RocketMQ中文文档

主要是从官方文档入手，开始学习rocketmq。对RocketMQ 官方文档做翻译吧。

Qucik Start(快速开始)

This quick start guide is a detailed instruction of setting up RocketMQ messaging system on your local machine to send and receive messages.

本章节主要是详细介绍如何在本地计算机上设置RocketMQ消息系统以便于发送和接受消息。

Prerequisite(前提条件)

The following softwares are assumed installed:

1. 64bit OS, Linux/Unix/Mac is recommended;
2. 64bit JDK 1.8+;
3. Maven 3.2.x;
4. Git;
5. 4g+ free disk for Broker server

假设已经安装了一下软件：

1. 推荐 64bit OS，Linux/Unix/Mac 系统

2. 64bit JDK 1.8+

3. Maven 3.2.x

4. Git

5. 有4G+ 空闲磁盘 用于安装Broker 服务器

Download & Build from Release(下载构建)

Click here to download the 4.4.0 source release. Also you could download a binary release from here.

Now execute the following commands to unpack 4.4.0 source release and build the binary artifact.

点击here 下载4.4.0 版本的发行版源代码，你也可以点击 here. 下载二进制发行版。

现在执行以下命令来解压 4.4.0 源代码并构建：

$ unzip rocketmq-all-4.4.0-source-release.zip
$ cd rocketmq-all-4.4.0/
$ mvn -Prelease-all -DskipTests clean install -U
$ cd distribution/target/apache-rocketmq

Start Name Server(启动Name Server 服务)

$ nohup sh bin/mqnamesrv &
$ tail -f ~/logs/rocketmqlogs/namesrv.log
# The Name Server boot success...

注意rocketmq 很吃内存，执行 nohup sh bin/mqnamesrv & 的时候，可能会启动不起来，可以查看log，我就是没启动起来，一查log 才发现，服务器的内存不够啊，难受了啊。最后只能在自己电脑上装一个。

Start Broker(启动Broker)

$ nohup sh bin/mqbroker -n localhost:9876 &
$ tail -f ~/logs/rocketmqlogs/broker.log 
#  The broker[%s, 172.30.30.233:10911] boot success...

Send & Receive Messages(发送和接收消息)

Before sending/receiving messages, we need to tell clients the location of name servers. RocketMQ provides multiple ways to achieve this. For simplicity, we use environment variable NAMESRV_ADDR

在发送/接收消息之前，我们需要告诉客户端服务器的位置。RocketMQ提供了多种方式实现这一点。为了简单起见，我们使用环境变量：NAMEESRV_ADDR

$ export NAMESRV_ADDR=localhost:9876
$ sh bin/tools.sh org.apache.rocketmq.example.quickstart.Producer
#  SendResult [sendStatus=SEND_OK, msgId= ...

$ sh bin/tools.sh org.apache.rocketmq.example.quickstart.Consumer
#  ConsumeMessageThread_%d Receive New Messages: [MessageExt...

Shutdown Servers(关闭服务)

$ sh bin/mqshutdown broker
The mqbroker(36695) is running...
Send shutdown request to mqbroker(36695) OK

$ sh bin/mqshutdown namesrv
The mqnamesrv(36664) is running...
Send shutdown request to mqnamesrv(36664) OK

Simple Example(简单例子)

• Use RocketMQ to send messages in three ways: reliable synchronous, reliable asynchronous, and one-way transmission.
• Use RocketMQ to consume messages

• 通过三种方式来使用RocketMQ发送消息：可靠的同步发送、可靠的异步发送和单向传输；
• 使用 Rocket 进行消费。

1. Add Dependency (添加依赖)

• maven 方式：

  <dependency>
  	<groupId>org.apache.rocketmqgroupId>
  	<artifactId>rocketmq-clientartifactId>
  	<version>4.3.0version>
  dependency>
  

• gradle 方式

  compile 'org.apache.rocketmq:rocketmq-client:4.3.0'
  

2.1 Send Messages Synchronously(同步发送消息)

Reliable synchronous transmission is used in extensive scenes, such as important notification messages, SMS notification, SMS marketing system, etc…

可靠的同步传输广泛应用于重要场景，如：重要信息通知，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. Send Messages Asynchronously(异步发送消息)

Asynchronous transmission is generally used in response time sensitive business scenarios.

