SpringCloud - Spring Cloud Alibaba 之 Seata分布式事务服务；AT事务模式（二十）

「爱情、让人受尽委屈。」 2023-09-28 18:31 20阅读 0赞

#### 阅读本文前可先参考： ####

[https://blog.csdn.net/MinggeQingchun/article/details/126100300][https_blog.csdn.net_MinggeQingchun_article_details_126100300]

[https://blog.csdn.net/MinggeQingchun/article/details/126176893][https_blog.csdn.net_MinggeQingchun_article_details_126176893]

## AT 模式 ##

[Seata AT 模式][Seata AT]

#### 前提 ####

1、基于支持本地 ACID 事务的关系型数据库

2、Java 应用，通过 JDBC 访问数据库

#### 整体机制 ####

两阶段提交协议的演变：

1、一阶段：业务数据和回滚日志记录在同一个本地事务中提交，释放本地锁和连接资源

2、二阶段：

（1）提交异步化，非常快速地完成

（2）回滚通过一阶段的回滚日志进行反向补偿

#### 写隔离 ####

1、一阶段本地事务提交前，需要确保先拿到 **全局锁**

2、拿不到 **全局锁** ，不能提交本地事务

3、拿 **全局锁** 的尝试被限制在一定范围内，超出范围将放弃，并回滚本地事务，释放本地锁

#### 读隔离 ####

在数据库本地事务隔离级别 **读已提交（Read Committed）** 或以上的基础上，Seata（AT 模式）的默认全局隔离级别是 **读未提交（Read Uncommitted）** 。

如果应用在特定场景下，必需要求全局的 **读已提交** ，目前 Seata 的方式是通过 SELECT FOR UPDATE 语句的代理。

## 一、AT事务模式：SpringBoot单体应用多数据源AT分布式事务 ##

![de1a882a1585409cb98c09dd1c115139.png][]

在Spring Boot单体项目中，使用了多数据源，就要保证多个数据源的数据一致性，即产生了分布式事务的问题，采用Seata的AT事务模式来解决该分布式事务问题

以下图购物下单为例

![050c3df109e54595bc5068490d297794.png][]

#### 1、创建数据库、表、插入数据等 ####

（1）accountdb账户库、account账户表

SET NAMES utf8mb4;
    SET FOREIGN_KEY_CHECKS = 0;
    
    -- ----------------------------
    -- Table structure for account
    -- ----------------------------
    DROP TABLE IF EXISTS `account`;
    CREATE TABLE `account`  (
      `id` int(20) NOT NULL AUTO_INCREMENT,
      `user_id` int(20) NULL DEFAULT NULL,
      `balance` decimal(20, 0) NULL DEFAULT NULL,
      `update_time` datetime(6) NULL DEFAULT NULL,
      PRIMARY KEY (`id`) USING BTREE
    ) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
    
    SET FOREIGN_KEY_CHECKS = 1;

（2）productdb产品库、product产品表

SET NAMES utf8mb4;
    SET FOREIGN_KEY_CHECKS = 0;
    
    -- ----------------------------
    -- Table structure for product
    -- ----------------------------
    DROP TABLE IF EXISTS `product`;
    CREATE TABLE `product`  (
      `id` int(20) NOT NULL AUTO_INCREMENT,
      `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
      `price` decimal(10, 2) NULL DEFAULT NULL,
      `stock` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
      `add_time` datetime(6) NULL DEFAULT NULL,
      `update_time` datetime(6) NULL DEFAULT NULL,
      PRIMARY KEY (`id`) USING BTREE
    ) ENGINE = InnoDB AUTO_INCREMENT = 2 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
    
    SET FOREIGN_KEY_CHECKS = 1;

（3）orderdb订单库、orders 订单表

SET NAMES utf8mb4;
    SET FOREIGN_KEY_CHECKS = 0;
    
    -- ----------------------------
    -- Table structure for orders
    -- ----------------------------
    DROP TABLE IF EXISTS `orders`;
    CREATE TABLE `orders`  (
      `id` int(20) NOT NULL AUTO_INCREMENT,
      `user_id` int(20) NULL DEFAULT NULL,
      `product_id` int(20) NULL DEFAULT NULL,
      `pay_amount` decimal(20, 0) NULL DEFAULT NULL,
      `add_time` datetime(6) NULL DEFAULT NULL,
      `update_time` datetime(6) NULL DEFAULT NULL,
      PRIMARY KEY (`id`) USING BTREE
    ) ENGINE = InnoDB AUTO_INCREMENT = 6 CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;
    
    SET FOREIGN_KEY_CHECKS = 1;

（4）undo\_log表

[Seata AT 模式][Seata AT]

-- 注意此处0.7.0+ 增加字段 context
    CREATE TABLE `undo_log` (
      `id` bigint(20) NOT NULL AUTO_INCREMENT,
      `branch_id` bigint(20) NOT NULL,
      `xid` varchar(100) NOT NULL,
      `context` varchar(128) NOT NULL,
      `rollback_info` longblob NOT NULL,
      `log_status` int(11) NOT NULL,
      `log_created` datetime NOT NULL,
      `log_modified` datetime NOT NULL,
      PRIMARY KEY (`id`),
      UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

