关于rocketmq:RocketMQ三RocketMQ整合SpringCloud实现分布式事务

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事务音讯的原理


上面来看 RocketMQ 的 事务音讯 是如何来发送“可靠消息”的，只须要以下三步：

  1. 发送半音讯（半音讯不会发送给消费者）
  2. 执行本地事务
  3. 提交音讯


实现 事务音讯 发送后，消费者就能够以失常的形式来生产数据。

RocketMQ 的主动重发机制在绝大多数状况下，都能够保障音讯被正确生产。

如果音讯最终生产失败了，还能够由人工解决进行托底。


下面剖析的是失常状况下的执行流程。上面再来看两种谬误状况：

  1. 事务执行失败时回滚音讯
  2. 服务器无奈得悉音讯状态时，须要被动回查音讯状态

回滚：


音讯回查：

生产者

package demo8;

import org.apache.rocketmq.client.exception.MQClientException;
import org.apache.rocketmq.client.producer.LocalTransactionState;
import org.apache.rocketmq.client.producer.TransactionListener;
import org.apache.rocketmq.client.producer.TransactionMQProducer;
import org.apache.rocketmq.client.producer.TransactionSendResult;
import org.apache.rocketmq.common.message.Message;
import org.apache.rocketmq.common.message.MessageExt;

import java.util.Scanner;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executors;

public class Producer {public static void main(String[] args) throws MQClientException {TransactionMQProducer p = new TransactionMQProducer("producer-demo8");
        p.setNamesrvAddr("192.168.64.151:9876;192.168.64.152:9876");

        p.setExecutorService(Executors.newFixedThreadPool(5));

        p.setTransactionListener(new TransactionListener() {ConcurrentHashMap<String, LocalTransactionState> localTx = new ConcurrentHashMap<>();

            /*
            在这里执行本地事务
             */
            @Override
            public LocalTransactionState executeLocalTransaction(Message message, Object o) {System.out.println("执行本地事务");
                if (Math.random()<0.333) {System.out.println("本地事务执行胜利, 按回车提交事务音讯");
                    new Scanner(System.in).nextLine();

                    localTx.put(message.getTransactionId(), LocalTransactionState.COMMIT_MESSAGE);
                    return LocalTransactionState.COMMIT_MESSAGE;
                } else if (Math.random()<0.666) {System.out.println("本地事务执行失败, 按回车回滚事务音讯");
                    new Scanner(System.in).nextLine();

                    localTx.put(message.getTransactionId(), LocalTransactionState.ROLLBACK_MESSAGE);
                    return LocalTransactionState.ROLLBACK_MESSAGE;
                } else {System.out.println("本地事务执行状况未知, 按回车持续");
                    new Scanner(System.in).nextLine();

                    localTx.put(message.getTransactionId(), LocalTransactionState.UNKNOW);
                    return LocalTransactionState.UNKNOW;
                }
            }

            /*
            回查办法
            检测频率默认 1 分钟，可通过在 broker.conf 文件中设置 transactionCheckInterval 的值来扭转默认值，单位为毫秒。*/
            @Override
            public LocalTransactionState checkLocalTransaction(MessageExt messageExt) {System.out.println("服务器正在回查音讯状态");

                LocalTransactionState s = localTx.get(messageExt.getTransactionId());
                if (s == null || s == LocalTransactionState.UNKNOW) {s = LocalTransactionState.ROLLBACK_MESSAGE;}
                return s;
            }
        });

        p.start();

        String topic = "Topic8";

        while (true) {System.out.print("输出音讯, 用逗号分隔多条音讯:");
            String[] a = new Scanner(System.in).nextLine().split(",");

            for (String s : a) {Message msg = new Message(topic, s.getBytes());
                System.out.println("--------- 发送半音讯 -----------");
                TransactionSendResult r = p.sendMessageInTransaction(msg, null);
                System.out.println("事务音讯发送后果:"+ r.getLocalTransactionState().name());
            }
        }
    }
}

消费者

package demo8;

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;

/*

如果返回 RECONSUME_LATER, 服务器会期待一会再重试发送音讯

音讯属性默认设置 DELAY=6, 等待时间为 2 分钟,

                org/apache/rocketmq/store/config/MessageStoreConfig.java
                this.messageDelayLevel = "1s 5s 10s 30s 1m 2m 3m 4m 5m 6m 7m 8m 9m 10m 20m 30m 1h 2h";