异步传输通常用于相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. Send Messages in One-way Mode(单向传输)

One-way transmission is used for cases requiring moderate reliability, such as log collection.

单向传输用于需要中等可靠性的情况，例如日志收集。

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. Consume Messages(消费)

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. Find More

Alternatively, you could get more examples from: https://github.com/apache/rocketmq/tree/master/example

Order Message(订阅信息)

RocketMQ provides ordered messages using FIFO order.

The following example demonstrates sending/recieving of globally and partitionally ordered message.

RocketMQ 通过 FIFO 顺序提供有序消息.

以下示例演示发送/接收全局和分区有序消息：

Send message sample code(发送消息示例代码)

public class OrderedProducer {
    public static void main(String[] args) throws Exception {
        // Instantiate with a producer group name.
        MQProducer producer = new DefaultMQProducer("example_group_name");
        // Launch the instance.
        producer.start();
        String[] tags = new String[] {"TagA", "TagB", "TagC", "TagD", "TagE"};
        for (int i = 0; i < 100; i++) {
            int orderId = i % 10;
            // Create a message instance, specifying topic, tag and message body.
            Message msg = new Message("TopicTestjjj", tags[i % tags.length], "KEY" + i,
                    ("Hello RocketMQ " + i).getBytes(RemotingHelper.DEFAULT_CHARSET));
            SendResult sendResult = producer.send(msg, new MessageQueueSelector() {
            @Override
            public MessageQueue select(List<MessageQueue> mqs, Message msg, Object arg) {
                Integer id = (Integer) arg;
                int index = id % mqs.size();
                return mqs.get(index);
            }
            }, orderId);
            System.out.printf("%s%n", sendResult);
        }
        // server shutdown
        producer.shutdown();
    }
}

Subscription message sample code(订阅消息简单示例代码)

public class OrderedConsumer {
    public static void main(String[] args) throws Exception {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("example_group_name");
        consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);
        consumer.subscribe("TopicTest", "TagA || TagC || TagD");
        consumer.registerMessageListener(new MessageListenerOrderly() {
            AtomicLong consumeTimes = new AtomicLong(0);
            @Override
            public ConsumeOrderlyStatus consumeMessage(List<MessageExt> msgs,
                                                       ConsumeOrderlyContext context) {
                context.setAutoCommit(false);
                System.out.printf(Thread.currentThread().getName() + " Receive New Messages: " + msgs + "%n");
                this.consumeTimes.incrementAndGet();
                if ((this.consumeTimes.get() % 2) == 0) {
                    return ConsumeOrderlyStatus.SUCCESS;
                } else if ((this.consumeTimes.get() % 3) == 0) {
                    return ConsumeOrderlyStatus.ROLLBACK;
                } else if ((this.consumeTimes.get() % 4) == 0) {
                    return ConsumeOrderlyStatus.COMMIT;
                } else if ((this.consumeTimes.get() % 5) == 0) {
                    context.setSuspendCurrentQueueTimeMillis(3000);
                    return ConsumeOrderlyStatus.SUSPEND_CURRENT_QUEUE_A_MOMENT;
                }
                return ConsumeOrderlyStatus.SUCCESS;

            }
        });

        consumer.start();

        System.out.printf("Consumer Started.%n");
    }
}

Broadcasting(广播)

What is broadcasting

Broadcasting is sending a message to all subscribers of a topic. If you want all subscribers receive messages about a topic, broadcasting is a good choice.

