SpringCloud - Spring Cloud Alibaba 之 Seata分布式事务服务;Seata TC Server集群部署(二十二)

Seata TC Server集群部署

生产环境下,我们需要部署集群 Seata TC Server,实现高可用。

集群时,多个 Seata TC Server 通过 db 数据库或者redis实现全局事务会话信息的共享

每个Seata TC Server注册自己到注册中心上,应用从注册中心获得Seata TC Server实例

 

Seata TC Server 集群搭建具体步骤(采用Nacos注册中心):

1、 下载并解压两份seata-server-1.4.2.tar.gz;

2、 初始化SeataTCServer的db数据库,在MySQL中,创建seata数据库,并在该库下执行如下SQL脚本:;

通过Seata官网下载1.4.2版本的 source

下载中心

 

使用seata-1.4.2\script\server\db脚本(MySQL)

-- -------------------------------- The script used when storeMode is 'db' --------------------------------
-- the table to store GlobalSession data
CREATE TABLE IF NOT EXISTS global_table
(
    xid                       VARCHAR(128) NOT NULL,
    transaction_id            BIGINT,
    status                    TINYINT      NOT NULL,
    application_id            VARCHAR(32),
    transaction_service_group VARCHAR(32),
    transaction_name          VARCHAR(128),
    timeout                   INT,
    begin_time                BIGINT,
    application_data          VARCHAR(2000),
    gmt_create                DATETIME,
    gmt_modified              DATETIME,
    PRIMARY KEY (xid),
    KEY idx_gmt_modified_status (gmt_modified, status),
    KEY idx_transaction_id (transaction_id)
) ENGINE = InnoDB
  DEFAULT CHARSET = utf8;

-- the table to store BranchSession data
CREATE TABLE IF NOT EXISTS branch_table
(
    branch_id         BIGINT       NOT NULL,
    xid               VARCHAR(128) NOT NULL,
    transaction_id    BIGINT,
    resource_group_id VARCHAR(32),
    resource_id       VARCHAR(256),
    branch_type       VARCHAR(8),
    status            TINYINT,
    client_id         VARCHAR(64),
    application_data  VARCHAR(2000),
    gmt_create        DATETIME(6),
    gmt_modified      DATETIME(6),
    PRIMARY KEY (branch_id),
    KEY idx_xid (xid)
) ENGINE = InnoDB
  DEFAULT CHARSET = utf8;

-- the table to store lock data
CREATE TABLE IF NOT EXISTS lock_table
(
    row_key        VARCHAR(128) NOT NULL,
    xid            VARCHAR(128),
    transaction_id BIGINT,
    branch_id      BIGINT       NOT NULL,
    resource_id    VARCHAR(256),
    table_name     VARCHAR(32),
    pk             VARCHAR(36),
    gmt_create     DATETIME,
    gmt_modified   DATETIME,
    PRIMARY KEY (row_key),
    KEY idx_branch_id (branch_id)
) ENGINE = InnoDB
  DEFAULT CHARSET = utf8;

3、 修改seata/conf/file.conf配置文件,修改使用db数据库,实现SeataTCServer的全局事务会话信息的共享;

(1)mode = "db"

(2)数据库的连接信息

driverClassName = "com.mysql.cj.jdbc.Driver"

url= "jdbc:mysql://IP:3306/seata"

user = "root"

password = "123456"

 

4、 设置使用Nacos注册中心;

修改seata/conf/registry.conf 配置文件,设置使用 Nacos 注册中心;

(1)type = "nacos"

(2)Nacos连接信息:

nacos {
application = "seata-server"
serverAddr = "127.0.0.1:8848"
group = "SEATA_GROUP"
namespace = ""
cluster = "default"
username = "nacos"
password = "nacos"
}

5、 启动MySQL数据库和Nacos注册中心;

6、 启动两个TCServer;

执行./seata-server.sh -p 18091 -n 1 命令,启动第一个TC Server;

-p:Seata TC Server 监听的端口;

-n:Server node,在多个 TC Server 时,需区分各自节点,用于生成不同区间的 transactionId 事务编号,以免冲突;

执行./seata-server.sh -p 28091 -n 2 命令,启动第二个TC Server

注:

如果使用虚拟机,最好修改内存为256MB

 

7、 打开Nacos注册中心控制台,可以看到有两个SeataTCServer实例;

 

 

8、 应用测试;

一、AT事务模式:单体应用SpringBoot多数据源分布式事务

 

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

 

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

-- 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

Seata AT 模式

 

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SpringCLoud微服务项目,没有SpringCLoud依赖);

主要添加 Nacos-client依赖

<!-- nacos-client -->
        <dependency>
            <groupId>com.alibaba.nacos</groupId>
            <artifactId>nacos-client</artifactId>
            <version>2.1.0</version>
        </dependency>
<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>

        <!-- mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
<!--            <version>8.0.28</version>-->
        </dependency>

        <!-- mybatis-spring-boot-starter -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.3</version>
        </dependency>