注：

每个库必须创建 undo\_log 表，是 Seata AT模式必须创建的表，主要用于分支事务的回滚

![736430a464d3487eb7a6842a4c36d4a0.png][]

[Seata AT 模式][Seata AT]

![937693cb145e41e2bc5df395aa1ebd69.png][]

![1d9c991463d248e3ad3b07ca3afcccfd.png][]

#### 2、创建 SpringBoot单体应用 ####

1、创建一个 springboot应用，命名 springcloud-alibaba-2-seata-distributed-transaction

2、添加依赖（非Spring CLoud 微服务项目，没有Spring CLoud依赖）

<groupId>com.company</groupId>
        <artifactId>springcloud-alibaba-2-seata-distributed-transaction</artifactId>
        <version>1.0.0</version>
    
        <name>springcloud-alibaba-2-seata-distributed-transaction</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>1.8</java.version>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <spring-boot.version>2.3.12.RELEASE</spring-boot.version>
            <spring-cloud-alibaba.version>2.2.7.RELEASE</spring-cloud-alibaba.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-actuator</artifactId>
            </dependency>
    
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-test</artifactId>
                <scope>test</scope>
                <exclusions>
                    <exclusion>
                        <groupId>org.junit.vintage</groupId>
                        <artifactId>junit-vintage-engine</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
    
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
    
            </dependency>
    
            
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.1.3</version>
            </dependency>
    
            
            <dependency>
                <groupId>io.seata</groupId>
                <artifactId>seata-spring-boot-starter</artifactId>
                <version>1.3.0</version>
            </dependency>
    
            
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
                <version>3.2.0</version>
            </dependency>
    
        </dependencies>
    
        
        <dependencyManagement>
            <dependencies>
                <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>
                
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>Hoxton.SR12</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-dependencies</artifactId>
                    <version>${spring-boot.version}</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <configuration>
                        <source>1.8</source>
                        <target>1.8</target>
                        <encoding>UTF-8</encoding>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
                
                <plugin>
                    <groupId>org.mybatis.generator</groupId>
                    <artifactId>mybatis-generator-maven-plugin</artifactId>
                    <version>1.4.0</version>
                    <configuration>
                        
                        <configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
                        
                        <verbose>true</verbose>
                        
                        <overwrite>true</overwrite>
                    </configuration>
                </plugin>
            </plugins>
    
            <resources>
                <resource>
                    <directory>src/main/java</directory>
                    <includes>
                        <include>**/*.xml</include>
                    </includes>
                </resource>
                <resource>
                    <directory>src/main/resources</directory>
                    <includes>
                        <include>**/*.*</include>
                    </includes>
                </resource>
            </resources>
        </build>

3、application.properties配置文件

#内嵌服务器端口
    server.port=8081
    
    #应用服务名称
    spring.application.name=springcloud-alibaba-2-seata-distributed-transaction
    
    # 设置默认的数据源或者数据源组，默认值即为master
    spring.datasource.dynamic.primary=order-ds
    
    # 订单order数据源配置
    spring.datasource.dynamic.datasource.order-ds.url=jdbc:mysql://localhost:3306/orderdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&rewriteBatchedStatements=true&useSSL=false
    spring.datasource.dynamic.datasource.order-ds.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.dynamic.datasource.order-ds.username=root
    spring.datasource.dynamic.datasource.order-ds.password=admin123456
    
    # 商品product数据源配置
    spring.datasource.dynamic.datasource.product-ds.url=jdbc:mysql://localhost:3306/productdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&rewriteBatchedStatements=true&useSSL=false
    spring.datasource.dynamic.datasource.product-ds.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.dynamic.datasource.product-ds.username=root
    spring.datasource.dynamic.datasource.product-ds.password=admin123456
    
    # 账户account数据源配置
    spring.datasource.dynamic.datasource.account-ds.url=jdbc:mysql://localhost:3306/accountdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&rewriteBatchedStatements=true&useSSL=false
    spring.datasource.dynamic.datasource.account-ds.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.dynamic.datasource.account-ds.username=root
    spring.datasource.dynamic.datasource.account-ds.password=admin123456
    
    # 是否启动对Seata的集成
    spring.datasource.dynamic.seata=true
    
    
    #-----------------------------------------------------------
    #单机版 tc server 配置
    # Seata应用编号，默认为 ${spring.application.name}
    seata.application-id=springboot-seata
    # Seata事务组编号，用于TC集群名，一般格式为：${spring.application.name}-group
    seata.tx-service-group=springboot-seata-group
    # 虚拟组和分组的映射 seata.service.vgroup-mapping.${seata.tx-service-group}=default
    seata.service.vgroup-mapping.springboot-seata-group=default
    # 分组和Seata服务的映射，此处default指上面 seata.service.vgroup-mapping.springboot-seata-group 的值 default
    seata.service.grouplist.default=192.168.133.129:8091
    # 存储模式 默认 file模式
    seata.config.type=file
    # 默认为 file
    seata.registry.type=file
    #------------------------------------------------------------