广播是向所有用户发送消息。 如果您希望所有订阅者都能收到有关某个主题的消息，则广播是一个不错的选择。

Producer Example

public class BroadcastProducer {
    public static void main(String[] args) throws Exception {
        DefaultMQProducer producer = new DefaultMQProducer("ProducerGroupName");
        producer.start();

        for (int i = 0; i < 100; i++){
            Message msg = new Message("TopicTest",
                "TagA",
                "OrderID188",
                "Hello world".getBytes(RemotingHelper.DEFAULT_CHARSET));
            SendResult sendResult = producer.send(msg);
            System.out.printf("%s%n", sendResult);
        }
        producer.shutdown();
    }
}

Consumer example

public class BroadcastConsumer {
    public static void main(String[] args) throws Exception {
        DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("example_group_name");

        consumer.setConsumeFromWhere(ConsumeFromWhere.CONSUME_FROM_FIRST_OFFSET);

        //set to broadcast mode
        consumer.setMessageModel(MessageModel.BROADCASTING);

        consumer.subscribe("TopicTest", "TagA || TagC || TagD");

        consumer.registerMessageListener(new MessageListenerConcurrently() {

            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs,
                ConsumeConcurrentlyContext context) {
                System.out.printf(Thread.currentThread().getName() + " Receive New Messages: " + msgs + "%n");
                return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
            }
        });

        consumer.start();
        System.out.printf("Broadcast Consumer Started.%n");
    }
}

Schedule example(定时)

What is Schedule message

Scheduled messages differ from normal messages in that they won’t be delivered until a provided time later.

定时消息与正常消息的不同之处在于，它是在指定的时间后执行。

Start consumer to wait for incoming subscribed messages(启动消费者等待传入订阅消息)

import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
 import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
 import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
 import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
 import org.apache.rocketmq.common.message.MessageExt;
 import java.util.List;
    
 public class ScheduledMessageConsumer {
    
     public static void main(String[] args) throws Exception {
         // Instantiate message consumer
         DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("ExampleConsumer");
         // Subscribe topics
         consumer.subscribe("TestTopic", "*");
         // Register message listener
         consumer.registerMessageListener(new MessageListenerConcurrently() {
             @Override
             public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> messages, ConsumeConcurrentlyContext context) {
                 for (MessageExt message : messages) {
                     // Print approximate delay time period
                     System.out.println("Receive message[msgId=" + message.getMsgId() + "] "
                             + (System.currentTimeMillis() - message.getStoreTimestamp()) + "ms later");
                 }
                 return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
             }
         });
         // Launch consumer
         consumer.start();
     }
 }

Send scheduled messages(发送定时消息)

import org.apache.rocketmq.client.producer.DefaultMQProducer;
 import org.apache.rocketmq.common.message.Message;
    
 public class ScheduledMessageProducer {
    
     public static void main(String[] args) throws Exception {
         // Instantiate a producer to send scheduled messages
         DefaultMQProducer producer = new DefaultMQProducer("ExampleProducerGroup");
         // Launch producer
         producer.start();
         int totalMessagesToSend = 100;
         for (int i = 0; i < totalMessagesToSend; i++) {
             Message message = new Message("TestTopic", ("Hello scheduled message " + i).getBytes());
             // This message will be delivered to consumer 10 seconds later.
             message.setDelayTimeLevel(3);
             // Send the message
             producer.send(message);
         }
    
         // Shutdown producer after use.
         producer.shutdown();
     }
        
 }

Verification(核实)

You should see messages are consumed about 10 seconds later than their storing time.

您应该看到消息比其存储时间晚约10秒钟。

Batch Example(批量)

Why batch？

Sending messages in batch improves performance of delivering small messages.

批量发送消息可提高单次发送消息的性能.

Usage constraints(使用限制)

Messages of the same batch should have: same topic, same waitStoreMsgOK and no schedule support.

Besides, the total size of the messages in one batch should be no more than 1MiB.

相同批次的消息应具有：相同的主题，相同的等待消息处理成功但是不支持定时处理. 此外，一个批量的消息的总大小不要错过1MB.