 */
public class Consumer {public static void main(String[] args) throws Exception {DefaultMQPushConsumer c = new DefaultMQPushConsumer("consumer-demo8");
        c.setNamesrvAddr("192.168.64.151:9876:192.168.64.152:9876");

        c.subscribe("Topic8", "*");

        c.registerMessageListener(new MessageListenerConcurrently() {
            @Override
            public ConsumeConcurrentlyStatus consumeMessage(List<MessageExt> list, ConsumeConcurrentlyContext ctx) {for (MessageExt msg : list) {System.out.println(new String(msg.getBody()) + "-" + msg);
                }
                if (Math.random()<0.5) {System.out.println("音讯解决实现");
                    return ConsumeConcurrentlyStatus.CONSUME_SUCCESS;
                } else {System.out.println("音讯解决失败, 要求服务器稍后重试发送音讯");
                    return ConsumeConcurrentlyStatus.RECONSUME_LATER;
                }
            }
        });

        c.start();
        System.out.println("开始生产数据");
    }
}

筹备订单我的项目案例

新建 rocketmq-dtx 工程

新建 Empty Project：

工程命名为 rocketmq-dtx，寄存到任意文件夹下：

导入订单我的项目，无事务版本

下载我的项目代码

  1. 拜访 git 仓库 https://gitee.com/benwang6/seata-samples
  2. 拜访我的项目标签
  3. 下载无事务版

解压到 rocketmq-dtx 目录

压缩文件中的 7 个我的项目目录解压缩到 rocketmq-dtx 目录：

导入我的项目

在 idea 中按两下 shift 键，搜寻 add maven projects，关上 maven 工具：

而后抉择 rocketmq-dtx 工程目录下的 7 个我的项目的 pom.xml 导入：

order 增加事务状态表

Rocketmq 收到事务音讯后，会期待生产者提交或回滚该音讯。如果无奈失去生产者的提交或回滚指令，则会被动向生产者询问音讯状态，称为回查。

在 order 我的项目中，为了让 Rocketmq 能够回查到事务的状态，须要记录事务的状态，所以咱们增加一个事务的状态表来记录事务状态。

批改 db-init 我的项目中的 order.sql 文件，创立 tx_table 表：

drop database if exists `seata_order`;

CREATE DATABASE `seata_order` charset utf8;

use `seata_order`;

CREATE TABLE `order` (`id` bigint(11) NOT NULL,
  `user_id` bigint(11) DEFAULT NULL COMMENT '用户 id',
  `product_id` bigint(11) DEFAULT NULL COMMENT '产品 id',
  `count` int(11) DEFAULT NULL COMMENT '数量',
  `money` decimal(11,0) DEFAULT NULL COMMENT '金额',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=7 DEFAULT CHARSET=utf8;

ALTER TABLE `order` ADD COLUMN `status` int(1) DEFAULT NULL COMMENT '订单状态：0：创立中；1：已完结' AFTER `money` ;

-- for AT mode you must to init this sql for you business database. the seata server not need it.
CREATE TABLE IF NOT EXISTS `undo_log`
(`branch_id`     BIGINT(20)   NOT NULL COMMENT 'branch transaction id',
    `xid`           VARCHAR(100) NOT NULL COMMENT 'global transaction id',
    `context`       VARCHAR(128) NOT NULL COMMENT 'undo_log context,such as serialization',
    `rollback_info` LONGBLOB     NOT NULL COMMENT 'rollback info',
    `log_status`    INT(11)      NOT NULL COMMENT '0:normal status,1:defense status',
    `log_created`   DATETIME(6)  NOT NULL COMMENT 'create datetime',
    `log_modified`  DATETIME(6)  NOT NULL COMMENT 'modify datetime',
    UNIQUE KEY `ux_undo_log` (`xid`, `branch_id`)
) ENGINE = InnoDB
  AUTO_INCREMENT = 1
  DEFAULT CHARSET = utf8 COMMENT ='AT transaction mode undo table';

CREATE TABLE IF NOT EXISTS segment
(
    id            BIGINT UNSIGNED AUTO_INCREMENT PRIMARY KEY COMMENT '自增主键',
    VERSION       BIGINT      DEFAULT 0  NOT NULL COMMENT '版本号',
    business_type VARCHAR(63) DEFAULT ''NOT NULL COMMENT' 业务类型，惟一 ',
    max_id        BIGINT      DEFAULT 0  NOT NULL COMMENT '以后最大 id',
    step          INT         DEFAULT 0  NULL COMMENT '步长',
    increment     INT         DEFAULT 1  NOT NULL COMMENT '每次 id 增量',
    remainder     INT         DEFAULT 0  NOT NULL COMMENT '余数',
    created_at    BIGINT UNSIGNED        NOT NULL COMMENT '创立工夫',
    updated_at    BIGINT UNSIGNED        NOT NULL COMMENT '更新工夫',
    CONSTRAINT uniq_business_type UNIQUE (business_type)
) CHARSET = utf8mb4
  ENGINE INNODB COMMENT '号段表';

