{% include toc %}
maven:
<dependency> <groupId>org.apache.rocketmq</groupId> <artifactId>rocketmq-client</artifactId> <version>4.3.0</version> </dependency>
gradle:
compile 'org.apache.rocketmq:rocketmq-client:4.3.0'
Reliable synchronous transmission is used in extensive scenes, such as important notification messages, SMS notification, SMS marketing system, etc..
public class SyncProducer { public static void main(String[] args) throws Exception { //Instantiate with a producer group name. DefaultMQProducer producer = new DefaultMQProducer("please_rename_unique_group_name"); // Specify name server addresses. producer.setNamesrvAddr("localhost:9876"); //Launch the instance. 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. SendResult sendResult = producer.send(msg); System.out.printf("%s%n", sendResult); } //Shut down once the producer instance is not longer in use. producer.shutdown(); } }
Asynchronous transmission is generally used in response time sensitive business scenarios.
public class AsyncProducer { public static void main(String[] args) throws Exception { //Instantiate with a producer group name. DefaultMQProducer producer = new DefaultMQProducer("please_rename_unique_group_name"); // Specify name server addresses. producer.setNamesrvAddr("localhost:9876"); //Launch the instance. producer.start(); producer.setRetryTimesWhenSendAsyncFailed(0); int messageCount = 100; final CountDownLatch countDownLatch = new CountDownLatch(messageCount); for (int i = 0; i < messageCount; i++) { try { final int index = i; Message msg = new Message("Jodie_topic_1023", "TagA", "OrderID188", "Hello world".getBytes(RemotingHelper.DEFAULT_CHARSET)); producer.send(msg, new SendCallback() { @Override public void onSuccess(SendResult sendResult) { countDownLatch.countDown(); System.out.printf("%-10d OK %s %n", index, sendResult.getMsgId()); } @Override public void onException(Throwable e) { countDownLatch.countDown(); System.out.printf("%-10d Exception %s %n", index, e); e.printStackTrace(); } }); } catch (Exception e) { e.printStackTrace(); } } countDownLatch.await(5, TimeUnit.SECONDS); producer.shutdown(); } }
One-way transmission is used for cases requiring moderate reliability, such as log collection.
public class OnewayProducer { public static void main(String[] args) throws Exception{ //Instantiate with a producer group name. DefaultMQProducer producer = new DefaultMQProducer("please_rename_unique_group_name"); // Specify name server addresses. producer.setNamesrvAddr("localhost:9876"); //Launch the instance. 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); } //Wait for sending to complete Thread.sleep(5000); producer.shutdown(); } }
public class Consumer { public static void main(String[] args) throws InterruptedException, MQClientException { // Instantiate with specified consumer group name. DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("please_rename_unique_group_name"); // Specify name server addresses. consumer.setNamesrvAddr("localhost:9876"); // Subscribe one more more topics to consume. consumer.subscribe("TopicTest", "*"); // Register callback to execute on arrival of messages fetched from brokers. consumer.registerMessageListener(new MessageListenerConcurrently() { @Override public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) { System.out.printf("%s Receive New Messages: %s %n", Thread.currentThread().getName(), msgs); return ConsumeConcurrentlyStatus.CONSUME_SUCCESS; } }); //Launch the consumer instance. consumer.start(); System.out.printf("Consumer Started.%n"); } }
Alternatively, you could get more examples from: https://github.com/apache/rocketmq/tree/master/example