How to use batch

If you just send messages of no more than 1MiB at a time, it is easy to use batch:

如果您一次只发送不超过1MB的消息，使用批量发送很方便:

String topic = "BatchTest";
List<Message> messages = new ArrayList<>();
messages.add(new Message(topic, "TagA", "OrderID001", "Hello world 0".getBytes()));
messages.add(new Message(topic, "TagA", "OrderID002", "Hello world 1".getBytes()));
messages.add(new Message(topic, "TagA", "OrderID003", "Hello world 2".getBytes()));
try {
    producer.send(messages);
} catch (Exception e) {
    e.printStackTrace();
    //handle the error
}

Split into lists(分割成列表)

The complexity only grow when you send large batch and you may not sure if it exceeds the size limit (1MiB).

At this time, you’d better split the lists:

只有在发送大批量时才会增加复杂性，并且您可能不确定是否超出了大小限制（1MiB）。

目前，你最好分开列表:

public class ListSplitter implements Iterator<List<Message>> {
    private final int SIZE_LIMIT = 1000 * 1000;
    private final List<Message> messages;
    private int currIndex;
    public ListSplitter(List<Message> messages) {
            this.messages = messages;
    }
    @Override public boolean hasNext() {
        return currIndex < messages.size();
    }
    @Override public List<Message> next() {
        int nextIndex = currIndex;
        int totalSize = 0;
        for (; nextIndex < messages.size(); nextIndex++) {
            Message message = messages.get(nextIndex);
            int tmpSize = message.getTopic().length() + message.getBody().length;
            Map<String, String> properties = message.getProperties();
            for (Map.Entry<String, String> entry : properties.entrySet()) {
                tmpSize += entry.getKey().length() + entry.getValue().length();
            }
            tmpSize = tmpSize + 20; //for log overhead
            if (tmpSize > SIZE_LIMIT) {
                //it is unexpected that single message exceeds the SIZE_LIMIT
                //here just let it go, otherwise it will block the splitting process
                if (nextIndex - currIndex == 0) {
                   //if the next sublist has no element, add this one and then break, otherwise just break
                   nextIndex++;  
                }
                break;
            }
            if (tmpSize + totalSize > SIZE_LIMIT) {
                break;
            } else {
                totalSize += tmpSize;
            }
    
        }
        List<Message> subList = messages.subList(currIndex, nextIndex);
        currIndex = nextIndex;
        return subList;
    }
}
//then you could split the large list into small ones:
ListSplitter splitter = new ListSplitter(messages);
while (splitter.hasNext()) {
   try {
       List<Message>  listItem = splitter.next();
       producer.send(listItem);
   } catch (Exception e) {
       e.printStackTrace();
       //handle the error
   }
}

Filter Example(过滤)

In most cases, tag is a simple and useful design to select message you want. For example:

DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("CID_EXAMPLE");
consumer.subscribe("TOPIC", "TAGA || TAGB || TAGC");

The consumer will recieve messages that contains TAGA or TAGB or TAGC. But the limitation is that one message only can have one tag, and this may not work for sophisticated scenarios. In this case, you can use SQL expression to filter out messages.

在大多数情况下，tag是一种简单而有用的设计，用于选择所需的信息。 例如:

DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("CID_EXAMPLE");
consumer.subscribe("TOPIC", "TAGA || TAGB || TAGC");

消费者将收到包含TAGA或TAGB或TAGB的消息. 但限制是一条消息只能有一个标签，而这对于复杂的情况可能无效。 在这种情况下，您可以使用SQL表达式筛选出消息.

Principle(原理)

SQL feature could do some calculation through the properties you put in when sending messages. Under the grammars defined by RocketMQ, you can implement some interesting logic. Here is an example:

SQL功能可以通过您在发送消息时放入的属性进行一些计算。 在RocketMQ定义的语法下，您可以实现一些有趣的逻辑。 这是一个例子:

------------
| message  |
|----------|  a > 5 AND b = 'abc'
| a = 10   |  --------------------> Gotten
| b = 'abc'|
| c = true |
------------
------------
| message  |
|----------|   a > 5 AND b = 'abc'
| a = 1    |  --------------------> Missed
| b = 'abc'|
| c = true |
------------

Grammars(语法)

RocketMQ only defines some basic grammars to support this feature. You could also extend it easily.