INSERT INTO segment
(VERSION, business_type, max_id, step, increment, remainder, created_at, updated_at)
VALUES (1, 'order_business', 1000, 1000, 1, 0, NOW(), NOW());

CREATE TABLE tx_table(`xid` char(32) PRIMARY KEY COMMENT '事务 id',
    `status` int COMMENT '0- 提交，1- 回滚，2- 未知',
    `created_at` BIGINT UNSIGNED NOT NULL COMMENT '创立工夫'
);

运行 db-init 我的项目，会创立这个表：

order 发送事务音讯，并执行本地事务

Rocketmq 中增加 Topic

应用 order-topic 来收发音讯，在 Rocketmq 服务器上创立这个 Topic：

order-parent 中增加 rocketmq 起步依赖

批改 pom.xml 增加以下内容：

在 properties 中设置 rocketmq 起步依赖的版本

<rocketmq-spring-boot-starter.version>2.1.0</rocketmq-spring-boot-starter.version>

增加 rocketmq 起步依赖：

<dependency>
    <groupId>org.apache.rocketmq</groupId>
    <artifactId>rocketmq-spring-boot-starter</artifactId>
    <version>${rocketmq-spring-boot-starter.version}</version>
</dependency>

order 我的项目中增加 rocketmq 连贯信息配置：

批改 order 我的项目的 application.yml，增加 NameServer 地址，指定生产者组名：

rocketmq:
  name-server: 192.168.64.151:9876;192.168.64.152:9876
  producer:
    group: order-group

增加 TxMapper 拜访事务状态表

事务状态保留到 tx_table 表，在 TxMapper 接口和 TxMapper.xml 中增加事务状态数据的读写办法。

本地事务执行后要保留事务信息（事务 id、事务状态）到数据库，以便之后进行事务回查，首先创立封装事务信息的类 TxInfo：

package cn.tedu.order.tx;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class TxInfo {
    private String xid;
    private Long created;
    private Integer status;
}

TxMapper 接口：

package cn.tedu.order.mapper;

import cn.tedu.order.tx.TxInfo;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;

public interface TxMapper extends BaseMapper<TxInfo> {Boolean exists(String xid);
}

TxMapper.xml：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="cn.tedu.order.mapper.TxMapper" >
    <resultMap id="BaseResultMap" type="cn.tedu.order.tx.TxInfo" >
        <id column="xid" property="xid" jdbcType="CHAR" />
        <result column="created_at" property="created" jdbcType="BIGINT" />
        <result column="status" property="status" jdbcType="INTEGER"/>
    </resultMap>

    <insert id="insert">
        INSERT INTO `tx_table`(`xid`,`created_at`,`status`) VALUES(#{xid},#{created},#{status});
    </insert>
    <select id="exists" resultType="boolean">
        SELECT COUNT(1) FROM tx_table WHERE xid=#{xid};
    </select>
    <select id="selectById" resultMap="BaseResultMap">
        SELECT `xid`,`created_at`,`status` FROM tx_table WHERE xid=#{xid};
    </select>
</mapper>

Json 解决工具

发送事务音讯时，咱们把事务对象序列化成 Json 字符串再发送。这里先增加一个工具 JsonUtil 用来解决 Json：

package cn.tedu.order.util;

import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Writer;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.lang3.StringUtils;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.fasterxml.jackson.datatype.jdk8.Jdk8Module;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class JsonUtil {
    private static ObjectMapper mapper;
    private static JsonInclude.Include DEFAULT_PROPERTY_INCLUSION = JsonInclude.Include.NON_DEFAULT;
    private static boolean IS_ENABLE_INDENT_OUTPUT = false;
    private static String CSV_DEFAULT_COLUMN_SEPARATOR = ",";
    static {
        try {initMapper();
            configPropertyInclusion();
            configIndentOutput();
            configCommon();} catch (Exception e) {log.error("jackson config error", e);
        }
    }

    private static void initMapper() {mapper = new ObjectMapper();
    }

    private static void configCommon() {config(mapper);
    }

    private static void configPropertyInclusion() {mapper.setSerializationInclusion(DEFAULT_PROPERTY_INCLUSION);
    }

