler.annotation.support.DefaultMessageHandlerMethodFactory;
import org.springframework.messaging.handler.annotation.support.MessageHandlerMethodFactory;

@Configuration
public class RabbitConfig implements RabbitListenerConfigurer {

    @Override
    public void configureRabbitListeners(RabbitListenerEndpointRegistrar registrar) {
        registrar.setMessageHandlerMethodFactory(messageHandlerMethodFactory());
    }

    @Bean
    MessageHandlerMethodFactory messageHandlerMethodFactory() {
        DefaultMessageHandlerMethodFactory messageHandlerMethodFactory = new DefaultMessageHandlerMethodFactory();
        messageHandlerMethodFactory.setMessageConverter(consumerJackson2MessageConverter());
        return messageHandlerMethodFactory;
    }

    @Bean
    public MappingJackson2MessageConverter consumerJackson2MessageConverter() {
        return new MappingJackson2MessageConverter();
    }
}