1. Numeric comparison, like >, >=, <, <=, BETWEEN, =;
2. Character comparison, like =, <>, IN;
3. IS NULL or IS NOT NULL;
4. Logical AND, OR, NOT;

Constant types are:

1. Numeric, like 123, 3.1415;
2. Character, like ‘abc’, must be made with single quotes;
3. NULL, special constant;
4. Boolean, TRUE or FALSE;

RocketMQ只定义了一些基本的语法来支持这个功能。 你也可以很容易地扩展它.

1. 数字比较, 像 >, >=, <, <=, BETWEEN, =;
2. 字符比较, 像 =, <>, IN;
3. IS NULL 或者 IS NOT NULL;
4. 逻辑运算AND, OR, NOT;

常量类型是:

1. 数字, 像123, 3.1415;
2. 字符串, 像‘abc’,必须使用单引号;
3. NULL, 特殊常数;
4. 布尔常量, TRUE 或FALSE;

Usage constraints(使用限制)

Only push consumer could select messages by SQL92. The interface is:

只有消费者可以通过SQL92选择消息。 示例:

public void subscribe(final String topic, final MessageSelector messageSelector)

Producer example(生产者示例)

You can put properties in message through method putUserProperty when sending.

发送时，您可以通过putUserProperty方法在消息中放置属性.

DefaultMQProducer producer = new DefaultMQProducer("please_rename_unique_group_name");
producer.start();

Message msg = new Message("TopicTest",
    tag,
    ("Hello RocketMQ " + i).getBytes(RemotingHelper.DEFAULT_CHARSET)
);
// Set some properties.
msg.putUserProperty("a", String.valueOf(i));

SendResult sendResult = producer.send(msg);
   
producer.shutdown();

Consumer example(消费者示例)

Use MessageSelector.bySql to select messages through SQL92 when consuming.

消费时，使用Message Selector.by Sql通过SQL92选择消息.

DefaultMQPushConsumer consumer = new DefaultMQPushConsumer("please_rename_unique_group_name_4");

// only subsribe messages have property a, also a >=0 and a <= 3
consumer.subscribe("TopicTest", MessageSelector.bySql("a between 0 and 3");

consumer.registerMessageListener(new MessageListenerConcurrently() {
    @Override
    public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> msgs, ConsumeConcurrentlyContext context) {
        return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
    }
});
consumer.start();

Logappender Example(日志追加)

RocketMQ logappender provides log4j appender, log4j2 appender and logback appender for bussiness to use, below are config examples.

RocketMQ logappender提供log4j appender，log4j2 appender和logback appender供业务使用，下面是配置示例.

log4j

When using log4j properties config file,config as below.(当使用log4j属性配置文件时，config如下.)

log4j.appender.mq=org.apache.rocketmq.logappender.log4j.RocketmqLog4jAppender
log4j.appender.mq.Tag=yourTag
log4j.appender.mq.Topic=yourLogTopic
log4j.appender.mq.ProducerGroup=yourLogGroup
log4j.appender.mq.NameServerAddress=yourRocketmqNameserverAddress
log4j.appender.mq.layout=org.apache.log4j.PatternLayout
log4j.appender.mq.layout.ConversionPattern=%d{yyyy-MM-dd HH:mm:ss} %-4r [%t] (%F:%L) %-5p - %m%n

When using log4j xml config file,config it as this and also add a async appender:(当使用log4j xml配置文件时，将其配置为此，并添加一个异步appender:)

<appender name="mqAppender1" class="org.apache.rocketmq.logappender.log4j.RocketmqLog4jAppender">
    <param name="Tag" value="yourTag" />
    <param name="Topic" value="yourLogTopic" />
    <param name="ProducerGroup" value="yourLogGroup" />
    <param name="NameServerAddress" value="yourRocketmqNameserverAddress"/>
    <layout class="org.apache.log4j.PatternLayout">
        <param name="ConversionPattern" value="%d{yyyy-MM-dd HH:mm:ss}-%p %t %c - %m%n" />
    layout>
appender>

<appender name="mqAsyncAppender1" class="org.apache.log4j.AsyncAppender">
    <param name="BufferSize" value="1024" />
    <param name="Blocking" value="false" />
    <appender-ref ref="mqAppender1"/>
appender>

log4j2

When using log4j2,config as this.If you want noneblock,just config an asyncAppender for ref.(当使用log4j2时，config为这个。如果你想要noneblock，只需要为ref配置一个asyncAppender.)