4、编写相应的 controller、model、mapper、service类，这里只给出调用顺序相关的类

controller测试类

order逻辑类

注：

（1）**@DS**注解；多数据源切换

（2）**@GlobalTransactional**注解；seata全局事务注解

**主服务加上@GlobalTransactional注解即可，被调用服务不用加@GlobalTransactional和@Transactional**

@Slf4j
    @Service
    public class OrderServiceImpl implements OrderService {
    
        @Autowired
        private OrdersMapper ordersMapper;
    
        @Autowired
        private AccountService accountService;
    
        @Autowired
        private ProductService productService;
    
        @Override
        /**
         * MyBatis-Plus 使用 @DS注解 做多数据源切换
         * 语法：@DS(value = "数据源名称")
         * 1、依赖：
         *         <dependency>
         *             <groupId>com.baomidou</groupId>
         *             <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
         *             <version>3.0.0</version>
         *         </dependency>
         * 2、yml 或 properties 配置
         * # 设置默认的数据源或者数据源组，默认值即为master
         * spring.datasource.dynamic.primary=order-ds
         *
         * # 订单order数据源配置
         * spring.datasource.dynamic.datasource.order-ds.url=jdbc:mysql://localhost:3306/orderdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&rewriteBatchedStatements=true&useSSL=false
         * spring.datasource.dynamic.datasource.order-ds.driver-class-name=com.mysql.cj.jdbc.Driver
         * spring.datasource.dynamic.datasource.order-ds.username=root
         * spring.datasource.dynamic.datasource.order-ds.password=admin123456
         *
         * # 商品product数据源配置
         * spring.datasource.dynamic.datasource.product-ds.url=jdbc:mysql://localhost:3306/productdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&rewriteBatchedStatements=true&useSSL=false
         * spring.datasource.dynamic.datasource.product-ds.driver-class-name=com.mysql.cj.jdbc.Driver
         * spring.datasource.dynamic.datasource.product-ds.username=root
         * spring.datasource.dynamic.datasource.product-ds.password=admin123456
         * 3、@DS注解到实现类或者实现类的方法上才可以
         * 当注解添加到类上，意味着此类里的方法都使用此数据源；
         * 当注解添加到方法上时，意味着此方法上使用的数据源优先级高于其他一切配置
         * 注：
         * （1）注解添加在dao.mapper上无效
         * （2）注解添加到interface Service类上无效
         * （3）注解添加到interface Service方法上无效
         */
        @DS(value = "order-ds")
        @GlobalTransactional //seata全局事务注解
        public Integer createOrder(Integer userId, Integer productId) throws Exception {
            Integer amount = 1; // 购买数量暂时设置为 1
    
            log.info("当前 XID: {}", RootContext.getXID());
    
            //1、减库存
            Product product = productService.reduceStock(productId, amount);
    
            //2、减余额
            accountService.reduceBalance(userId, product.getPrice());
    
            //3、下订单
            Orders order = new Orders();
            order.setUserId(userId);
            order.setProductId(productId);
            order.setPayAmount(product.getPrice().multiply(new BigDecimal(amount)));
            order.setAddTime(new Date());
            ordersMapper.insertSelective(order);
    
            //造成异常，测试是否回滚
            //int a = 10/0;
    
            log.info("下订单: {}", order.getId());
    
            // 返回订单编号
            return order.getId();
        }
    }

product逻辑类

@Slf4j
    @Service
    public class ProductServiceImpl implements ProductService {
    
        @Autowired
        private ProductMapper productMapper;
    
        @Override
        @DS(value = "product-ds")
        public Product reduceStock(Integer productId, Integer amount) throws Exception {
            log.info("当前 XID: {}", RootContext.getXID());
    
            // 检查库存
            Product product = productMapper.selectByPrimaryKey(productId);
            if (product.getStock() < amount) {
                throw new Exception("库存不足");
            }
    
            // 扣减库存
            int updateCount = productMapper.reduceStock(productId, amount);
            // 扣除成功
            if (updateCount == 0) {
                throw new Exception("库存不足");
            }
    
            //造成异常，测试是否回滚
            //int a = 10/0;
    
            // 扣除成功
            log.info("扣除 {} 库存成功", productId);
    
            return product;
        }
    }

account逻辑类

@Slf4j
    @Service
    public class AccountServiceImpl implements AccountService {
    
        @Autowired
        private AccountMapper accountMapper;
    
        @Override
        @DS(value = "account-ds")
        public void reduceBalance(Integer userId, BigDecimal money) throws Exception {
            log.info("当前 XID: {}", RootContext.getXID());
    
            // 检查余额
            Account account = accountMapper.selectAccountByUserId(userId);
            if (account.getBalance().doubleValue() < money.doubleValue()) {
                throw new Exception("余额不足");
            }
    
            // 扣除余额
            int updateCount = accountMapper.reduceBalance(userId, money);
            // 扣除成功
            if (updateCount == 0) {
                throw new Exception("余额不足");
            }
    
