RocketMQ / rocketmq-example / src / main / java / com / alibaba / rocketmq / example / simple /

https://github.com/alibaba/RocketMQ/blob/develop/rocketmq-example/src/main/java/com/alibaba/rocketmq/example/simple/PushConsumer.java

/**
* Copyright (C) 2010-2013 Alibaba Group Holding Limited
*
* Licensed 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 com.alibaba.rocketmq.example.simple;

import java.util.List;

import com.alibaba.rocketmq.client.consumer.DefaultMQPushConsumer;
import com.alibaba.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import com.alibaba.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import com.alibaba.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import com.alibaba.rocketmq.client.exception.MQClientException;
import com.alibaba.rocketmq.common.consumer.ConsumeFromWhere;
import com.alibaba.rocketmq.common.message.MessageExt;

public class PushConsumer {

/**
* 当前例子是PushConsumer用法，使用方式给用户感觉是消息从RocketMQ服务器推到了应用客户端。<br>
* 但是实际PushConsumer内部是使用长轮询Pull方式从Broker拉消息，然后再回调用户Listener方法<br>
*/
public static void main(String[] args) throws InterruptedException, MQClientException {
/**
* 一个应用创建一个Consumer，由应用来维护此对象，可以设置为全局对象或者单例<br>
* 注意：ConsumerGroupName需要由应用来保证唯一
*/
DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("CID_001");
// consumer.setNamesrvAddr("10.235.169.72:9876");
// consumer.setNamesrvAddr("127.0.0.1:9876");

/**
* 订阅指定topic下tags分别等于TagA或TagC或TagD
*/
consumer.subscribe("TopicTest1", "TagA || TagC || TagD");
/**
* 订阅指定topic下所有消息<br>
* 注意：一个consumer对象可以订阅多个topic
*/
consumer.subscribe("TopicTest2", "*");
consumer.subscribe("TopicTest3", "*");

/**
* 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<br>
* 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.registerMessageListener(new MessageListenerConcurrently() {

/**
* 默认msgs里只有一条消息，可以通过设置consumeMessageBatchMaxSize参数来批量接收消息
*/
@Override
public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs,
ConsumeConcurrentlyContext context) {
System.out.println(Thread.currentThread().getName() + " Receive New Messages: " + msgs);

MessageExt msg = msgs.get(0);
if (msg.getTopic().equals("TopicTest1")) {
// 执行TopicTest1的消费逻辑
if (msg.getTags() != null && msg.getTags().equals("TagA")) {
// 执行TagA的消费
}
else if (msg.getTags() != null && msg.getTags().equals("TagC")) {
// 执行TagC的消费
}
else if (msg.getTags() != null && msg.getTags().equals("TagD")) {
// 执行TagD的消费
}
}
else if (msg.getTopic().equals("TopicTest2")) {
// 执行TopicTest2的消费逻辑
}

return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
}
});

/**
* Consumer对象在使用之前必须要调用start初始化，初始化一次即可<br>
*/
consumer.start();

System.out.println("Consumer Started.");
}
}