    private static void configIndentOutput() {mapper.configure(SerializationFeature.INDENT_OUTPUT, IS_ENABLE_INDENT_OUTPUT);
    }

    private static void config(ObjectMapper objectMapper) {objectMapper.enable(JsonGenerator.Feature.WRITE_BIGDECIMAL_AS_PLAIN);
        objectMapper.enable(DeserializationFeature.ACCEPT_EMPTY_STRING_AS_NULL_OBJECT);
        objectMapper.enable(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY);
        objectMapper.enable(DeserializationFeature.FAIL_ON_READING_DUP_TREE_KEY);
        objectMapper.enable(DeserializationFeature.FAIL_ON_NUMBERS_FOR_ENUMS);
        objectMapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);
        objectMapper.disable(DeserializationFeature.FAIL_ON_NULL_FOR_PRIMITIVES);
        objectMapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);
        objectMapper.enable(JsonParser.Feature.ALLOW_COMMENTS);
        objectMapper.disable(JsonGenerator.Feature.ESCAPE_NON_ASCII);
        objectMapper.enable(JsonGenerator.Feature.IGNORE_UNKNOWN);
        objectMapper.enable(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES);
        objectMapper.disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS);
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
        objectMapper.enable(JsonParser.Feature.ALLOW_SINGLE_QUOTES);
        objectMapper.registerModule(new ParameterNamesModule());
        objectMapper.registerModule(new Jdk8Module());
        objectMapper.registerModule(new JavaTimeModule());
    }
    public static void setSerializationInclusion(JsonInclude.Include inclusion) {
        DEFAULT_PROPERTY_INCLUSION = inclusion;
        configPropertyInclusion();}

    public static void setIndentOutput(boolean isEnable) {
        IS_ENABLE_INDENT_OUTPUT = isEnable;
        configIndentOutput();}

    public static <V> V from(URL url, Class<V> c) {
        try {return mapper.readValue(url, c);
        } catch (IOException e) {log.error("jackson from error, url: {}, type: {}", url.getPath(), c, e);
            return null;
        }
    }

    public static <V> V from(InputStream inputStream, Class<V> c) {
        try {return mapper.readValue(inputStream, c);
        } catch (IOException e) {log.error("jackson from error, type: {}", c, e);
            return null;
        }
    }

    public static <V> V from(File file, Class<V> c) {
        try {return mapper.readValue(file, c);
        } catch (IOException e) {log.error("jackson from error, file path: {}, type: {}", file.getPath(), c, e);
            return null;
        }
    }

    public static <V> V from(Object jsonObj, Class<V> c) {
        try {return mapper.readValue(jsonObj.toString(), c);
        } catch (IOException e) {log.error("jackson from error, json: {}, type: {}", jsonObj.toString(), c, e);
            return null;
        }
    }

    public static <V> V from(String json, Class<V> c) {
        try {return mapper.readValue(json, c);
        } catch (IOException e) {log.error("jackson from error, json: {}, type: {}", json, c, e);
            return null;
        }
    }

    public static <V> V from(URL url, TypeReference<V> type) {
        try {return mapper.readValue(url, type);
        } catch (IOException e) {log.error("jackson from error, url: {}, type: {}", url.getPath(), type, e);
            return null;
        }
    }

    public static <V> V from(InputStream inputStream, TypeReference<V> type) {
        try {return mapper.readValue(inputStream, type);
        } catch (IOException e) {log.error("jackson from error, type: {}", type, e);
            return null;
        }
    }

    public static <V> V from(File file, TypeReference<V> type) {
        try {return mapper.readValue(file, type);
        } catch (IOException e) {log.error("jackson from error, file path: {}, type: {}", file.getPath(), type, e);
            return null;
        }
    }

    public static <V> V from(Object jsonObj, TypeReference<V> type) {
        try {return mapper.readValue(jsonObj.toString(), type);
        } catch (IOException e) {log.error("jackson from error, json: {}, type: {}", jsonObj.toString(), type, e);
            return null;
        }
    }

    public static <V> V from(String json, TypeReference<V> type) {
        try {return mapper.readValue(json, type);
        } catch (IOException e) {log.error("jackson from error, json: {}, type: {}", json, type, e);
            return null;
        }
    }

    public static <V> String to(List<V> list) {
        try {return mapper.writeValueAsString(list);
        } catch (JsonProcessingException e) {log.error("jackson to error, obj: {}", list, e);
            return null;
        }
    }

    public static <V> String to(V v) {
        try {return mapper.writeValueAsString(v);
        } catch (JsonProcessingException e) {log.error("jackson to error, obj: {}", v, e);
            return null;
        }
    }