            //造成异常，测试是否回滚
            //int a = 10/0;
    
            log.info("扣除用户 {} 余额成功", userId);
        }
    }

5、启动seata-server；浏览器输入访问 [http://localhost:8081/order?userId=1&productId=1][http_localhost_8081_order_userId_1_productId_1]

可分别在 OrderServiceImpl、ProductServiceImpl、AccountServiceImpl 实现类中 写入如下代码进行事务回滚测试

//造成异常，测试是否回滚
    int a = 10/0;

### @DS注解 ###

MyBatis-Plus 使用 @DS注解 做多数据源切换

语法：

> @DS(value = "数据源名称")

1、依赖：

<dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
                <version>3.2.0</version>
            </dependency>

2、yml 或 properties 配置

# 设置默认的数据源或者数据源组，默认值即为master
    spring.datasource.dynamic.primary=order-ds
    
    # 订单order数据源配置
    spring.datasource.dynamic.datasource.order-ds.url=jdbc:mysql://localhost:3306/orderdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&rewriteBatchedStatements=true&useSSL=false
    spring.datasource.dynamic.datasource.order-ds.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.dynamic.datasource.order-ds.username=root
    spring.datasource.dynamic.datasource.order-ds.password=admin123456
    
    # 商品product数据源配置
    spring.datasource.dynamic.datasource.product-ds.url=jdbc:mysql://localhost:3306/productdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&rewriteBatchedStatements=true&useSSL=false
    spring.datasource.dynamic.datasource.product-ds.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.dynamic.datasource.product-ds.username=root
    spring.datasource.dynamic.datasource.product-ds.password=admin123456
    
    # 账户account数据源配置
    spring.datasource.dynamic.datasource.account-ds.url=jdbc:mysql://localhost:3306/accountdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&rewriteBatchedStatements=true&useSSL=false
    spring.datasource.dynamic.datasource.account-ds.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.dynamic.datasource.account-ds.username=root
    spring.datasource.dynamic.datasource.account-ds.password=admin123456

3、@DS注解到实现类或者实现类的方法上才可以

当注解添加到类上，意味着此类里的方法都使用此数据源；

当注解添加到方法上时，意味着此方法上使用的数据源优先级高于其他一切配置

注：

（1）注解添加在dao.mapper上无效

（2）注解添加到interface Service类上无效

（3）注解添加到interface Service方法上无效

> 注：
> 
> **如果try catch 异常 则不会回滚事务**

## 二、AT事务模式：Spring Cloud Alibaba微服务AT分布式事务 ##

![0eb051d8a8a845eead62fd77059b6bb7.png][]

1、临时关闭Linux上防火墙，或者设置端口访问权限

systemctl stop firewalld

2、 因Nacos使用mysql持久化，需要先开启 mysql服务（手动安装或者docker启动，docker启动需要先启动docker和挂载mysql服务，不然重启docker或者mysql导致mysql数据丢失）

3、首先启动nacos服务

sh startup.sh -m standalone

> **单机环境必须带-m standalone参数启动；不带参数启动的是集群环境**

4、因Seata server 使用的 Nacos 注册中心，需要配置 conf/registry.conf 文件，选择nacos

Seata Server 配置  
在 Seata Server 安装目录下的 config/registry.conf 中，将配置方式（config.type）修改为 Nacos，并对 Nacos 配置中心的相关信息进行配置

如果使用了 注册中心 ，如 type="nacos"等要检查nacos的 应用名application、服务注册地址serverAddr、分组group、命名空间namespace、集群cluster、用户名username、密码password是否正确等

config {
      # Seata 支持 file、nacos 、apollo、zk、consul、etcd3 等多种配置中心
      #配置方式修改为 nacos
      type = "nacos"
     
      nacos {
        #修改为使用的 nacos 服务器地址
        serverAddr = "127.0.0.1:8848"
        #配置中心的命名空间
        namespace = ""
        #配置中心所在的分组
        group = "SEATA_GROUP"
        #Nacos 配置中心的用户名
        username = "nacos"
        #Nacos 配置中心的密码
        password = "nacos"
      }
    }

![2d0d645bcd374067b675797dd6d1934b.png][]

不然报错：

no available service found in cluster 'default', please make sure registry config correct and keep your seata server running

![604804deca4a48939d0a5185d3979e64.jpeg][]**Seata Client 配置**

在 Seata Client（即微服务架构中的服务）中，通过 application.yml 等配置文件对 Nacos 配置中心进行配置

#-----------------------------------------------------------
    #单机版 tc server 配置
    # Seata应用编号，默认为 ${spring.application.name}
    seata.application-id=springcloud-order-seata
    # Seata事务组编号，用于TC集群名，一般格式为：${spring.application.name}-group
    seata.tx-service-group=springcloud-order-seata-group
    # 注：虚拟组和分组的映射要写对，不然报错：
    # no available service 'null' found, please make sure registry config correct
    # 虚拟组和分组的映射 seata.service.vgroup-mapping.${seata.tx-service-group}=default
    seata.service.vgroup-mapping.springcloud-order-seata-group=default
    # 分组和Seata服务的映射，此处default指上面 seata.service.vgroup-mapping.springboot-seata-group 的值 default
    #seata.service.grouplist.default=192.168.133.129:8091
    # 存储模式 默认 file模式
    seata.config.type=file
    # 默认为 file
    #seata.registry.type=file
    #------------------------------------------------------------
     