<RocketMQ name="rocketmqAppender" producerGroup="yourLogGroup" nameServerAddress="yourRocketmqNameserverAddress"
     topic="yourLogTopic" tag="yourTag">
    <PatternLayout pattern="%d [%p] hahahah %c %m%n"/>
RocketMQ>

logback

When using logback,an asyncAppender also needed.(在使用logback时，还需要一个asyncAppender.)

<appender name="mqAppender1" class="org.apache.rocketmq.logappender.logback.RocketmqLogbackAppender">
    <tag>yourTagtag>
    <topic>yourLogTopictopic>
    <producerGroup>yourLogGroupproducerGroup>
    <nameServerAddress>yourRocketmqNameserverAddressnameServerAddress>
    <layout>
        <pattern>%date %p %t - %m%npattern>
    layout>
appender>

<appender name="mqAsyncAppender1" class="ch.qos.logback.classic.AsyncAppender">
    <queueSize>1024queueSize>
    <discardingThreshold>80discardingThreshold>
    <maxFlushTime>2000maxFlushTime>
    <neverBlock>trueneverBlock>
    <appender-ref ref="mqAppender1"/>
appender>

OpenMessaging Example

which includes the establishment of industry guidelines and messaging, streaming specifications to provide a common framework for finance, e-commerce, IoT and big-data area. The design principles are the cloud-oriented, simplicity, flexibility, and language independent in distributed heterogeneous environments. Conformance to these specifications will make it possible to develop a heterogeneous messaging applications across all major platforms and operating systems.

RocketMQ provides a partial implementation of OpenMessaging 0.1.0-alpha, the following examples demonstrate how to access RocketMQ based on OpenMessaging.

OpenMessaging，其中包括建立行业准则和消息传递，流式规范，为金融，电子商务，物联网和大数据领域提供通用框架。 设计原则是分布式异构环境中面向云，简单，灵活和独立于语言的设计原则。 符合这些规范将使在所有主要平台和操作系统上开发异构消息传递应用成为可能。

RocketMQ提供了OpenMessaging 0.1.0-alpha的部分实现，以下示例演示了如何基于OpenMessaging访问RocketMQ。

OMSProducer

The following example shows how to send message to RocketMQ broker in synchronous, asynchronous, or one-way transmissions.

以下示例显示如何以同步，异步或单向传输的方式向RocketMQ代理发送消息.

public class OMSProducer {
    public static void main(String[] args) {
        final MessagingAccessPoint messagingAccessPoint = MessagingAccessPointFactory
            .getMessagingAccessPoint("openmessaging:rocketmq://IP1:9876,IP2:9876/namespace");

        final Producer producer = messagingAccessPoint.createProducer();

        messagingAccessPoint.startup();
        System.out.printf("MessagingAccessPoint startup OK%n");

        producer.startup();
        System.out.printf("Producer startup OK%n");

        {
            Message message = producer.createBytesMessageToTopic("OMS_HELLO_TOPIC", "OMS_HELLO_BODY".getBytes(Charset.forName("UTF-8")));
            SendResult sendResult = producer.send(message);
            System.out.printf("Send sync message OK, msgId: %s%n", sendResult.messageId());
        }

        {
            final Promise<SendResult> result = producer.sendAsync(producer.createBytesMessageToTopic("OMS_HELLO_TOPIC", "OMS_HELLO_BODY".getBytes(Charset.forName("UTF-8"))));
            result.addListener(new PromiseListener<SendResult>() {
                @Override
                public void operationCompleted(Promise<SendResult> promise) {
                    System.out.printf("Send async message OK, msgId: %s%n", promise.get().messageId());
                }

                @Override
                public void operationFailed(Promise<SendResult> promise) {
                    System.out.printf("Send async message Failed, error: %s%n", promise.getThrowable().getMessage());
                }
            });
        }

        {
            producer.sendOneway(producer.createBytesMessageToTopic("OMS_HELLO_TOPIC", "OMS_HELLO_BODY".getBytes(Charset.forName("UTF-8"))));
            System.out.printf("Send oneway message OK%n");
        }

        producer.shutdown();
        messagingAccessPoint.shutdown();
    }
}

OMSPullConsumer

Use OMS PullConsumer to poll messages from a specified queue.

