[Java知识库]SpringBoot集成RocketMQ实现分布式事务

基本概念

RocketMQ 事务消息（Transactional Message）是指应用本地事务和发送消息操作可以被定义到全局事务中，要么同时成功，要么同时失败。RocketMQ 的事务消息提供类似 X/Open XA 的分布事务功能，通过事务消息能达到分布式事务的最终一致?

执行流程

?

(1) 发送方向 MQ 服务端发送消息。
(2) MQ Server 将消息持久化成功之后，向发送方 ACK 确认消息已经发送成功，此时消息为半消息。
(3) 发送方开始执行本地事务逻辑。
(4) 发送方根据本地事务执行结果向 MQ Server 提交二次确认（Commit 或是 Rollback），MQ Server 收到Commit 状态则将半消息标记为可投递，订阅方最终将收到该消息；MQ Server 收到 Rollback 状态则删除半消息，订阅方将不会接受该消息。
(5) 在断网或者是应用重启的特殊情况下，上述步骤4提交的二次确认最终未到达 MQ Server，经过固定时间后MQ Server 将对该消息发起消息回查。
(6) 发送方收到消息回查后，需要检查对应消息的本地事务执行的最终结果。
(7) 发送方根据检查得到的本地事务的最终状态再次提交二次确认，MQ Server 仍按照步骤4对半消息进行操作

项目实例

pom文件内容

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>rocketmq</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>rocketmq</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.rocketmq</groupId>
            <artifactId>rocketmq-spring-boot-starter</artifactId>
            <version>2.2.0</version>
        </dependency>

        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.5.8</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

application.yml

server:
  port: 8088

rocketmq:
  name-server: 127.0.0.1:9876
  access-channel: LOCAL
  producer:
    group: deer_message_push
    send-message-timeout: 3000
    compress-message-body-threshold: 4096
    max-message-size: 2048000
    retry-times-when-send-failed: 2
    retry-next-server: true

消息生产者工具类

package com.example;
import cn.hutool.core.util.IdUtil;
import org.apache.rocketmq.client.producer.SendCallback;
import org.apache.rocketmq.client.producer.SendResult;
import org.apache.rocketmq.client.producer.SendStatus;
import org.apache.rocketmq.client.producer.TransactionSendResult;
import org.apache.rocketmq.spring.core.RocketMQTemplate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Component;

import java.io.Serializable;

/**
 * @Author 何志鹏
 * @Date 2022/8/30 11:44
 * @Version 1.0
 */
@Component
public class RocketmqProducer {

    private final Logger logger = LoggerFactory.getLogger(RocketmqProducer.class);


    @Autowired
    private RocketMQTemplate rocketMQTemplate;


    /**
     * MQ半消息
     *
     * @param topic target topic
     * @param tag   topic's tag
     * @param msg   message
     * @return send status
     */
    public <T extends Serializable> SendStatus txSend(T msg, String topic, String tag) {
        String destination = String.format("%s:%s", topic, tag);

        Message<T> message = MessageBuilder.withPayload(msg)
                .setHeader("KEYS", IdUtil.simpleUUID())
                .setHeader("DESTINATION", destination)
                .build();

        TransactionSendResult result =
                rocketMQTemplate.sendMessageInTransaction(destination, message, msg);

        //发送状态
        String sendStatus = result.getSendStatus().name();
        // 本地事务执行状态
        String localTxState = result.getLocalTransactionState().name();
        logger.info("send tx message sendStatus:{},localTXState:{}",sendStatus,localTxState);
        return result.getSendStatus();
    }

    /**
     * 同步消息
     *
     * @param msg
     * @param topic
     * @param tag
     * @param <T>
     * @return
     */
    public <T extends Serializable> SendStatus syncSend(T msg, String topic, String tag) {
        String destination = String.format("%s:%s", topic, tag);

        Message<T> message = MessageBuilder.withPayload(msg)
                .setHeader("KEYS", IdUtil.simpleUUID())
                .setHeader("DESTINATION", destination)
                .build();
        return rocketMQTemplate.syncSend(destination, message).getSendStatus();
    }

    /**
     * 异步消息
     *
     * @param msg
     * @param topic
     * @param tag
     * @param <T>
     * @return
     */
    public <T extends Serializable> void asyncSend(T msg, String topic, String tag) {
        String destination = String.format("%s:%s", topic, tag);

