【精品】seata综合示例：订单-库存-扣款

有关seata的安装，请参看博客：https://blog.csdn.net/lianghecai52171314/article/details/127330916

业务需求：下单—减库存—扣钱—改订单状态

当用户下单时，会在订单服务中创建一个订单，然后通过远程调用库存服务来扣减下单商品的库存；再通过远程调用账户服务来扣减用户账户里面的余额；最后订单服务中修改订单状态。

需要涉及到三个模块：

模块名	数据库名	port	Context-path	Application-name
fafu-account	seata_account	3001	fafu	Fafu-account-3001
fafu-storage	seata_storage	4001	fafu	Fafu-storage-4001
fafu-order	seata_order	5001	fafu	Fafu-order-5001

可以看出：该操作需要跨域三个数据库，有两次远程调用，需要用到分布式事务技术。

数据库准备

创建seata_order数据库，然后在其中创建表tb_order：

CREATE TABLE `tb_order`  (`id` bigint UNSIGNED NOT NULL COMMENT '订单编号',`user_id` bigint UNSIGNED NULL DEFAULT NULL COMMENT '用户编号',`sku_id` bigint UNSIGNED NULL DEFAULT NULL COMMENT '商品编号',`count` int UNSIGNED NULL DEFAULT NULL COMMENT '数量',`money` decimal(10, 3) UNSIGNED NULL DEFAULT NULL COMMENT '金额',`state` int UNSIGNED NULL DEFAULT NULL COMMENT '状态',PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;

上面表的设计只是模拟性质的，大概对应的是拼多多的业务，一个订单中只能购买1种商品，但这种商品可以购买多个。

创建seata_storage数据库，然后在其中创建表tb_storage

CREATE TABLE `tb_storage`  (`id` bigint UNSIGNED NOT NULL COMMENT '编号',`sku_id` bigint UNSIGNED NULL DEFAULT NULL COMMENT '商品编号',`total` int UNSIGNED NULL DEFAULT NULL COMMENT '总库存',`used` int UNSIGNED NULL DEFAULT NULL COMMENT '已用库存',PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;

创建seata_account数据库，然后在其中创建表tb_account：

CREATE TABLE `tb_account`  (`id` bigint UNSIGNED NOT NULL COMMENT '编号',`total` decimal(11, 3) UNSIGNED NULL DEFAULT NULL COMMENT '总额度',`used` decimal(11, 3) UNSIGNED NULL DEFAULT NULL COMMENT '已用额度',PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;

依次在三个数据库创建undo_log 表，用于保存需要回滚的数据：

CREATE TABLE `undo_log`  (`id` bigint NOT NULL AUTO_INCREMENT,`branch_id` bigint NOT NULL,`xid` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,`context` varchar(128) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL,`rollback_info` longblob NOT NULL,`log_status` int NOT NULL,`log_created` datetime NOT NULL,`log_modified` datetime NOT NULL,`ext` varchar(100) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,PRIMARY KEY (`id`) USING BTREE,UNIQUE INDEX `ux_undo_log`(`xid` ASC, `branch_id` ASC) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

注：每个服务对应的业务数据库都需要创建这个日志表。

项目共同部分

Nacos中

在Nacos添加给客户端加载使用的配置seata-client-demo.yml：

Data Id：seata-client-demo.yml
Group：SEATA_GROUP

注意：上面配置中的group和nampespace都是在Nacos中创建命名空间时创建的。
上面配置的具体内容如下：

# seata配置
seata:enabled: trueapplication-id: seata-cilent-deme# Seata 事务组编号，此处需于 seata 相同tx-service-group: default-tx-groupconfig:type: nacosnacos:# nacos ip地址server-addr: 127.0.0.1:8848group: SEATA_GROUPnamespace: 99970600-6f67-43fd-a2a2-4e9795947bf4data-id: seata-server.propertiesregistry:type: nacosnacos:application: seata-server# nacos ip地址server-addr: 127.0.0.1:8848group: SEATA_GROUPnamespace: 99970600-6f67-43fd-a2a2-4e9795947bf4

依赖

<dependency><groupId>org.projectlombok</groupId><artifactId>lombok</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-devtools</artifactId><scope>runtime</scope><optional>true</optional>
</dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope>
</dependency><!-- 持久层相关 -->
<dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-starter</artifactId>
</dependency>
<dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId>
</dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<!--  nacos自从2020版本之后不再整合的是Netflix，也就没有ribbon了 -->
<dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-loadbalancer</artifactId>
</dependency>
<dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
</dependency>
<!-- sentinel配置持久化到Nacos -->
<dependency><groupId>com.alibaba.csp</groupId><artifactId>sentinel-datasource-nacos</artifactId>
</dependency><dependency><groupId>io.seata</groupId><artifactId>seata-spring-boot-starter</artifactId><version>1.5.2</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>