使用OMS PullConsumer轮询来自指定队列的消息.

public class OMSPullConsumer {
    public static void main(String[] args) {
        final MessagingAccessPoint messagingAccessPoint = MessagingAccessPointFactory
            .getMessagingAccessPoint("openmessaging:rocketmq://IP1:9876,IP2:9876/namespace");

        final PullConsumer consumer = messagingAccessPoint.createPullConsumer("OMS_HELLO_TOPIC",
            OMS.newKeyValue().put(NonStandardKeys.CONSUMER_GROUP, "OMS_CONSUMER"));

        messagingAccessPoint.startup();
        System.out.printf("MessagingAccessPoint startup OK%n");
        
        consumer.startup();
        System.out.printf("Consumer startup OK%n");

        Message message = consumer.poll();
        if (message != null) {
            String msgId = message.headers().getString(MessageHeader.MESSAGE_ID);
            System.out.printf("Received one message: %s%n", msgId);
            consumer.ack(msgId);
        }

        consumer.shutdown();
        messagingAccessPoint.shutdown();
    }
}

OMSPushConsumer

Attaches OMS PushConsumer to a specified queue and consumes messages by MessageListener

通过MessageListener将OMS PushConsumer附加到指定的队列并使用消息

public class OMSPushConsumer {
    public static void main(String[] args) {
        final MessagingAccessPoint messagingAccessPoint = MessagingAccessPointFactory
            .getMessagingAccessPoint("openmessaging:rocketmq://IP1:9876,IP2:9876/namespace");

        final PushConsumer consumer = messagingAccessPoint.
            createPushConsumer(OMS.newKeyValue().put(NonStandardKeys.CONSUMER_GROUP, "OMS_CONSUMER"));

        messagingAccessPoint.startup();
        System.out.printf("MessagingAccessPoint startup OK%n");

        Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
            @Override
            public void run() {
                consumer.shutdown();
                messagingAccessPoint.shutdown();
            }
        }));
        
        consumer.attachQueue("OMS_HELLO_TOPIC", new MessageListener() {
            @Override
            public void onMessage(final Message message, final ReceivedMessageContext context) {
                System.out.printf("Received one message: %s%n", message.headers().getString(MessageHeader.MESSAGE_ID));
                context.ack();
            }
        });
        
    }
}

Transaction example(事务)

What is transactional message?

It can be thought of as a two-phase commit message implementation to ensure eventual consistency in distributed system. Transactional message ensures that the execution of local transaction and the sending of message can be performed atomically.

Usage Constraint

(1) Messages of the transactional have no schedule and batch support.
(2) In order to avoid a single message being checked too many times and lead to half queue message accumulation， we limited the number of checks for a single message to 15 times by default, but users can change this limit by change the “transactionCheckMax” parameter in the configuration of the broker， if one message has been checked over “transactionCheckMax” times， broker will discard this message and print an error log at the same time by default. Users can change this behavior by override the “AbstractTransactionCheckListener” class.
(3) A transactional message will be checked after a certain period of time that determined by parameter “transactionTimeout” in the configuration of the broker. And users also can change this limit by set user property “CHECK_IMMUNITY_TIME_IN_SECONDS” when sending transactional message, this parameter takes precedence over the “transactionMsgTimeout” parameter.
(4) A transactional message maybe checked or consumed more than once.
(5) Committed message reput to the user’s target topic may fail. Currently, it depends on the log record. High availability is ensured by the high availability mechanism of RocketMQ itself. If you want to ensure that the transactional message isn’t lost and the transaction integrity is guaranteed, it is recommended to use synchronous double write. mechanism.
(6) Producer IDs of transactional messages cannot be shared with producer IDs of other types of messages. Unlike other types of message, transactional messages allow backward queries. MQ Server query clients by their Producer IDs.

