消息转换器
Spring的对消息对象的处理是由org.springframework.amqp.support.converter.MessageConverter来处理的。而默认实现是SimpleMessageConverter,基于JDK的ObjectOutputStream完成序列化。
存在下列问题:
- JDK的序列化有安全风险
- JDK序列化的消息太大
- JDK序列化的消息可读性差
JSON序列化
建议采用JSON序列化代替默认的JDK序列化,要做两件事情:
在publisher和consumer中都要引入jackson依赖:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
</dependency>
在publisher和consumer中都要配置MessageConverter:
@Bean
public MessageConverter messageConverter(){
return new Jackson2JsonMessageConverter();
}
案例
@Test
public void testMapQueue() {
//队列名称
String queueName = "map.queue";
//消息
HashMap<String, Object> ssm = new HashMap<>();
ssm.put("name","xiao");
ssm.put("age",19);
//发送消息
rabbitTemplate.convertAndSend(queueName, ssm);
}
@RabbitListener(queues = "map.queue")
public void listenMapQueue1(Object msg) throws InterruptedException{
System.out.println("消费者1收到了 map.queue的消息:["+msg+"]");
//Thread.sleep(200);
}
业务改造
需求:改造余额支付功能,不再同步调用交易服务的OpenFeign接口,而是采用异步MQ通知交易服务更新订单状态。
//监听的交易服务
@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "mark.order.pay.queue"),exchange = @Exchange(name = "pay.topic",type = ExchangeTypes.TOPIC),key = {"pay.success"}))
public void listenPayQueue(String msg){
//这里可以直接调用service层
System.out.println("交易服务收到了消息:["+msg+"]");
}
//监听的通知服务
@RabbitListener(bindings = @QueueBinding(value = @Queue(name = "pay.notify.queue"),exchange = @Exchange(name = "pay.topic",type = ExchangeTypes.TOPIC),key = {"pay.#"}))
public void listenNotifyQueue(String msg){
//这里可以直接调用service层
System.out.println("通知服务收到了消息:["+msg+"]");
}
下面修该生产者的serviceImpl代码,改同步调用为异步调用
try(){
rabbitTemplate.convertAndSend("pay.topic","pay.success","202405200002");
}catch(Exception e){
e.printStackTrace();
}