RocketMQ新手学习 - API
八、Java API说明:RocketMQ服务端版本为目前最新版:4.7.0Java客户端版本采取的目前最新版:4.7.0pom如下<dependency><groupId>org.apache.rocketmq</groupId><artifactId>rocketmq-client</artifactId><version>
八、Java API
说明:
-
RocketMQ服务端版本为目前最新版:4.7.0
-
Java客户端版本采取的目前最新版:4.7.0
pom如下
<dependency>
<groupId>org.apache.rocketmq</groupId>
<artifactId>rocketmq-client</artifactId>
<version>4.7.0</version>
</dependency>
1、Producer
发消息肯定要必备如下几个条件:
指定生产组名(不能用默认的,会报错)
配置namesrv地址(必须)
指定topic name(必须)
指定tag/key(可选)
验证消息是否发送成功:消息发送完后可以启动消费者进行消费,也可以去管控台上看消息是否存在。
1.1、send(同步)
public class Producer {
public static void main(String[] args) throws Exception {
// 指定生产组名为my-producer
DefaultMQProducer producer = new DefaultMQProducer("my-producer");
// 配置namesrv地址
producer.setNamesrvAddr("124.57.180.156:9876");
// 启动Producer
producer.start();
// 创建消息对象,topic为:myTopic001,消息内容为:hello world
Message msg = new Message("myTopic001", "hello world".getBytes());
// 发送消息到mq,同步的
SendResult result = producer.send(msg);
System.out.println("发送消息成功!result is : " + result);
// 关闭Producer
producer.shutdown();
System.out.println("生产者 shutdown!");
}
}
输出结果:
发送消息成功!result is : SendResult [sendStatus=SEND_OK, msgId=A9FE854140F418B4AAC26F7973910000, offsetMsgId=7B39B49D00002A9F00000000000589BE, messageQueue=MessageQueue [topic=myTopic001, brokerName=broker-a, queueId=0], queueOffset=7]
生产者 shutdown!
1.2、send(批量)
public class ProducerMultiMsg {
public static void main(String[] args) throws Exception {
// 指定生产组名为my-producer
DefaultMQProducer producer = new DefaultMQProducer("my-producer");
// 配置namesrv地址
producer.setNamesrvAddr("124.57.180.156:9876");
// 启动Producer
producer.start();
String topic = "myTopic001";
// 创建消息对象,topic为:myTopic001,消息内容为:hello world1/2/3
Message msg1 = new Message(topic, "hello world1".getBytes());
Message msg2 = new Message(topic, "hello world2".getBytes());
Message msg3 = new Message(topic, "hello world3".getBytes());
// 创建消息对象的集合,用于批量发送
List<Message> msgs = new ArrayList<>();
msgs.add(msg1);
msgs.add(msg2);
msgs.add(msg3);
// 批量发送的api的也是send(),只是他的重载方法支持List<Message>,同样是同步发送。
SendResult result = producer.send(msgs);
System.out.println("发送消息成功!result is : " + result);
// 关闭Producer
producer.shutdown();
System.out.println("生产者 shutdown!");
}
}
输出结果:
发送消息成功!result is : SendResult [sendStatus=SEND_OK, msgId=A9FE854139C418B4AAC26F7D13770000,A9FE854139C418B4AAC26F7D13770001,A9FE854139C418B4AAC26F7D13770002, offsetMsgId=7B39B49D00002A9F0000000000058A62,7B39B49D00002A9F0000000000058B07,7B39B49D00002A9F0000000000058BAC, messageQueue=MessageQueue [topic=myTopic001, brokerName=broker-a, queueId=0], queueOffset=8]
生产者 shutdown!
从结果中可以看到只有一个msgId,所以可以发现虽然是三条消息对象,但是却只发送了一次,大大节省了client与server的开销。
错误情况:
批量发送的topic必须是同一个,如果message对象指定不同的topic,那么批量发送的时候会报错:
Exception in thread "main" org.apache.rocketmq.client.exception.MQClientException: Failed to initiate the MessageBatch
For more information, please visit the url, http://rocketmq.apache.org/docs/faq/
at org.apache.rocketmq.client.producer.DefaultMQProducer.batch(DefaultMQProducer.java:950)
at org.apache.rocketmq.client.producer.DefaultMQProducer.send(DefaultMQProducer.java:898)
at com.chentongwei.mq.rocketmq.ProducerMultiMsg.main(ProducerMultiMsg.java:29)
Caused by: java.lang.UnsupportedOperationException: The topic of the messages in one batch should be the same
at org.apache.rocketmq.common.message.MessageBatch.generateFromList(MessageBatch.java:58)
at org.apache.rocketmq.client.producer.DefaultMQProducer.batch(DefaultMQProducer.java:942)
... 2 more
1.3、sendCallBack(异步)
public class ProducerASync {
public static void main(String[] args) throws Exception {
// 指定生产组名为my-producer
DefaultMQProducer producer = new DefaultMQProducer("my-producer");
// 配置namesrv地址
producer.setNamesrvAddr("124.57.180.156:9876");
// 启动Producer
producer.start();
// 创建消息对象,topic为:myTopic001,消息内容为:hello world async
Message msg = new Message("myTopic001", "hello world async".getBytes());
// 进行异步发送,通过SendCallback接口来得知发送的结果
producer.send(msg, new SendCallback() {
// 发送成功的回调接口
@Override
public void onSuccess(SendResult sendResult) {
System.out.println("发送消息成功!result is : " + sendResult);
}
// 发送失败的回调接口
@Override
public void onException(Throwable throwable) {
throwable.printStackTrace();
System.out.println("发送消息失败!result is : " + throwable.getMessage());
}
});
producer.shutdown();
System.out.println("生产者 shutdown!");
}
}
输出结果:
生产者 shutdown!