        Message<T> message = MessageBuilder.withPayload(msg)
                .setHeader("KEYS", IdUtil.simpleUUID())
                .setHeader("DESTINATION", destination)
                .build();
        rocketMQTemplate.asyncSend(destination, message, new SendCallback() {
            @Override
            public void onSuccess(SendResult sendResult) {
                System.out.println("============================发送成功=================================");
            }

            @Override
            public void onException(Throwable e) {
                System.out.println("============================发送失败================================="+e.getMessage());
            }
        });
    }
}

创建user实体类

package com.example;

import java.io.Serializable;

/**
 * @Author 何志鹏
 * @Date 2022/8/30 17:05
 * @Version 1.0
 */
public class User implements Serializable{

    private static final long serialVersionUID = 4247558661107952933L;

    private Integer id;
    private String name;
    private int age;


    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

生产者测试类

package com.example;

import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
class RocketmqApplicationTests {


    @Autowired
    private RocketmqProducer rocketmqProducer;


    @Test
    void contextLoads() {

        User user = new User();
        user.setId(1);
        user.setName("何志鹏555555555555555555555");
        user.setAge(18);
        rocketmqProducer.txSend(user, "topic1", "11111");
        System.out.println("==========================开始发送消息=========================================");
    }

}

消费者

package com.example;

import org.apache.rocketmq.spring.annotation.RocketMQMessageListener;
import org.apache.rocketmq.spring.core.RocketMQListener;
import org.springframework.stereotype.Component;

/**
 * @Author 何志鹏
 * @Date 2022/8/30 14:16
 * @Version 1.0
 */
@Component
@RocketMQMessageListener(consumerGroup = "deer_message_push", topic = "topic1")
public class RocketMQConsumer  implements RocketMQListener {


    @Override
    public void onMessage(Object message) {
        System.out.println("收到的消息为 ================================================: " + message);
    }
}

自定义一个RocketmqTransactionListener注解? 这边为了方便定义哪些消息需要实现事务? 如下：

package com.example;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface RocketmqTransactionListener {
    String topic();

    String selectorExpression();
}

事务监听实现

package com.example;

import org.apache.rocketmq.spring.annotation.RocketMQTransactionListener;
import org.apache.rocketmq.spring.core.RocketMQLocalTransactionListener;
import org.apache.rocketmq.spring.core.RocketMQLocalTransactionState;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.messaging.Message;
import org.springframework.stereotype.Component;

import java.util.concurrent.ConcurrentHashMap;
import java.util.stream.Collectors;
import java.util.stream.Stream;

@Component
@RocketMQTransactionListener(corePoolSize = 2, maximumPoolSize = 10)
public class RocketmqTransactionListenerAdapter implements RocketMQLocalTransactionListener, InitializingBean {
    private final Logger logger = LoggerFactory.getLogger(RocketmqTransactionListenerAdapter.class);
    private final ApplicationContext applicationContext;
    private final ConcurrentHashMap<String, RocketMQLocalTransactionListener> listeners;

    public RocketmqTransactionListenerAdapter(ApplicationContext applicationContext) {
        this.applicationContext = applicationContext;
        this.listeners = new ConcurrentHashMap<>();
    }

    @Override
    public void afterPropertiesSet() {
        applicationContext.getBeansWithAnnotation(RocketmqTransactionListener.class)
                .values()
                .stream()
                .filter(m -> RocketMQLocalTransactionListener.class.isAssignableFrom(m.getClass()))
                .collect(Collectors.toList())
                .forEach(listener -> {
                    RocketmqTransactionListener annotation =
                            listener.getClass().getAnnotation(RocketmqTransactionListener.class);

                    Stream.of(annotation.selectorExpression()
                            .split("\\|\\|"))
                            .forEach(tag -> {
                                String destination = String.format("%s:%s", annotation.topic(), tag);
                                listeners.put(destination, (RocketMQLocalTransactionListener) listener);
                            });
                });
    }

    @Override
    public RocketMQLocalTransactionState executeLocalTransaction(Message msg, Object arg) {
        String destination = getDestination(msg);
        if (!listeners.containsKey(destination)) {
            logger.info("----------------------------------------------------");
            logger.warn("{} transaction message is not supported", destination);
            return RocketMQLocalTransactionState.ROLLBACK;
        } else {
            RocketMQLocalTransactionListener listener = listeners.get(destination);
            return listener.executeLocalTransaction(msg, arg);
        }
    }