     
    #设置使用注册中心
    #seata-spring-boot-starter 1.1版本少一些配置项
    seata.enabled=true
    seata.registry.type=nacos
    # 集群
    seata.registry.nacos.cluster=default
    # 分组
    seata.registry.nacos.group=SEATA_GROUP
    # 应用名
    seata.registry.nacos.application=seata-server
    # 服务注册地址
    seata.registry.nacos.server-addr=192.168.133.129:8848

注：！！！

Seata应用编号 seata.application-id，默认为 $\{spring.application.name\}

Seata事务组编号 seata.tx-service-group，用于TC集群名，一般格式为：$\{spring.application.name\}-group

Seata虚拟组和分组的映射 seata.service.vgroup-mapping.$\{seata.tx-service-group\}=default

三者对应关系要写对，不然会报错：

no available service 'null' found, please make sure registry config correct

###  ###

### 测试应用 ###

1、创建 4 个SpringBoot 模块

#### （1）springcloud-alibaba-2-seata-distributed-commons ####

<dependencies>
            
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>1.18.16</version>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-openfeign</artifactId>
                <version>3.0.0</version>
            </dependency>
        </dependencies>

@FeignClient(name = "springcloud-alibaba-2-seata-distributed-account")
    public interface FeignAccountService {
    
        /**
         * 扣除余额
         *
         * @param userId 用户ID
         * @param money  扣减金额
         * @throws Exception 失败时抛出异常
         */
        @PostMapping("/account/reduceBalance")
        void reduceBalance(@RequestParam("userId") Integer userId, @RequestParam("money") BigDecimal money);
    }
    
    
    @FeignClient(name = "springcloud-alibaba-2-seata-distributed-order")
    public interface FeignOrderService {
    
        /**
         * 创建订单
         *
         * @param userId 用户ID
         * @param productId 产品ID
         * @return 订单编号
         * @throws Exception 创建订单失败，抛出异常
         */
        Integer createOrder(Integer userId, Integer productId) throws Exception;
    
    }
    
    @FeignClient(name = "springcloud-alibaba-2-seata-distributed-product")
    public interface FeignProductService {
    
        /**
         * 减库存
         *
         * @param productId 商品ID
         * @param amount    扣减数量
         * @throws Exception 扣减失败时抛出异常
         */
        @PostMapping("/product/reduceStock")
        Product reduceStock(@RequestParam("productId") Integer productId, @RequestParam("amount") Integer amount);
    }

#### （2）springcloud-alibaba-2-seata-distributed-order ####

注意：

1、异常需要层层往上抛，如果你在子服务将异常处理的话（比如全局异常处理GlobalExceptionHandler），seata会认为你已经手动处理了异常

2、出现事务失效的情况下，优先检查 RootContext.getXID() ，xid是否传递且一致

3、主服务加上@GlobalTransactional注解即可，被调用服务不用加@GlobalTransactional和@Transactional

4、@GlobalTransactional(rollbackFor = Exception.class)最好加上rollbackFor = Exception.class，表示遇到Exception都回滚，不然遇到有些异常（如自定义异常）则不会回滚

@Slf4j //lombok
    @RestController
    public class OrderController {
    
        @Autowired
        private OrderService orderService;
    
        @RequestMapping("/order")
        public Integer createOrder(@RequestParam("userId") Integer userId,
                                   @RequestParam("productId") Integer productId) throws Exception {
    
            log.info("请求下单, 用户:{}, 商品:{}", userId, productId);
    
            return orderService.createOrder(userId, productId);
        }
    }
    
    
    @Slf4j
    @Service
    public class OrderServiceImpl implements OrderService {
    
        @Autowired
        private OrdersMapper ordersMapper;
    
        @Autowired
        private FeignAccountService accountService;
    
        @Autowired
        private FeignProductService productService;
    
        @Override
        @GlobalTransactional //seata全局事务注解
        public Integer createOrder(Integer userId, Integer productId) {
            Integer amount = 1; // 购买数量暂时设置为 1
    
            log.info("当前 XID: {}", RootContext.getXID());
    
            //1、减库存
            Product product = productService.reduceStock(productId, amount);
    
            //2、减余额
            accountService.reduceBalance(userId, product.getPrice());
    
            //3、下订单
            Orders order = new Orders();
            order.setUserId(userId);
            order.setProductId(productId);
            order.setPayAmount(product.getPrice().multiply(new BigDecimal(amount)));
            order.setAddTime(new Date());
            ordersMapper.insertSelective(order);
    
            //造成异常，测试是否回滚
            int a = 10/0;
    
            log.info("下订单: {}", order.getId());
    