Application

1、 Transactional status

There are three states for transactional message:
(1) TransactionStatus.CommitTransaction: commit transaction，it means that allow consumers to consume this message.
(2) TransactionStatus.RollbackTransaction: rollback transaction，it means that the message will be deleted and not allowed to consume.
(3) TransactionStatus.Unknown: intermediate state，it means that MQ is needed to check back to determine the status.

2、Send transactional message

（1）Create the transactional producer
Use TransactionMQProducer class to create producer client, and specify a unique producerGroup, and you can set up a custom thread pool to process check requests. After executing the local transaction, you need to reply to MQ according to the execution result，and the reply status is described in the above section.

import org.apache.rocketmq.client.consumer.DefaultMQPushConsumer;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyContext;
import org.apache.rocketmq.client.consumer.listener.ConsumeConcurrentlyStatus;
import org.apache.rocketmq.client.consumer.listener.MessageListenerConcurrently;
import org.apache.rocketmq.common.message.MessageExt;
import java.util.List;

public class TransactionProducer {
    public static void main(String[] args) throws MQClientException, InterruptedException {
        TransactionListener transactionListener = new TransactionListenerImpl();
        TransactionMQProducer producer = new TransactionMQProducer("please_rename_unique_group_name");
        ExecutorService executorService = new ThreadPoolExecutor(2, 5, 100, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(2000), new ThreadFactory() {
            @Override
            public Thread newThread(Runnable r) {
                Thread thread = new Thread(r);
                thread.setName("client-transaction-msg-check-thread");
                return thread;
            }
        });

        producer.setExecutorService(executorService);
        producer.setTransactionListener(transactionListener);
        producer.start();

        String[] tags = new String[] {"TagA", "TagB", "TagC", "TagD", "TagE"};
        for (int i = 0; i < 10; i++) {
            try {
                Message msg =
                    new Message("TopicTest1234", tags[i % tags.length], "KEY" + i,
                        ("Hello RocketMQ " + i).getBytes(RemotingHelper.DEFAULT_CHARSET));
                SendResult sendResult = producer.sendMessageInTransaction(msg, null);
                System.out.printf("%s%n", sendResult);

                Thread.sleep(10);
            } catch (MQClientException | UnsupportedEncodingException e) {
                e.printStackTrace();
            }
        }

        for (int i = 0; i < 100000; i++) {
            Thread.sleep(1000);
        }
        producer.shutdown();
    }
}

（2）Implement the TransactionListener interface
The “executeLocalTransaction” method is used to execute local transaction when send half message succeed. It returns one of three transaction status mentioned in the previous section.
The “checkLocalTransaction” method is used to check the local transaction status and respond to MQ check requests. It also returns one of three transaction status mentioned in the previous section.

import ...

public class TransactionListenerImpl implements TransactionListener {
	private AtomicInteger transactionIndex = new AtomicInteger(0);
	private ConcurrentHashMap<String, Integer> localTrans = new ConcurrentHashMap<>();
	@Override
    public LocalTransactionState executeLocalTransaction(Message msg, Object arg) {
        int value = transactionIndex.getAndIncrement();
        int status = value % 3;
        localTrans.put(msg.getTransactionId(), status);
        return LocalTransactionState.UNKNOW;
    }  
    @Override
    public LocalTransactionState checkLocalTransaction(MessageExt msg) {
        Integer status = localTrans.get(msg.getTransactionId());
        if (null != status) {
            switch (status) {
                case 0:
                    return LocalTransactionState.UNKNOW;
                case 1:
                    return LocalTransactionState.COMMIT_MESSAGE;
             	case 2:
                	return LocalTransactionState.ROLLBACK_MESSAGE;
     	 	}
         }
		return LocalTransactionState.COMMIT_MESSAGE;
	}
}