有以下3種方式發送RocketMQ消息

• 可靠同步發送 reliable synchronous
• 可靠異步發送 reliable asynchronous
• 單向發送 one-way transmission

可靠同步發送

主要運用在比較重要一點消息傳遞/通知等業務

public class SyncProducer {
    public static void main(String[] args) throws Exception {
        DefaultMQProducer producer = new
            DefaultMQProducer("test");
        producer.start();
        
 
for (int i = 0; i < 100; i++) {
            Message msg = new Message("TopicTest" /* Topic */,
                "TagA" /* Tag */,
                ("Hello RocketMQ " +
                    i).getBytes(RemotingHelper.DEFAULT_CHARSET) /* Message body */
            );
            //Call send message to deliver message to one of brokers.
 

            SendResult sendResult = producer.send(msg);
            System.out.printf("%s%n", sendResult);
        }
        //Shut down once the producer instance is not longer in use.
        producer.shutdown();
    }
}

可靠異步發送

通常用於對發送消息響應時間要求更高/更快的場景

public class AsyncProducer {
    public static
 
 void main(
        String[] args) throws MQClientException, InterruptedException, UnsupportedEncodingException {
        DefaultMQProducer producer = new DefaultMQProducer("Jodie_Daily_test");
        producer.start();
        producer.setRetryTimesWhenSendAsyncFailed(0);

        for (int i = 0; i < 10000000; i++) {
            try {
                final int index = i;
                Message msg = new Message("Jodie_topic_1023",
                    "TagA",
                    "OrderID188",
                    "Hello world".getBytes(RemotingHelper.DEFAULT_CHARSET));
                    //重點在這裏 異步發送回調
                producer.send(msg, new SendCallback() {
                    @Override
                    public void onSuccess(SendResult sendResult) {
                        System.out.printf("%-10d OK %s %n", index, sendResult.getMsgId());
                    }

                    @Override
                    public void onException(Throwable e) {
                        System.out.printf("%-10d Exception %s %n", index, e);
                        e.printStackTrace();
                    }
                });
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        producer.shutdown();
    }
}

單向發送

適用於某些耗時非常短，但對可靠性要求並不高的場景，例如日誌收集。

只發送消息，不等待服務器響應，只發送請求不等待應答。此方式發送消息的過程耗時非常短，一般在微秒級別。

public class OnewayProducer {
    public static void main(String[] args) throws Exception{
        DefaultMQProducer producer = new DefaultMQProducer("Test");
        producer.start();
        for (int i = 0; i < 100; i++) {
            //Create a message instance, specifying topic, tag and message body.
            Message msg = new Message("TopicTest" /* Topic */,
                "TagA" /* Tag */,
                ("Hello RocketMQ " +
                    i).getBytes(RemotingHelper.DEFAULT_CHARSET) /* Message body */
            );
            //Call send message to deliver message to one of brokers.
            producer.sendOneway(msg);

        }
        //Shut down once the producer instance is not longer in use.
        producer.shutdown();
    }
}

rocketmq簡單消息發送