            // 返回订单编号
            return order.getId();
        }
    }

<groupId>com.company</groupId>
        <artifactId>springcloud-alibaba-2-seata-distributed-order</artifactId>
        <version>1.0.0</version>
    
        <name>springcloud-alibaba-2-seata-distributed-order</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>1.8</java.version>
            <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
            <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
            <spring-boot.version>2.3.12.RELEASE</spring-boot.version>
            <spring-cloud-alibaba.version>2.2.7.RELEASE</spring-cloud-alibaba.version>
        </properties>
    
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-web</artifactId>
            </dependency>
    
            
            <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-test</artifactId>
                <scope>test</scope>
                <exclusions>
                    <exclusion>
                        <groupId>org.junit.vintage</groupId>
                        <artifactId>junit-vintage-engine</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
    
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>2.1.3</version>
            </dependency>
    
            
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-seata</artifactId>
                <exclusions>
                    <exclusion>
                        <groupId>io.seata</groupId>
                        <artifactId>seata-spring-boot-starter</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
    
            
            <dependency>
                <groupId>io.seata</groupId>
                <artifactId>seata-spring-boot-starter</artifactId>
                <version>1.4.2</version>
            </dependency>
    
            
            <dependency>
                <groupId>com.company</groupId>
                <artifactId>springcloud-alibaba-2-seata-distributed-commons</artifactId>
                <version>1.0.0</version>
            </dependency>
    
        </dependencies>
    
        
        <dependencyManagement>
            <dependencies>
                <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>
                
                <dependency>
                    <groupId>org.springframework.cloud</groupId>
                    <artifactId>spring-cloud-dependencies</artifactId>
                    <version>Hoxton.SR12</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
                <dependency>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-dependencies</artifactId>
                    <version>${spring-boot.version}</version>
                    <type>pom</type>
                    <scope>import</scope>
                </dependency>
            </dependencies>
        </dependencyManagement>
    
        <build>
            <plugins>
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
                    <version>3.8.1</version>
                    <configuration>
                        <source>1.8</source>
                        <target>1.8</target>
                        <encoding>UTF-8</encoding>
                    </configuration>
                </plugin>
                <plugin>
                    <groupId>org.springframework.boot</groupId>
                    <artifactId>spring-boot-maven-plugin</artifactId>
                </plugin>
            </plugins>
    
            <resources>
                <resource>
                    <directory>src/main/java</directory>
                    <includes>
                        <include>**/*.xml</include>
                    </includes>
                </resource>
                <resource>
                    <directory>src/main/resources</directory>
                    <includes>
                        <include>**/*.*</include>
                    </includes>
                </resource>
            </resources>
        </build>

注：！！！

seata-spring-boot-starter 服务端和客户端版本要一致，不然报错：

no available service 'default' found, please make sure registry config correct

server.port=8081
    
    spring.application.name=springcloud-alibaba-2-seata-distributed-order
    
    spring.datasource.url=jdbc:mysql://192.168.133.129:3306/orderdb?serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf8&rewriteBatchedStatements=true&useSSL=false
    spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
    spring.datasource.username=root
    spring.datasource.password=123456
    
    #nacos服务的注册与发现
    spring.cloud.nacos.discovery.server-addr=192.168.133.129:8848
    # 用户名、密码为默认时，测试发现不写 用户名、密码也可以
    spring.cloud.nacos.username=nacos
    spring.cloud.nacos.password=nacos
    
    
    #-----------------------------------------------------------
    #单机版 tc server 配置
    # Seata应用编号，默认为 ${spring.application.name}
    seata.application-id=springcloud-order-seata
    # Seata事务组编号，用于TC集群名，一般格式为：${spring.application.name}-group
    seata.tx-service-group=springcloud-order-seata-group
    # 注：虚拟组和分组的映射要写对，不然报错：
    # no available service 'null' found, please make sure registry config correct
    # 虚拟组和分组的映射 seata.service.vgroup-mapping.${seata.tx-service-group}=default
    seata.service.vgroup-mapping.springcloud-order-seata-group=default
    # 分组和Seata服务的映射，此处default指上面 seata.service.vgroup-mapping.springboot-seata-group 的值 default
    #seata.service.grouplist.default=192.168.133.129:8091
    # 存储模式 默认 file模式
    seata.config.type=file
    # 默认为 file
    #seata.registry.type=file
    #------------------------------------------------------------
    
    
    #设置使用注册中心
    #seata-spring-boot-starter 1.1版本少一些配置项
    seata.enabled=true
    seata.registry.type=nacos
    # 集群
    seata.registry.nacos.cluster=default
    # 分组
    seata.registry.nacos.group=SEATA_GROUP
    # 应用名
    seata.registry.nacos.application=seata-server
    # 服务注册地址
    seata.registry.nacos.server-addr=192.168.133.129:8848
    
    #feign超时时间设置
    feign.client.config.default.connect-timeout=60000
    feign.client.config.default.read-timeout=60000

#### （3）springcloud-alibaba-2-seata-distributed-product ####

@Slf4j
    @Service
    public class ProductServiceImpl implements ProductService {
    
        @Autowired
        private ProductMapper productMapper;
    
