org.apache.rocketmq.example.quickstart.Consumer Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.rocketmq.example.quickstart;
import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.client.exception.MQClientException;
import org.apache.rocketmq.common.consumer.ConsumeFromWhere;
/**
* This example shows how to subscribe and consume messages using providing {@link DefaultMQPushConsumer}.
*/
public class Consumer {
public static final String CONSUMER_GROUP = "please_rename_unique_group_name_4";
public static final String DEFAULT_NAMESRVADDR = "127.0.0.1:9876";
public static final String TOPIC = "TopicTest";
public static void main(String[] args) throws MQClientException {
/*
* Instantiate with specified consumer group name.
*/
DefaultMQPushConsumer consumer = new DefaultMQPushConsumer(CONSUMER_GROUP);
/*
* Specify name server addresses.
*
*
* Alternatively, you may specify name server addresses via exporting environmental variable: NAMESRV_ADDR
*
* {@code
* consumer.setNamesrvAddr("name-server1-ip:9876;name-server2-ip:9876");
* }
*
*/
// Uncomment the following line while debugging, namesrvAddr should be set to your local address
// consumer.setNamesrvAddr(DEFAULT_NAMESRVADDR);
/*
* Specify where to start in case the specific consumer group is a brand-new one.
*/
consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);
/*
* Subscribe one more topic to consume.
*/
consumer.subscribe(TOPIC, "*");
/*
* Register callback to execute on arrival of messages fetched from brokers.
*/
consumer.registerMessageListener((MessageListenerConcurrently) (msg, context) -> {
System.out.printf("%s Receive New Messages: %s %n", Thread.currentThread().getName(), msg);
return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
});
/*
* Launch the consumer instance.
*/
consumer.start();
System.out.printf("Consumer Started.%n");
}
}