seata的AT模式入门使用

概述

在微服务中每个服务都是对应的自己的db，相对应的事务也是各管各的。那么在某些场景下自然就要分布式的事务管理，比如下单扣库存场景。

环境

java 1.8
seata 1.4.2
nacos 1.4.1
springboot 2.7.4

先准备好db中的表

CREATE TABLE `t_order` (
  `id` int NOT NULL AUTO_INCREMENT,
  `order_no` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `user_id` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `commodity_code` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `count` int DEFAULT '0',
  `amount` double(14,2) DEFAULT '0.00',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=69 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

CREATE TABLE `t_stock` (
  `id` int NOT NULL AUTO_INCREMENT,
  `commodity_code` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `name` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci DEFAULT NULL,
  `count` int DEFAULT '0',
  PRIMARY KEY (`id`),
  UNIQUE KEY `commodity_code` (`commodity_code`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;

CREATE TABLE `undo_log` (
  `id` bigint NOT NULL AUTO_INCREMENT COMMENT 'increment id',
  `branch_id` bigint 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 NOT NULL COMMENT '0:normal status,1:defense status',
  `log_created` datetime NOT NULL COMMENT 'create datetime',
  `log_modified` datetime NOT NULL COMMENT 'modify datetime',
  `ext` varchar(100) DEFAULT NULL COMMENT 'reserved field',
  PRIMARY KEY (`id`),
  UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8 COMMENT='AT transaction mode undo table';

项目结构

依赖情况

父依赖

<?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>2.7.4</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.fchan</groupId>
    <artifactId>tcc_demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>tcc_demo</name>
    <packaging>pom</packaging>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>

    <modules>
        <module>account</module>
        <module>order</module>
        <module>stock</module>
        <module>common</module>
    </modules>

    <dependencies>

    </dependencies>



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

</project>

公共依赖

<?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>
        <artifactId>tcc_demo</artifactId>
        <groupId>com.fchan</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <groupId>com.fchan</groupId>
    <artifactId>tcc_seata_common</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>common</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</artifactId>
        </dependency>

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

        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.3.2</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.30</version>
        </dependency>


        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.0</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <version>2021.0.4.0</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba.nacos</groupId>
            <artifactId>nacos-client</artifactId>
            <version>1.4.1</version>
        </dependency>


        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-seata</artifactId>
            <version>2021.0.4.0</version>
        </dependency>


    </dependencies>

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

</project>

订单服务依赖

<?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>
        <artifactId>tcc_demo</artifactId>
        <groupId>com.fchan</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <groupId>com.fchan</groupId>
    <artifactId>order</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>order</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>com.fchan</groupId>
            <artifactId>tcc_seata_common</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
            <version>3.1.4</version>
        </dependency>


        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-loadbalancer</artifactId>
            <version>3.1.4</version>
        </dependency>

    </dependencies>

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

</project>

库存服务依赖

<?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>
        <artifactId>tcc_demo</artifactId>
        <groupId>com.fchan</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <groupId>com.fchan</groupId>
    <artifactId>stock</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>stock</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</artifactId>
        </dependency>

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

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

        <dependency>
            <groupId>com.fchan</groupId>
            <artifactId>tcc_seata_common</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

    </dependencies>

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

</project>

yml配置参数

订单服务

server:
  port: 9011

# seata配置
seata:
  # 默认关闭，如需启用spring.datasource.dynami.seata需要同时开启
  enabled: true
  # Seata 应用编号，默认为 ${spring.application.name}
  application-id: ${spring.application.name}
  # Seata 事务组编号，用于 TC 集群名
  tx-service-group: default_tx_group
  # 关闭自动代理
  enable-auto-data-source-proxy: true
  # 服务配置项
  service:
    # 虚拟组和分组的映射
    vgroup-mapping:
      default_tx_group: default
  config:
    type: nacos
    nacos:
      serverAddr: xxx.xxx.xxx.xxx:8848
      group: SEATA_GROUP
      namespace: ""
      username: nacos
      password: nacos
      data-id: "seataServer.properties"
  registry:
    type: nacos
    nacos:
      application: seata-server
      server-addr: xxx.xxx.xxx.xxx:8848
      namespace: ""
      username: nacos
      password: nacos
spring:
  application:
    name: tccOrder
  datasource:
    url: jdbc:mysql://xxx.xxx.xxx.xxx:3306/seata_pay?useUnicode=true&characterEncoding=utf8&allowMultiQueries=true&rewriteBatchedStatements=true
    username: root
    password: mark10086
    driver-class-name: com.mysql.cj.jdbc.Driver
    hikari:
      minimum-idle: 5
      idle-timeout: 100000
      maximum-pool-size: 10
      max-lifetime: 100000
      connection-timeout: 30000
      connection-test-query: select 1
      validation-timeout: 500
  cloud:
    nacos:
      server-addr: xxx.xxx.xxx.xxx:8848
      discovery:
        group: SEATA_GROUP
mybatis-plus:
  mapper-locations: classpath:mapper/*.xml

库存服务yml配置

server:
  port: 9010


# seata配置
seata:
  # 默认关闭，如需启用spring.datasource.dynami.seata需要同时开启
  enabled: true
  # Seata 应用编号，默认为 ${spring.application.name}
  application-id: ${spring.application.name}
  # Seata 事务组编号，用于 TC 集群名
  tx-service-group: default_tx_group
  # 关闭自动代理
  enable-auto-data-source-proxy: true
  # 服务配置项
  service:
    # 虚拟组和分组的映射
    vgroup-mapping:
      default_tx_group: default
  config:
    type: nacos
    nacos:
      serverAddr: xxx.xxx.xxx.xxx:8848
      group: SEATA_GROUP
      namespace: ""
      data-id: "seataServer.properties"
      username: "nacos"
      password: "nacos"
  registry:
    type: nacos
    nacos:
      application: seata-server
      server-addr: xxx.xxx.xxx.xxx:8848
      namespace: ""
      group: SEATA_GROUP
      username: "nacos"
      password: "nacos"
spring:
  application:
    name: tccStock
  datasource:
    url: jdbc:mysql://xxx.xxx.xxx.xxx:3306/seata_pay?useUnicode=true&characterEncoding=utf8&allowMultiQueries=true&rewriteBatchedStatements=true
    username: root
    password: mark10086
    driver-class-name: com.mysql.cj.jdbc.Driver
    hikari:
      minimum-idle: 5
      idle-timeout: 100000
      maximum-pool-size: 10
      max-lifetime: 100000
      connection-timeout: 30000
      connection-test-query: select 1
      validation-timeout: 500
  cloud:
    nacos:
      server-addr: xxx.xxx.xxx.xxx:8848
      discovery:
        group: SEATA_GROUP
mybatis-plus:
  mapper-locations: classpath:mapper/*.xml

调用流程

订单服务模拟调用
在这里插入图片描述

库存服务模拟异常
在这里插入图片描述

此时查看下db情况，可以看到订单表中新插入一条数据，库存扣减了50，undolog中有2条记录。然后出发异常的时候会全局回滚。证明seata全局事务生效

在这里插入图片描述

原文链接：https://blog.csdn.net/weixin_43944305/article/details/127353836