    public static <V> void toFile(String path, List<V> list) {try (Writer writer = new FileWriter(new File(path), true)) {mapper.writer().writeValues(writer).writeAll(list);
            writer.flush();} catch (Exception e) {log.error("jackson to file error, path: {}, list: {}", path, list, e);
        }
    }

    public static <V> void toFile(String path, V v) {try (Writer writer = new FileWriter(new File(path), true)) {mapper.writer().writeValues(writer).write(v);
            writer.flush();} catch (Exception e) {log.error("jackson to file error, path: {}, obj: {}", path, v, e);
        }
    }

    public static String getString(String json, String key) {if (StringUtils.isEmpty(json)) {return null;}
        try {JsonNode node = mapper.readTree(json);
            if (null != node) {return node.get(key).asText();} else {return null;}
        } catch (IOException e) {log.error("jackson get string error, json: {}, key: {}", json, key, e);
            return null;
        }
    }

    public static Integer getInt(String json, String key) {if (StringUtils.isEmpty(json)) {return null;}
        try {JsonNode node = mapper.readTree(json);
            if (null != node) {return node.get(key).intValue();} else {return null;}
        } catch (IOException e) {log.error("jackson get int error, json: {}, key: {}", json, key, e);
            return null;
        }
    }

    public static Long getLong(String json, String key) {if (StringUtils.isEmpty(json)) {return null;}
        try {JsonNode node = mapper.readTree(json);
            if (null != node) {return node.get(key).longValue();} else {return null;}
        } catch (IOException e) {log.error("jackson get long error, json: {}, key: {}", json, key, e);
            return null;
        }
    }

    public static Double getDouble(String json, String key) {if (StringUtils.isEmpty(json)) {return null;}
        try {JsonNode node = mapper.readTree(json);
            if (null != node) {return node.get(key).doubleValue();} else {return null;}
        } catch (IOException e) {log.error("jackson get double error, json: {}, key: {}", json, key, e);
            return null;
        }
    }

    public static BigInteger getBigInteger(String json, String key) {if (StringUtils.isEmpty(json)) {return new BigInteger(String.valueOf(0.00));
        }
        try {JsonNode node = mapper.readTree(json);
            if (null != node) {return node.get(key).bigIntegerValue();} else {return null;}
        } catch (IOException e) {log.error("jackson get biginteger error, json: {}, key: {}", json, key, e);
            return null;
        }
    }

    public static BigDecimal getBigDecimal(String json, String key) {if (StringUtils.isEmpty(json)) {return null;}
        try {JsonNode node = mapper.readTree(json);
            if (null != node) {return node.get(key).decimalValue();} else {return null;}
        } catch (IOException e) {log.error("jackson get bigdecimal error, json: {}, key: {}", json, key, e);
            return null;
        }
    }

    public static boolean getBoolean(String json, String key) {if (StringUtils.isEmpty(json)) {return false;}
        try {JsonNode node = mapper.readTree(json);
            if (null != node) {return node.get(key).booleanValue();} else {return false;}
        } catch (IOException e) {log.error("jackson get boolean error, json: {}, key: {}", json, key, e);
            return false;
        }
    }

    public static byte[] getByte(String json, String key) {if (StringUtils.isEmpty(json)) {return null;}
        try {JsonNode node = mapper.readTree(json);
            if (null != node) {return node.get(key).binaryValue();} else {return null;}
        } catch (IOException e) {log.error("jackson get byte error, json: {}, key: {}", json, key, e);
            return null;
        }
    }

    public static <T> ArrayList<T> getList(String json, String key) {if (StringUtils.isEmpty(json)) {return null;}
        String string = getString(json, key);
        return from(string, new TypeReference<ArrayList<T>>() {});
    }

    public static <T> String add(String json, String key, T value) {
        try {JsonNode node = mapper.readTree(json);
            add(node, key, value);
            return node.toString();} catch (IOException e) {log.error("jackson add error, json: {}, key: {}, value: {}", json, key, value, e);
            return json;
        }
    }

