Spring Boot集成RabbitMQ发送接收JSON

默认状况下RabbitMQ发送的消息是转换为字节码，这里介绍一下如何发送JSON数据。

ObjectMapper

最简单发送JSON数据的方式是把对象使用ObjectMapper等JSON工具类把对象转换为JSON格式，而后发送。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();
    }
}

发送JSON消息

可是在每个发送消息的地方都这样写就会很繁琐。若是规定了消息的格式为JSON，能够使用org.springframework.amqp.support.converter.Jackson2JsonMessageConverter做为默认的消息转换器。

在RabbitConfig添加转换器：

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，转换后的确实是json，headers里包含了对象的具体类型等

接收JSON消息

为了接收JSON数据，咱们应该经过实现RabbitListenerConfigurer来定制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();
    }
}