java RocketMQ快速入门基础知识

<dependency>
<groupId>org.apache.rocketmq</groupId>
<artifactId>rocketmq-client</artifactId>
<version>4.1.0-incubating</version>
</dependency>

DefaultMQProducer producer = new DefaultMQProducer("producer_demo");
//指定NameServer地址
producer.setNamesrvAddr("192.168.116.115:9876;192.168.116.116:9876"); //修改为自己的
/**
* Producer对象在使用之前必须要调用start初始化，初始化一次即可
* 注意：切记不可以在每次发送消息时，都调用start方法
*/
producer.start();

for (int i = 0; i < 997892; i++) {
try {
//构建消息
Message msg = new Message("TopicTest" /* Topic */,
"TagA" /* Tag */,
("测试RocketMQ" + i).getBytes(RemotingHelper.DEFAULT_CHARSET)
);
//发送同步消息
SendResult sendResult = producer.send(msg);
System.out.printf("%s%n", sendResult);
} catch (Exception e) {
e.printStackTrace();
Thread.sleep(1000);
}
}
producer.shutdown();

/**
* Consumer Group,非常重要的概念，后续会慢慢补充
*/
DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("consumer_demo");
//指定NameServer地址，多个地址以 ; 隔开
consumer.setNamesrvAddr("192.168.116.115:9876;192.168.116.116:9876"); //修改为自己的
/**
* 设置Consumer第一次启动是从队列头部开始消费还是队列尾部开始消费
* 如果非第一次启动，那么按照上次消费的位置继续消费
*/
consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);
consumer.subscribe("TopicTest", "*");
consumer.registerMessageListener(new MessageListenerConcurrently() {
@Override
public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs,
ConsumeConcurrentlyContext context) {
try {
for(MessageExt msg:msgs){
String msgbody = new String(msg.getBody(), "utf-8");
System.out.println(" MessageBody: "+ msgbody);//输出消息内容
}
} catch (Exception e) {
e.printStackTrace();
return ConsumeConcurrentlyStatus.RECONSUME_LATER; //稍后再试
}
return ConsumeConcurrentlyStatus.CONSUME_SUCCESS; //消费成功
}
});
consumer.start();
System.out.printf("Consumer Started.%n");

mvn clean package -Dmaven.test.skip=true
java -jar target/rocketmq-console-ng-1.0.0.jar