    private static <T> void add(JsonNode jsonNode, String key, T value) {if (value instanceof String) {((ObjectNode) jsonNode).put(key, (String) value);
        } else if (value instanceof Short) {((ObjectNode) jsonNode).put(key, (Short) value);
        } else if (value instanceof Integer) {((ObjectNode) jsonNode).put(key, (Integer) value);
        } else if (value instanceof Long) {((ObjectNode) jsonNode).put(key, (Long) value);
        } else if (value instanceof Float) {((ObjectNode) jsonNode).put(key, (Float) value);
        } else if (value instanceof Double) {((ObjectNode) jsonNode).put(key, (Double) value);
        } else if (value instanceof BigDecimal) {((ObjectNode) jsonNode).put(key, (BigDecimal) value);
        } else if (value instanceof BigInteger) {((ObjectNode) jsonNode).put(key, (BigInteger) value);
        } else if (value instanceof Boolean) {((ObjectNode) jsonNode).put(key, (Boolean) value);
        } else if (value instanceof byte[]) {((ObjectNode) jsonNode).put(key, (byte[]) value);
        } else {((ObjectNode) jsonNode).put(key, to(value));
        }
    }

    public static String remove(String json, String key) {
        try {JsonNode node = mapper.readTree(json);
            ((ObjectNode) node).remove(key);
            return node.toString();} catch (IOException e) {log.error("jackson remove error, json: {}, key: {}", json, key, e);
            return json;
        }
    }

    public static <T> String update(String json, String key, T value) {
        try {JsonNode node = mapper.readTree(json);
            ((ObjectNode) node).remove(key);
            add(node, key, value);
            return node.toString();} catch (IOException e) {log.error("jackson update error, json: {}, key: {}, value: {}", json, key, value, e);
            return json;
        }
    }

    public static String format(String json) {
        try {JsonNode node = mapper.readTree(json);
            return mapper.writerWithDefaultPrettyPrinter().writeValueAsString(node);
        } catch (IOException e) {log.error("jackson format json error, json: {}", json, e);
            return json;
        }
    }

    public static boolean isJson(String json) {
        try {mapper.readTree(json);
            return true;
        } catch (Exception e) {log.error("jackson check json error, json: {}", json, e);
            return false;
        }
    }

    private static InputStream getResourceStream(String name) {return JsonUtil.class.getClassLoader().getResourceAsStream(name);
    }

    private static InputStreamReader getResourceReader(InputStream inputStream) {if (null == inputStream) {return null;}
        return new InputStreamReader(inputStream, StandardCharsets.UTF_8);
    }
}

废除 OrderServiceImpl 类

之前的业务实现类 OrderServiceImpl 废除，前面用一个新的类 TxOrderService 来代替。

OrderServiceImpl.java 间接删除即可。

TxOrderService 发送事务音讯

TxAccountMessage 封装发送给账户服务的数据：用户 id 和扣减金额。另外还封装了事务 id。

package cn.tedu.order.tx;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.math.BigDecimal;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class TxAccountMessage {
    Long userId;
    BigDecimal money;
    String xid;
}

在业务办法 create() 中不间接保留订单，而是发送事务音讯。

音讯收回后，会触发 TxListener 执行本地事务，它执行时会回调这里的 doCreate() 办法实现订单的保留。

package cn.tedu.order.tx;

import cn.tedu.order.entity.Order;
import cn.tedu.order.feign.EasyIdGeneratorClient;
import cn.tedu.order.mapper.OrderMapper;
import cn.tedu.order.mapper.TxMapper;
import cn.tedu.order.service.OrderService;
import cn.tedu.order.util.JsonUtil;
import lombok.extern.slf4j.Slf4j;
import org.apache.rocketmq.spring.core.RocketMQTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Primary;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.UUID;

@Slf4j
@Primary
@Service
public class TxOrderService implements OrderService {
    @Autowired
    private RocketMQTemplate rocketMQTemplate;
    @Autowired
    private OrderMapper orderMapper;
    @Autowired
    private TxMapper txMapper;
    @Autowired
    EasyIdGeneratorClient easyIdGeneratorClient;

    /*
    创立订单的业务办法
    这里批改为：只向 Rocketmq 发送事务音讯。*/
    @Override
    public void create(Order order) {
        // 产生事务 ID
        String xid = UUID.randomUUID().toString().replace("-", "");

        // 对事务相干数据进行封装，并转成 json 字符串
        TxAccountMessage sMsg = new TxAccountMessage(order.getUserId(), order.getMoney(), xid);
        String json = JsonUtil.to(sMsg);

        //json 字符串封装到 Spring Message 对象
        Message<String> msg = MessageBuilder.withPayload(json).build();

        // 发送事务音讯
        rocketMQTemplate.sendMessageInTransaction("order-topic:account", msg, order);
        log.info("事务音讯已发送");
    }

    // 本地事务，执行订单保留
    // 这个办法在事务监听器中调用
    @Transactional
    public void doCreate(Order order, String xid) {log.info("执行本地事务，保留订单");