        @Override
        public Product reduceStock(Integer productId, Integer amount) throws Exception {
            log.info("当前 XID: {}", RootContext.getXID());
    
            // 检查库存
            Product product = productMapper.selectByPrimaryKey(productId);
            if (product.getStock() < amount) {
                throw new Exception("库存不足");
            }
    
            // 扣减库存
            int updateCount = productMapper.reduceStock(productId, amount);
            // 扣除成功
            if (updateCount == 0) {
                throw new Exception("库存不足");
            }
    
            //造成异常，测试是否回滚
            //int a = 10/0;
    
            // 扣除成功
            log.info("扣除 {} 库存成功", productId);
    
            return product;
        }
    }

#### （4）springcloud-alibaba-2-seata-distributed-account ####

@Slf4j
    @Service
    public class AccountServiceImpl implements AccountService {
    
        @Autowired
        private AccountMapper accountMapper;
    
        @Override
        public void reduceBalance(Integer userId, BigDecimal money) throws Exception {
            log.info("当前 XID: {}", RootContext.getXID());
    
            // 检查余额
            Account account = accountMapper.selectAccountByUserId(userId);
            if (account.getBalance().doubleValue() < money.doubleValue()) {
                throw new Exception("余额不足");
            }
    
            // 扣除余额
            int updateCount = accountMapper.reduceBalance(userId, money);
            // 扣除成功
            if (updateCount == 0) {
                throw new Exception("余额不足");
            }
    
            //造成异常，测试是否回滚
            //int a = 10/0;
    
            log.info("扣除用户 {} 余额成功", userId);
        }
    }

2、先启动Nacos，再启动Seata-Server

Nacos中注册服务列表如下：

![311358e845ed42d68a45dec5ebef422d.png][]

> 注：
> 
> **如果try catch 异常 则不会回滚事务**

## 三、遇到问题 ##

### 1、启动seata server遇到问题 ###

报错如下：

Failed to retry rollbacking [192.168.133.129:8091:702852926242021399] Unknown java.lang.RuntimeException: rm client is not connected.
    dbkey:jdbc:mysql://localhost:3306/orderdb,clientId:springboot-seata:192.168.133.1:64279

因之前博主测试 AT事务模式：单体应用多数据源分布式事务，导致 /bin/sessionStore/root.data 中含有回滚数据 ，但是连接的 数据库url是错误的，将其修改掉或者直接删除

rm -rf root.data

重新启动即可

启动seata server 报错也可参考

[https://blog.csdn.net/MinggeQingchun/article/details/126172351][https_blog.csdn.net_MinggeQingchun_article_details_126172351]

### 2、 no available service 'null' found, please make sure registry config correct ###

### no available service 'default' found, please make sure registry config correct ###

### no available service found in cluster 'default', please make sure registry config correct and keep your seata server running ###

启动项目时因为 Seata 服务注册到Nacos 出现过如下三种错误：

#### （1） no available service 'null' found, please make sure registry config correct ####

Seata应用编号 seata.application-id，默认为 $\{spring.application.name\}

Seata事务组编号 seata.tx-service-group，用于TC集群名，一般格式为：$\{spring.application.name\}-group

Seata虚拟组和分组的映射 seata.service.vgroup-mapping.$\{seata.tx-service-group\}=default

![b2148e060b5c49d696904800b75dec5b.png][]三者对应关系要写对，不然会报错：

no available service 'null' found, please make sure registry config correct

#### （2）no available service 'default' found, please make sure registry config correct ####

博主 Seata Server 使用 1.4.2 版本

![50044c97aeeb40d3900c075d83c79dd5.png][]

<dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-starter-alibaba-seata</artifactId>
                <exclusions>
                    <exclusion>
                        <groupId>io.seata</groupId>
                        <artifactId>seata-spring-boot-starter</artifactId>
                    </exclusion>
                </exclusions>
            </dependency>
     
            
     
    <dependency>
        <groupId>io.seata</groupId>
        <artifactId>seata-spring-boot-starter</artifactId>
        <version>1.4.2/version>
    </dependency>
     
    <dependency>
        <groupId>com.alibaba.nacos</groupId>
        <artifactId>nacos-client</artifactId>
        <version>1.2.0及以上版本</version>
    </dependency>

seata-spring-boot-starter 服务端和客户端版本要一致，不然报错：

no available service 'default' found, please make sure registry config correct

![070b052266164d0b886c2b966b1c6f42.jpeg][]

#### （3）no available service found in cluster 'default', please make sure registry config correct and keep your seata server running ####

使用了 注册中心 ，如 type="nacos"等要检查nacos的 应用名application、服务注册地址serverAddr、分组group、命名空间namespace、集群cluster、用户名username、密码password是否正确等

![2d0d645bcd374067b675797dd6d1934b.png][]

不然报错：

no available service found in cluster 'default', please make sure registry config correct and keep your seata server running

![13f5c452459f4f879240c425c08fe4e7.jpeg][]

### 3、 @GlobalTransactional注解 无效，事务不会滚 ###

具体可参考

[Seata常见问题][Seata]

