rocketmq 5.13任意时间延迟消息

原理是采用timewhile 实现的，源码分析可以参考
https://blog.csdn.net/sinat_14840559/article/details/129266105

除了useDelayLevel 已经默认改为false

private boolean useDelayLevel = false;

官方示意代码在public class TimerMessageProducer

for (int i = 0; i < totalMessagesToSend; i++) {
            Message message = new Message(TOPIC, ("Hello scheduled message " + i).getBytes(StandardCharsets.UTF_8));
            // This message will be delivered to consumer 10 seconds later.
            //message.setDelayTimeSec(10);
            // The effect is the same as the above
            // message.setDelayTimeMs(10_000L);
            // Set the specific delivery time, and the effect is the same as the above
            message.setDeliverTimeMs(System.currentTimeMillis() + 10_000L);
            // Send the message
            SendResult result = producer.send(message);
            System.out.printf(result + "\n");
        }

实际测试大部分都会提前几百毫秒发送消息。

ps：
message.getBornTimestamp() – 消息生成时间
message.getDeliverTimeMs()-- 消息触发时间，即delay设置的timestamp

可以使用以下代码验证

consumer.registerMessageListener((MessageListenerConcurrently) (messages, context) -> {
            for (MessageExt message : messages) {
                // Print approximate delay time period
                String body = new String(message.getBody());

                System.out.printf("Receive message[msgId=%s %d ,%d  ms later ]\n", body,

                        System.currentTimeMillis() - message.getBornTimestamp(),
                        System.currentTimeMillis() - message.getDeliverTimeMs() );
            }
            return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
        });

proxy 配置如下：

{
  "rocketMQClusterName": "DefaultCluster",
  "useDelayLevel":"false"
}