        // 从全局惟一 id 发号器取得 id
        Long orderId = easyIdGeneratorClient.nextId("order_business");
        order.setId(orderId);

        orderMapper.create(order);

        log.info("订单已保留！事务日志已保留");
    }
}

TxListener 事务监听器

发送事务音讯后会触发事务监听器执行。

事务监听器有两个办法：

  • executeLocalTransaction()：执行本地事务
  • checkLocalTransaction()：负责响应 Rocketmq 服务器的事务回查操作

TxListener 监听器类：

package cn.tedu.order.tx;

import cn.tedu.order.entity.Order;
import cn.tedu.order.mapper.TxMapper;
import cn.tedu.order.util.JsonUtil;
import lombok.extern.slf4j.Slf4j;
import org.apache.rocketmq.spring.annotation.RocketMQTransactionListener;
import org.apache.rocketmq.spring.core.RocketMQLocalTransactionListener;
import org.apache.rocketmq.spring.core.RocketMQLocalTransactionState;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.Message;
import org.springframework.stereotype.Component;

@Slf4j
@Component
@RocketMQTransactionListener
public class TxListener implements RocketMQLocalTransactionListener {
    @Autowired
    private TxOrderService orderService;
    @Autowired
    private TxMapper txMapper;

    @Override
    public RocketMQLocalTransactionState executeLocalTransaction(Message message, Object o) {log.info("事务监听 - 开始执行本地事务");

        // 监听器中失去的 message payload 是 byte[]
        String json = new String((byte[]) message.getPayload());
        String xid = JsonUtil.getString(json, "xid");

        log.info("事务监听 -"+json);
        log.info("事务监听 - xid:"+xid);

        RocketMQLocalTransactionState state;
        int status = 0;
        Order order = (Order) o;

        try {orderService.doCreate(order, xid);

            log.info("本地事务执行胜利，提交音讯");
            state = RocketMQLocalTransactionState.COMMIT;
            status = 0;
        } catch (Exception e) {e.printStackTrace();
            log.info("本地事务执行失败，回滚音讯");
            state = RocketMQLocalTransactionState.ROLLBACK;
            status = 1;
        }

        TxInfo txInfo = new TxInfo(xid, System.currentTimeMillis(), status);
        txMapper.insert(txInfo);

        return state;
    }

    @Override
    public RocketMQLocalTransactionState checkLocalTransaction(Message message) {log.info("事务监听 - 回查事务状态");

        // 监听器中失去的 message payload 是 byte[]
        String json = new String((byte[]) message.getPayload());
        String xid = JsonUtil.getString(json, "xid");

        TxInfo txInfo = txMapper.selectById(xid);
        if (txInfo == null) {log.info("事务监听 - 回查事务状态 - 事务不存在："+xid);
            return RocketMQLocalTransactionState.UNKNOWN;
        }

        log.info("事务监听 - 回查事务状态 -"+ txInfo.getStatus());

        switch (txInfo.getStatus()) {
            case 0: return RocketMQLocalTransactionState.COMMIT;
            case 1: return RocketMQLocalTransactionState.ROLLBACK;
            default: return RocketMQLocalTransactionState.UNKNOWN;
        }
    }
}

启动订单我的项目进行测试

按程序启动我的项目：

  1. Eureka
  2. Easy Id Generator
  3. Order

调用保留订单，地址：
http://localhost:8083/create?userId=1&productId=1&count=10&money=100

察看控制台日志：


订单表：

事务表：

拜访 Rocketmq，查看事务音讯：

account 接管事务音讯，并执行本地事务

application.yml 增加 Rocketmq 连贯配置

rocketmq:
  name-server: 192.168.64.151:9876;192.168.64.152:9876

JsonUtil 工具类

同下面的代码。

TxConsumer 接管事务音讯，调用账户业务办法

接管的音讯转换成 TxAccountMessage 对象，这里先创立这个类：

package cn.tedu.account.tx;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.math.BigDecimal;

@Data
@NoArgsConstructor
@AllArgsConstructor
public class TxAccountMessage {
    Long userId;
    BigDecimal money;
    String xid;
}

TxConsumer 实现音讯监听，收到音讯后实现扣减金额业务：

package cn.tedu.account.tx;

import cn.tedu.account.service.AccountService;
import cn.tedu.account.util.JsonUtil;
import com.fasterxml.jackson.core.type.TypeReference;
import lombok.extern.slf4j.Slf4j;
import org.apache.rocketmq.spring.annotation.RocketMQMessageListener;
import org.apache.rocketmq.spring.core.RocketMQListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Slf4j
@Component
@RocketMQMessageListener(consumerGroup = "account-consumer-group", topic = "order-topic", selectorExpression = "account")
public class TxConsumer implements RocketMQListener<String> {
    @Autowired
    private AccountService accountService;