java.lang.IllegalStateException: org.apache.rocketmq.remoting.exception.RemotingConnectException: connect to [124.57.180.156:9876] failed
at org.apache.rocketmq.client.impl.factory.MQClientInstance.updateTopicRouteInfoFromNameServer(MQClientInstance.java:681)
at org.apache.rocketmq.client.impl.factory.MQClientInstance.updateTopicRouteInfoFromNameServer(MQClientInstance.java:511)
at org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl.tryToFindTopicPublishInfo(DefaultMQProducerImpl.java:692)
at org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl.sendDefaultImpl(DefaultMQProducerImpl.java:556)
at org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl.access$300(DefaultMQProducerImpl.java:97)
at org.apache.rocketmq.client.impl.producer.DefaultMQProducerImpl$4.run(DefaultMQProducerImpl.java:510)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.rocketmq.remoting.exception.RemotingConnectException: connect to [124.57.180.156:9876] failed
at org.apache.rocketmq.remoting.netty.NettyRemotingClient.getAndCreateNameserverChannel(NettyRemotingClient.java:441)
at org.apache.rocketmq.remoting.netty.NettyRemotingClient.getAndCreateChannel(NettyRemotingClient.java:396)
at org.apache.rocketmq.remoting.netty.NettyRemotingClient.invokeSync(NettyRemotingClient.java:365)
at org.apache.rocketmq.client.impl.MQClientAPIImpl.getTopicRouteInfoFromNameServer(MQClientAPIImpl.java:1371)
at org.apache.rocketmq.client.impl.MQClientAPIImpl.getTopicRouteInfoFromNameServer(MQClientAPIImpl.java:1361)
at org.apache.rocketmq.client.impl.factory.MQClientInstance.updateTopicRouteInfoFromNameServer(MQClientInstance.java:624)
... 10 more
发送消息失败!result is : org.apache.rocketmq.remoting.exception.RemotingConnectException: connect to [124.57.180.156:9876] failed
为啥报错了?很简单,他是异步的,从结果就能看出来,由于是异步的,我还没发送到mq呢,你就先给我shutdown了。肯定不行,所以我们在shutdown前面sleep 1s在看效果
public class ProducerASync {
public static void main(String[] args) throws Exception {
// 指定生产组名为my-producer
DefaultMQProducer producer = new DefaultMQProducer("my-producer");
// 配置namesrv地址
producer.setNamesrvAddr("124.57.180.156:9876");
// 启动Producer
producer.start();
// 创建消息对象,topic为:myTopic001,消息内容为:hello world async
Message msg = new Message("myTopic001", "hello world async".getBytes());
// 进行异步发送,通过SendCallback接口来得知发送的结果
producer.send(msg, new SendCallback() {
// 发送成功的回调接口
@Override
public void onSuccess(SendResult sendResult) {
System.out.println("发送消息成功!result is : " + sendResult);
}
// 发送失败的回调接口
@Override
public void onException(Throwable throwable) {
throwable.printStackTrace();
System.out.println("发送消息失败!result is : " + throwable.getMessage());
}
});
Thread.sleep(1000);
producer.shutdown();
System.out.println("生产者 shutdown!");
}
}
输出结果:
发送消息成功!result is : SendResult [sendStatus=SEND_OK, msgId=A9FE854106E418B4AAC26F8719B20000, offsetMsgId=7B39B49D00002A9F0000000000058CFC, messageQueue=MessageQueue [topic=myTopic001, brokerName=broker-a, queueId=1], queueOffset=2]
生产者 shutdown!
1.4、sendOneway
public class ProducerOneWay {
public static void main(String[] args) throws Exception {
// 指定生产组名为my-producer
DefaultMQProducer producer = new DefaultMQProducer("my-producer");
// 配置namesrv地址
producer.setNamesrvAddr("124.57.180.156:9876");
// 启动Producer
producer.start();
// 创建消息对象,topic为:myTopic001,消息内容为:hello world oneway
Message msg = new Message("myTopic001", "hello world oneway".getBytes());
// 效率最高,因为oneway不关心是否发送成功,我就投递一下我就不管了。所以返回是void
producer.sendOneway(msg);
System.out.println("投递消息成功!,注意这里是投递成功,而不是发送消息成功哦!因为我sendOneway也不知道到底成没成功,我没返回值的。");
producer.shutdown();
System.out.println("生产者 shutdown!");
}
}
输出结果:
投递消息成功!,注意这里是投递成功,而不是发送消息成功哦!因为我sendOneway也不知道到底成没成功,我没返回值的。
生产者 shutdown!
1.5、效率对比
sendOneway > sendCallBack > send批量 > send单条
很容易理解,sendOneway不求结果,我就负责投递,我不管你失败还是成功,相当于中转站,来了我就扔出去,我不进行任何其他处理。所以最快。
而sendCallBack是异步发送肯定比同步的效率高。
send批量和send单条的效率也是分情况的,如果只有1条msg要发,那还搞毛批量,直接send单条完事。
2.* :https://blog.csdn.net/My_SweetXue/article/details/107381324 (放不下,另存一篇文章)
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