        <!-- seata-spring-boot-starter -->
        <dependency>
            <groupId>io.seata</groupId>
            <artifactId>seata-spring-boot-starter</artifactId>
            <version>1.3.0</version>
        </dependency>

        <!-- dynamic-datasource-spring-boot-starter动态数据源 -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
            <version>3.2.0</version>
        </dependency>

        <!-- nacos-client -->
        <dependency>
            <groupId>com.alibaba.nacos</groupId>
            <artifactId>nacos-client</artifactId>
            <version>2.1.0</version>
        </dependency>
    </dependencies>

    <!-- dependencyManagement标签 通常适用于多模块环境下定义一个top module来专门管理公共依赖的情况
        在子项目中不写该依赖项,那么子项目仍然会从父项目depenManagement中继承该artifactId和groupId依赖项(全部继承)
        若子项目 中dependencies中的dependency声明了version,则父项目中dependencyManagement中的声明无效

        Spring Cloud、Spring Cloud Alibaba 以及 Spring Boot 之间版本依赖参考官网
        https://github.com/alibaba/spring-cloud-alibaba/wiki/%E7%89%88%E6%9C%AC%E8%AF%B4%E6%98%8E
    -->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring-cloud-alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- spring-cloud-dependencies -->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.SR12</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${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>
            <!--mybatis代码自动生成插件-->
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.4.0</version>
                <configuration>
                    <!--配置文件的位置-->
                    <configurationFile>src/main/resources/generatorConfig.xml</configurationFile>
                    <!--生成代码过程中是否打印日志-->
                    <verbose>true</verbose>
                    <!--生成时是否覆盖java文件,xml文件总是合并-->
                    <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
#------------------------------------------------------------
#------------------------------------------------------------
#集群版 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
#------------------------------------------------------------

#设置使用注册中心
seata.registry.type=nacos
seata.registry.nacos.cluster=default
seata.registry.nacos.application=seata-server
seata.registry.nacos.group=SEATA_GROUP
seata.registry.nacos.server-addr=192.168.133.129:8848

seata.enable-auto-data-source-proxy=false
seata.client.rm.lock.retry-policy-branch-rollback-on-conflict=false

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

@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);
    }
}

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

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;

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;

二、AT事务模式:微服务SpringCloud的分布式事务

 

1、 创建4个SpringBoot模块;

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

<dependencies>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.16</version>
        </dependency>

        <!--spring-cloud-starter-openfeign-->
        <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;

依赖注意如下:

(1)本身有 spring-cloud-starter-alibaba-nacos-discovery 依赖,不再需要额外添加 nacos-client 依赖

(2)spring-cloud-starter-alibaba-seata 包含 seata-spring-boot-starter 依赖,但是有些配置有问题,需要自己导入和Seata Server 版本相同的依赖

<!-- spring-cloud-starter-alibaba-seata
            在 Spring Cloud 项目中,spring-cloud依赖 也会引入 seata-spring-boot-starter 依赖,在此排除
         -->
        <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>

        <!-- seata-spring-boot-starter
            注: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
         -->
        <dependency>
            <groupId>io.seata</groupId>
            <artifactId>seata-spring-boot-starter</artifactId>
            <version>1.4.2</version>
        </dependency>
<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>

        <!--spring-cloud-starter-alibaba-sentinel-->
        <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>

        <!-- mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <!-- mybatis-spring-boot-starter -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.3</version>
        </dependency>

        <!-- spring-cloud-starter-alibaba-seata
            在 Spring Cloud 项目中,spring-cloud依赖 也会引入 seata-spring-boot-starter 依赖,在此排除
         -->
        <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>

        <!-- seata-spring-boot-starter
            注: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
         -->
        <dependency>
            <groupId>io.seata</groupId>
            <artifactId>seata-spring-boot-starter</artifactId>
            <version>1.4.2</version>
        </dependency>

        <!--统一通用项目,model类、openfeign接口-->
        <dependency>
            <groupId>com.company</groupId>
            <artifactId>springcloud-alibaba-2-seata-distributed-commons</artifactId>
            <version>1.0.0</version>
        </dependency>

    </dependencies>

    <!-- dependencyManagement标签 通常适用于多模块环境下定义一个top module来专门管理公共依赖的情况
        在子项目中不写该依赖项,那么子项目仍然会从父项目depenManagement中继承该artifactId和groupId依赖项(全部继承)
        若子项目 中dependencies中的dependency声明了version,则父项目中dependencyManagement中的声明无效

        Spring Cloud、Spring Cloud Alibaba 以及 Spring Boot 之间版本依赖参考官网
        https://github.com/alibaba/spring-cloud-alibaba/wiki/%E7%89%88%E6%9C%AC%E8%AF%B4%E6%98%8E
    -->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>${spring-cloud-alibaba.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- spring-cloud-dependencies -->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.SR12</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${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>
@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
    //seata全局事务注解;name要唯一
    @GlobalTransactional//(name = "seata-order-GlobalTransactional",rollbackFor = Exception.class)
    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();
    }
}

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