[通过AOP动态创建/关闭Seata分布式事务][AOP_Seata]

[集成 spring-cloud-starter-alibaba-seata @GlobalTransactional 失效的问题 - 来世还做程序员 - 博客园][spring-cloud-starter-alibaba-seata _GlobalTransactional _ - _ -]

[openfeign+seata+zipkin通过feign请求服务栈溢出异常的问题\_陌生人的魅力的博客-CSDN博客][openfeign_seata_zipkin_feign_-CSDN]

[feign调用服务，被调用服务seata事务不开启或者xid为空\_广铁小多多的博客-CSDN博客\_seata xid不一致][feign_seata_xid_-CSDN_seata xid][Seata分布式事务失效，不生效（事务不回滚）的常见场景\_godkzz的博客-CSDN博客\_seata回滚不生效][Seata_godkzz_-CSDN_seata]

[seata事务无法回滚情况\_slivloon的博客-CSDN博客\_seata事务不回滚原因][seata_slivloon_-CSDN_seata]

[https_blog.csdn.net_MinggeQingchun_article_details_126100300]: https://blog.csdn.net/MinggeQingchun/article/details/126100300
[https_blog.csdn.net_MinggeQingchun_article_details_126176893]: https://blog.csdn.net/MinggeQingchun/article/details/126176893
[Seata AT]: http://seata.io/zh-cn/docs/dev/mode/at-mode.html
[de1a882a1585409cb98c09dd1c115139.png]: https://img-blog.csdnimg.cn/de1a882a1585409cb98c09dd1c115139.png
[050c3df109e54595bc5068490d297794.png]: https://img-blog.csdnimg.cn/050c3df109e54595bc5068490d297794.png
[736430a464d3487eb7a6842a4c36d4a0.png]: https://img-blog.csdnimg.cn/736430a464d3487eb7a6842a4c36d4a0.png
[937693cb145e41e2bc5df395aa1ebd69.png]: https://img-blog.csdnimg.cn/937693cb145e41e2bc5df395aa1ebd69.png
[1d9c991463d248e3ad3b07ca3afcccfd.png]: https://img-blog.csdnimg.cn/1d9c991463d248e3ad3b07ca3afcccfd.png
[http_localhost_8081_order_userId_1_productId_1]: http://localhost:8081/order?userId=1&productId=1
[0eb051d8a8a845eead62fd77059b6bb7.png]: https://img-blog.csdnimg.cn/0eb051d8a8a845eead62fd77059b6bb7.png
[2d0d645bcd374067b675797dd6d1934b.png]: https://img-blog.csdnimg.cn/2d0d645bcd374067b675797dd6d1934b.png
[604804deca4a48939d0a5185d3979e64.jpeg]: https://img-blog.csdnimg.cn/604804deca4a48939d0a5185d3979e64.jpeg
[311358e845ed42d68a45dec5ebef422d.png]: https://img-blog.csdnimg.cn/311358e845ed42d68a45dec5ebef422d.png
[https_blog.csdn.net_MinggeQingchun_article_details_126172351]: https://blog.csdn.net/MinggeQingchun/article/details/126172351
[b2148e060b5c49d696904800b75dec5b.png]: https://img-blog.csdnimg.cn/b2148e060b5c49d696904800b75dec5b.png
[50044c97aeeb40d3900c075d83c79dd5.png]: https://img-blog.csdnimg.cn/50044c97aeeb40d3900c075d83c79dd5.png
[070b052266164d0b886c2b966b1c6f42.jpeg]: https://img-blog.csdnimg.cn/070b052266164d0b886c2b966b1c6f42.jpeg
[13f5c452459f4f879240c425c08fe4e7.jpeg]: https://img-blog.csdnimg.cn/13f5c452459f4f879240c425c08fe4e7.jpeg
[Seata]: https://seata.io/zh-cn/docs/overview/faq.html
[AOP_Seata]: http://seata.io/zh-cn/blog/seata-spring-boot-aop-aspectj.html
[spring-cloud-starter-alibaba-seata _GlobalTransactional _ - _ -]: https://www.cnblogs.com/run-yard/p/15739934.html
[openfeign_seata_zipkin_feign_-CSDN]: https://blog.csdn.net/qq_15009805/article/details/122411512
[feign_seata_xid_-CSDN_seata xid]: https://blog.csdn.net/zdb1314/article/details/124211553
[Seata_godkzz_-CSDN_seata]: https://blog.csdn.net/godkzz/article/details/122398887?spm=1001.2101.3001.6661.1&utm_medium=distribute.pc_relevant_t0.none-task-blog-2~default~CTRLIST~default-1-122398887-blog-124211553.pc_relevant_multi_platform_whitelistv1&depth_1-utm_source=distribute.pc_relevant_t0.none-task-blog-2~default~CTRLIST~default-1-122398887-blog-124211553.pc_relevant_multi_platform_whitelistv1&utm_relevant_index=1
[seata_slivloon_-CSDN_seata]: https://blog.csdn.net/qq_36155375/article/details/115950439