RocketMQ 简单消息示例
RocketMQ 简单消息示例
使用RocketMQ以三种方式发送消息:可靠的同步、可靠的异步和单向传输。
使用RocketMQ消费消息
1. 添加依赖
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'
2.1 发送同步消息
同步传输用于广泛的场景,如重要通知消息、短信通知、短信营销系统等..
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(); } }
2.2 发送异步消息
异步传输通常用于响应时间敏感的业务场景。
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); for (int i = 0; i < 100; i++) { final int index = i; //Create a message instance, specifying topic, tag and message body. Message msg = new Message("TopicTest", "TagA", "OrderID188", "Hello world".getBytes(RemotingHelper.DEFAULT_CHARSET)); 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(); } }); } //Shut down once the producer instance is not longer in use. producer.shutdown(); } }
2.3 以单向模式发送消息
单向传输用于需要中等可靠性的情况,如日志收集。
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); } //Shut down once the producer instance is not longer in use. producer.shutdown(); } }
3. 消费信息
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"); } }
4. 更多例子
你可以从https://github.com/apache/rocketmq/tree/master/example得到更多的例子