Result

@Getter
@ToString
public class Result<T> {/*** 请求响应状态码*/private int code;/*** 请求结果描述信息*/private String msg;/*** 请求结果数据*/private T data;public Result<T> setCode(int code) {this.code = code;return this;}public Result<T> setMsg(String msg) {this.msg = msg;return this;}public Result<T> setData(T data) {this.data = data;return this;}public static void main(String[] args) {Result<Object> result = new Result<>().addData("a", "aaa", "b", 123, "c", new Date());System.out.println(result);}/*** 将key-value形式的成对出现的参数转换为JSON** @param objs* @return*/public Result<T> addData(Object... objs) {if (objs.length % 2 != 0) {throw new RuntimeException("参数个数不对");}for (int i = 0; i < objs.length; i += 2) {if (!(objs[i] instanceof String)) {throw new RuntimeException("奇数参数必须为字符串");}}Map<String, Object> map = new HashMap<>();for (int i = 0; i < objs.length; i += 2) {map.put((String) objs[i], objs[i + 1]);}this.data = (T) map;return this;}
}

ResultUtil

public class ResultUtil {public static <T> Result<T> success() {Result<T> result = new Result<>();result.setCode(200);result.setMsg("成功");return result;}public static <T> Result<T> success(Integer code, String msg) {Result<T> result = new Result<>();result.setCode(code);result.setMsg(msg);return result;}public static <T> Result<T> success(T data) {Result<T> result = new Result<>();result.setCode(200);result.setMsg("成功");result.setData(data);return result;}public static <T> Result<T> error() {Result<T> result = new Result<>();result.setCode(500);result.setMsg("失败");return result;}public static <T> Result<T> error(Integer code, String msg) {Result<T> result = new Result<>();result.setCode(code);result.setMsg(msg);return result;}public static void main(String[] args) {Result error = ResultUtil.error().addData("a", "aaaa", "b", LocalDateTime.now(), "c", true);System.out.println(error);//ResultBean res = ResultBeanUtil.success(DataUtil.build(UserVO.class));//System.out.println(res);}
}

druid数据源代理配置

MyBatis版本

@Configuration
public class DataSourceProxyConfig {@Bean@ConfigurationProperties(prefix = "spring.datasource")public DataSource druidDataSource() {DruidDataSource druidDataSource = new DruidDataSource();return druidDataSource;}@Beanpublic SqlSessionFactory sqlSessionFactory(DataSource dataSource) throws Exception {SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();factoryBean.setDataSource(dataSource);factoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources("classpath*:/mapper/*.xml"));return factoryBean.getObject();}
}

MyBatisPlus版本

@Configuration
public class DataSourceProxyConfig {@Bean@ConfigurationProperties(prefix = "spring.datasource.druid")public DataSource druidDataSource() {DruidDataSource druidDataSource = new DruidDataSource();return druidDataSource;}
}

在2.2.0.RELEASE及以后，数据源代理自动实现了，不需要再手动去配置一个代理类。

seata-account-3001

第一步；创建项目，添加依赖，修改application.yml文件：

server:port: 3001servlet:context-path: /seataspring:application:name: seata-account-3001#配置数据源datasource:type: com.alibaba.druid.pool.DruidDataSourcedruid:driver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://127.0.0.1:3306/seata_account?useSSL=false&serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=UTF8&autoReconnect=true&failOverReadOnly=falseusername: rootpassword: root# 连接池的配置信息:初始化大小，最小，最大initial-size: 8min-idle: 1max-active: 20# 配置获取连接等待超时的时间max-wait: 60000# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒time-between-eviction-runs-millis: 60000# 配置一个连接在池中最小生存的时间，单位是毫秒min-evictable-idle-time-millis: 300000#验证库是否正常sqlvalidation-query: select 'x' from dual#空闲时验证，防止连接断开test-while-idle: truetest-on-borrow: falsetest-on-return: false# 打开PSCache，并且指定每个连接上PSCache的大小pool-prepared-statements: truemax-open-prepared-statements: 20max-pool-prepared-statement-per-connection-size: 20# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙filters: stat,wall,slf4j# 通过connectProperties属性来打开mergeSql功能；慢SQL记录connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000# 合并多个DruidDataSource的监控数据use-global-data-source-stat: truecloud:nacos:discovery:server-addr: 127.0.0.1:8848 # 配置nacos地址sentinel:transport:# 配置sentinel dashboard地址dashboard: 127.0.0.1:8080# 默认端口8719，假如被占用会自动从8719开始依次+1扫描，直至找到未被占用的端口port: 8719config:import:- optional:nacos:seata-client-demo.ymlseata:service:vgroup-mapping:default_tx_group: defaultgrouplist:default: 127.0.0.1:8091management:endpoints:web:exposure:include: '*' #暴露出所有的端点#MyBatisPlus相关配置
mybatis-plus:#mapper映射文件位置，多个目录用逗号或者分号分隔（告诉 Mapper 所对应的 XML 文件位置）mapper-locations: classpath:mapper/*.xml#实体扫描，多个package用逗号或者分号分隔typeAliasesPackage: com.seata.account.domain#  以下配置均有默认值,可以不设置global-config:db-config:#主键类型id-type: autotable-underline: true#数据库大写下划线转换capital-mode: trueconfiguration:# 是否开启自动驼峰命名规则映射:从数据库列名到Java属性驼峰命名的类似映射map-underscore-to-camel-case: truecache-enabled: false#配置JdbcTypeForNulljdbc-type-for-null: 'null'# 如果查询结果中包含空值的列，则 MyBatis 在映射的时候，不会映射这个字段call-setters-on-nulls: true# 将执行的sql打印出来，在开发或测试的时候可以用log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