    @Override
    public RocketMQLocalTransactionState checkLocalTransaction(Message msg) {
        String destination = getDestination(msg);
        if (!listeners.containsKey(destination)) {
            logger.info("----------------------------------------------------");
            logger.warn("{} transaction message is not supported", destination);
            return RocketMQLocalTransactionState.ROLLBACK;
        } else {
            RocketMQLocalTransactionListener listener = listeners.get(destination);
            return listener.checkLocalTransaction(msg);
        }
    }

    private String getDestination(Message msg) {
        String topic = msg.getHeaders().get("rocketmq_TOPIC", String.class);
        String tags = msg.getHeaders().get("rocketmq_TAGS", String.class);
        return String.format("%s:%s", topic, tags);
    }


}

说明：
定义本地事务处理类，实现RocketMQLocalTransactionListener接口，以及加上@RocketMQTransactionListener注解，这个类似方法的调用是异步的；
executeLocalTransaction方法：当我们处理完业务后，可以根据业务处理情况，返回事务执行状态，有rollback, commit or unknown三种，分别是回滚事务，提交事务和未知；根据事务消息执行流程，如果返回rollback，则直接丢弃消息；如果是返回commit，则消费消息；如果是unknow，则继续等待，然后调用checkLocalTransaction方法，最多重试15次，超过了默认丢弃此消息；
checkLocalTransaction方法：是当MQ Server未得到MQ发送方应答，或者超时的情况，或者应答是unknown的情况，调用此方法进行检查确认，返回值和上面的方法一样；
?

自定义生产者事务监听类

package com.example;

import org.apache.rocketmq.spring.core.RocketMQLocalTransactionListener;
import org.apache.rocketmq.spring.core.RocketMQLocalTransactionState;
import org.springframework.messaging.Message;
import org.springframework.stereotype.Service;

/**
 * @Author 何志鹏
 * @Date 2022/8/30 16:56
 * @Version 1.0
 */
@Service
@RocketmqTransactionListener(topic = "topic1", selectorExpression = "11111")
public class ProducerListener implements RocketMQLocalTransactionListener {





    @Override
    public RocketMQLocalTransactionState executeLocalTransaction(Message msg, Object arg) {
        try {
            //todo 数据库相关逻辑  报错事务回滚 否则事务提交
            int count = 1;
            System.err.println("==================================开始执行事务===============================");
            return count > 0 ? RocketMQLocalTransactionState.COMMIT : RocketMQLocalTransactionState.ROLLBACK;
        } catch (Exception e) {
            System.err.println("=====================================事务执行失败============================================");
            return RocketMQLocalTransactionState.ROLLBACK;
        }
    }

    @Override
    public RocketMQLocalTransactionState checkLocalTransaction(Message msg) {
        try {
            //todo 数据库相关逻辑  报错事务回滚 否则事务提交
            boolean flag = true;
            return flag ? RocketMQLocalTransactionState.COMMIT : RocketMQLocalTransactionState.ROLLBACK;
        } catch (Exception e) {
            System.err.println("=====================================事务执行失败222222============================================");
            return RocketMQLocalTransactionState.ROLLBACK;
        }
    }
}

启动测试类RocketmqApplicationTests测试

当执行程序没有异常的情况下 ?可以看出，执行成功后，消息执行成功返回的结果为SEND_OK，本地事务执行的状态为COMMIT_MESSAGE

回滚测试

仿造异常情况下的程序? 如改动以下程序即可

重启项目进行测试? 打印日志如下：

?从执行的结果可以看出，消息执行成功返回的结果为SEND_OK，本地事务执行的状态为:ROLLBACK_MESSAGE，直接丢弃消息，所以消费端无法消费此消息? 本地事务的状态分别为提交状态、回滚状态、未知状态? 当生产者回调操作执行的结果为本地事务状态。其会发送给TC，而TC会在发送给TM，TM会根据TC发送过来的本地事务状态来决定全局事务确认指令 状态如下：

TransactionStatus.CommitTransaction: 提交事务，它允许消费者消费此消息。
TransactionStatus.RollbackTransaction: 回滚事务，它代表该消息将被删除，不允许被消费。
TransactionStatus.Unknown: 未知状态，它代表需要检查消息队列来确定状态

最后附上项目源码

rocketmq: 测试rocketmq事务实现

?

?

?