    @Override
    public void onMessage(String msg) {TxAccountMessage txAccountMessage = JsonUtil.from(msg, new TypeReference<TxAccountMessage>() {});
        log.info("收到音讯："+txAccountMessage);

        accountService.decrease(txAccountMessage.getUserId(), txAccountMessage.getMoney());
    }
}

AccountServiceImpl 增加事务注解

package cn.tedu.account.service;

import cn.tedu.account.mapper.AccountMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.math.BigDecimal;
@Service
public class AccountServiceImpl implements AccountService {
    @Autowired
    private AccountMapper accountMapper;

    @Transactional
    @Override
    public void decrease(Long userId, BigDecimal money) {accountMapper.decrease(userId,money);
    }
}

启动 account 我的项目进行测试

按程序启动我的项目：

  1. Eureka
  2. Easy Id Generator
  3. Account
  4. Order

account 我的项目启动时，会立刻从 Rocketmq 收到音讯，执行账户扣减业务：

order 本地事务失败测试

批改 TxOrderService 增加模仿异样：

package cn.tedu.order.tx;

import cn.tedu.order.entity.Order;
import cn.tedu.order.feign.EasyIdGeneratorClient;
import cn.tedu.order.mapper.OrderMapper;
import cn.tedu.order.mapper.TxMapper;
import cn.tedu.order.service.OrderService;
import cn.tedu.order.util.JsonUtil;
import lombok.extern.slf4j.Slf4j;
import org.apache.rocketmq.spring.core.RocketMQTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Primary;
import org.springframework.messaging.Message;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.UUID;

@Slf4j
@Primary
@Service
public class TxOrderService implements OrderService {
    @Autowired
    private RocketMQTemplate rocketMQTemplate;
    @Autowired
    private OrderMapper orderMapper;
    @Autowired
    private TxMapper txMapper;
    @Autowired
    EasyIdGeneratorClient easyIdGeneratorClient;

    /*
    创立订单的业务办法
    这里批改为：只向 Rocketmq 发送事务音讯。*/
    @Override
    public void create(Order order) {
        // 产生事务 ID
        String xid = UUID.randomUUID().toString().replace("-", "");

        // 对事务相干数据进行封装，并转成 json 字符串
        TxAccountMessage sMsg = new TxAccountMessage(order.getUserId(), order.getMoney(), xid);
        String json = JsonUtil.to(sMsg);

        //json 字符串封装到 Spring Message 对象
        Message<String> msg = MessageBuilder.withPayload(json).build();

        // 发送事务音讯
        log.info("开始发送事务音讯");
        rocketMQTemplate.sendMessageInTransaction("order-topic:account", msg, order);
        log.info("事务音讯已发送");
    }

    // 本地事务，执行订单保留
    // 这个办法在事务监听器中调用
    @Transactional
    public void doCreate(Order order, String xid) {log.info("执行本地事务，保留订单");

        // 从全局惟一 id 发号器取得 id
        Long orderId = easyIdGeneratorClient.nextId("order_business");
        order.setId(orderId);

        orderMapper.create(order);

        if (Math.random() < 0.5) {throw new RuntimeException("模仿异样");
        }

        log.info("订单已保留！事务日志已保留");
    }
}

调用保留订单，地址：
http://localhost:8083/create?userId=1&productId=1&count=10&money=100

本地事务失败后，会告诉 Rocketmq 回滚事务：

测试完后，将模仿异样代码正文掉

account 本地事务失败测试

批改 AccountServiceImpl，增加随机模仿异样：

package cn.tedu.account.service;

import cn.tedu.account.mapper.AccountMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.math.BigDecimal;
@Service
public class AccountServiceImpl implements AccountService {
    @Autowired
    private AccountMapper accountMapper;

    @Transactional
    @Override
    public void decrease(Long userId, BigDecimal money) {accountMapper.decrease(userId,money);

        if (Math.random() < 0.5) {throw new RuntimeException("模仿异样");
        }
    }
}

调用保留订单，地址：
http://localhost:8083/create?userId=1&productId=1&count=10&money=100

account 账户服务接管音讯后，如果解决失败，Rocketmq 会进行重试，直到解决胜利为止。

我的项目源码：https://gitee.com/benwang6/rocketmq-dtx

正文完
rocketmq
发表至： rocketmq
2020-12-14
 0
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