String msg = RandomStringUtils.randomAlphanumeric(6);
//常規寫法
MessageProperties messageProperties = new MessageProperties();
messageProperties.setMessageId(UUID.randomUUID().toString());
messageProperties.setContentType(CONTENT_TYPE_TEXT_PLAIN);
messageProperties.setContentEncoding("utf8");
Message message 
 
= new Message(msg.getBytes(), messageProperties);
rabbitTemplate.convertAndSend(topicExchange,"demo.email.x",message);

//lambda 表示式寫法
@FunctionalInterface
public interface MessagePostProcessor {
    Message postProcessMessage(Message var1) throws AmqpException;

    default Message postProcessMessage(Message message, Correlation correlation) {
        
 
return this.postProcessMessage(message);
    }
}
//MessagePostProcessor 是函式介面，可以上lambda
rabbitTemplate.convertAndSend(topicExchange,"demo.email.x",msg,messages->{
    messages.getMessageProperties().setMessageId(UUID.randomUUID().toString());
    messages.getMessageProperties().setContentType(CONTENT_TYPE_TEXT_PLAIN);
    messages.getMessageProperties().setContentEncoding(CharEncoding.UTF_8);
    
 
return messages;
});