Hmily实现TCC事务


Hmily实现TCC事务

业务说明

本实例通过Hmily实现ICC分布式事务,模拟两个账户的转账交易过程。

两个账户分别在不同的银行(张三在bank1、李四在bank2) , bank1. bank2是两个微服务。 交易过程
是,张三给李四转账指定金额。

上述交易步骤,要么一起成功，要么一起失败,必须是一个整体性的事务。
在这里插入图片描述

程序组成部分

数据库：MySQL-8.X （包括bank1和bank2 两个数据库）
JDK:1.8.X
微服务框架：SpringBoot2.3、SpringCloudHoxton
Hmily：hmily-springcloud.2.0.4
微服务及数据库的关系：
dtx/hmily-bank-tcc/bank1-server 银行1 操作张三用户，连接bank1
dtx/hmily-bank-tcc/bank1-server 银行2 操作李四用户，连接bank2

服务注册中心：nacos

创建数据库

创建Hmily数据库，用于存储hmily框记录的数据，运行时自动添加表

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CREATE DATABASE `hmily` CHARACTER SET `utf8mb4` ;

bank1库，包含张三的账户

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DROP DATABASE IF  EXISTS  `bank1`;
CREATE DATABASE `bank1` CHARACTER SET 'utf8mb4';

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USE `bank1`;

DROP TABLE IF EXISTS `account_info`;
CREATE TABLE `account_info` (
        id bigint ( 20 ) NOT NULL  AUTO_INCREMENT COMMENT '主键',
        account_name VARCHAR ( 100 ) COMMENT '账户姓名',
        account_no VARCHAR ( 100 ) COMMENT '账户卡号',
        account_password VARCHAR ( 100 ) COMMENT '账户密码',
        account_balance DECIMAL ( 10,2) COMMENT '账户余额',
        PRIMARY KEY ( id )
) COMMENT = '账户表';

INSERT INTO `account_info` VALUES ('1' , '张三的账户','1', '', 10000 );

bank2库，包含李四的账户

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DROP DATABASE IF  EXISTS  `bank2`;
CREATE DATABASE `bank2` CHARACTER SET 'utf8mb4';
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USE `bank2`;

DROP TABLE IF EXISTS `account_info`;
CREATE TABLE `account_info` (
        id bigint ( 20 ) NOT NULL  AUTO_INCREMENT COMMENT '主键',
        account_name VARCHAR ( 100 ) COMMENT '账户姓名',
        account_no VARCHAR ( 100 ) COMMENT '账户卡号',
        account_password VARCHAR ( 100 ) COMMENT '账户密码',
        account_balance DECIMAL ( 10,2)  COMMENT '账户余额',
        PRIMARY KEY ( id )
) COMMENT = '账户表';

INSERT INTO `account_info` VALUES ('1' , '李四的账户','2', '', 0);

每个数据库都创建try、confirm、cancelsa

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CREATE TABLE `local_try_log` (
`tx_no` varchar(64) not NUll comment '事务Id',
`create_time` datetime DEFAULT NULL,
PRIMARY KEY (`tx_no`)
);

CREATE TABLE `local_confirm_log` (
`tx_no` varchar(64) not NUll comment '事务Id',
`create_time` datetime DEFAULT NULL,
PRIMARY KEY (`tx_no`)
);

CREATE TABLE `local_cancel_log` (
`tx_no` varchar(64) not NUll comment '事务Id',
`create_time` datetime DEFAULT NULL,
PRIMARY KEY (`tx_no`)
);

搭建项目

  1. pom.xml
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<?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>2.3.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.wry.dtx</groupId>
    <artifactId>bank1-server-tcc</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>bank1-server-tcc</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Hoxton.SR5</spring-cloud.version>
        <spring-cloud-alibaba.version>2.2.0.RELEASE</spring-cloud-alibaba.version>
        <mybatis-plus.version>3.3.2</mybatis-plus.version>
        <mysql.version>8.0.19</mysql.version>
        <hmily.version>2.0.0-RELEASE</hmily.version>
    </properties>

    <dependencies>
        <!--hmily -->
        <dependency>
            <groupId>org.dromara</groupId>
            <artifactId>hmily-spring-boot-starter-springcloud</artifactId>
            <version>${hmily.version}</version>
            <exclusions>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId></exclusion>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-netflix-eureka-client</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <!-- openfeign -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--注册中心客户端-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>${mysql.version}</version>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>${mybatis-plus.version}</version>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring-cloud-alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

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

</project>
  1. application.yml
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server:
  port: 8003

spring:
  application:
    name: bank1-server-tcc
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://39.96.3.100:3306/bank1?allowPublicKeyRetrieval=true&useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT+8&nullCatalogMeansCurrent=true
    username: root
    password: 123456
  cloud:
    nacos:
      discovery:
        server-addr: 39.96.3.100:8848

logging:
  level:
    root: info

mybatis-plus:
  mapper-locations: classpath:/mapper/*.xml
  typeAliasesPackage: com.wry.dtx.bank1.entity
  global-config:
    db-config:
      field-strategy: not-empty
      id-type: auto
      db-type: mysql

ribbon:
  ReadTimeout: 3000
  ConnectTimeout: 3000

org:
  dromara:
    hmily :
      serializer : kryo
      recoverDelayTime : 128
      retryMax : 30
      scheduledDelay : 128
      scheduledThreadMax :  10
      repositorySupport : db
      started: true
      hmilyDbConfig :
        driverClassName  : com.mysql.cj.jdbc.Driver
        url :  jdbc:mysql://39.96.3.100:3306/hmily?allowPublicKeyRetrieval=true&useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT+8&nullCatalogMeansCurrent=true
        username : root
        password : 123456
  1. 启动类
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package com.wry.dtx.bank1;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.EnableAspectJAutoProxy;

@SpringBootApplication
@EnableDiscoveryClient
@EnableAspectJAutoProxy
@EnableFeignClients(basePackages = {"com.wry.dtx.bank1.feign"})
@ComponentScan({"org.dromara.hmily","com.wry.dtx.bank1"})
public class Bank1ServerTccApplication {

    public static void main(String[] args) {
        SpringApplication.run(Bank1ServerTccApplication.class, args);
    }

}

具体代码可参考Github:https://github.com/hobbyWang/DistributedTransaction/tree/master/hmily-bank-tcc

小结

如果拿TCC事务的处理流程与2PC两阶段提交做比较，2PC通常都是在跨库的DB层面，而TCC则在应用层面的处 理，需要通过业务逻辑来实现。这种分布式事务的实现方式的优势在于，可以让应用自己定义数据操作的粒度，使得降低锁冲突、提高吞吐量成为可能。 而不足之处则在于对应用的侵入性非常强，业务逻辑的每个分支都需要实现try、confirm、cancel三个操作。此 外，其实现难度也比较大，需要按照网络状态、系统故障等不同的失败原因实现不同的回滚策略。