第二步：项目主启动类：

@EnableDiscoveryClient
@SpringBootApplication
public class SeataAccountApplication {public static void main(String[] args) {SpringApplication.run(SeataAccountApplication.class, args);}
}

第三步：利用MyBatisCodeHelperPro生成Account表对应的实体类、Mapper、Service代码。

第四步：控制器AccountController

@RestController
@RequestMapping("/account")
public class AccountController {@Resourceprivate AccountService accountService;@PostMapping("/decrease")Result decrease(@RequestParam("userId") Long userId, @RequestParam("money") BigDecimal money) {//模拟异常，全局事务回滚// System.out.println(3/0);      //--------------------①accountService.update(Wrappers.<Account>lambdaUpdate().eq(Account::getId, userId).setSql("used = used + " + money));return ResultUtil.success().setMsg("扣款成功");}
}

启动项目，在Nacos中会看到：

post方式请求：http://localhost:3001/seata/account/decrease?userId=1&money=15
能够正常访问。

seata-storage-4001

第一步；创建项目，添加依赖，修改application.yml文件：

server:port: 4001servlet:context-path: /seataspring:application:name: seata-storage-4001#配置数据源datasource:type: com.alibaba.druid.pool.DruidDataSourcedruid:driver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://127.0.0.1:3306/seata_storage?useSSL=false&serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=UTF8&autoReconnect=true&failOverReadOnly=falseusername: rootpassword: root# 连接池的配置信息:初始化大小，最小，最大initial-size: 8min-idle: 1max-active: 20# 配置获取连接等待超时的时间max-wait: 60000# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒time-between-eviction-runs-millis: 60000# 配置一个连接在池中最小生存的时间，单位是毫秒min-evictable-idle-time-millis: 300000#验证库是否正常sqlvalidation-query: select 'x' from dual#空闲时验证，防止连接断开test-while-idle: truetest-on-borrow: falsetest-on-return: false# 打开PSCache，并且指定每个连接上PSCache的大小pool-prepared-statements: truemax-open-prepared-statements: 20max-pool-prepared-statement-per-connection-size: 20# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙filters: stat,wall,slf4j# 通过connectProperties属性来打开mergeSql功能；慢SQL记录connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000# 合并多个DruidDataSource的监控数据use-global-data-source-stat: truecloud:nacos:discovery:server-addr: 127.0.0.1:8848 # 配置nacos地址sentinel:transport:# 配置sentinel dashboard地址dashboard: 127.0.0.1:8080# 默认端口8719，假如被占用会自动从8719开始依次+1扫描，直至找到未被占用的端口port: 8719config:import:- optional:nacos:seata-client-demo.ymlseata:service:vgroup-mapping:default_tx_group: defaultgrouplist:default: 127.0.0.1:8091management:endpoints:web:exposure:include: '*' #暴露出所有的端点#MyBatisPlus相关配置
mybatis-plus:#mapper映射文件位置，多个目录用逗号或者分号分隔（告诉 Mapper 所对应的 XML 文件位置）mapper-locations: classpath:mapper/*.xml#实体扫描，多个package用逗号或者分号分隔typeAliasesPackage: com.seata.storage.domain#  以下配置均有默认值,可以不设置global-config:db-config:#主键类型id-type: autotable-underline: true#数据库大写下划线转换capital-mode: trueconfiguration:# 是否开启自动驼峰命名规则映射:从数据库列名到Java属性驼峰命名的类似映射map-underscore-to-camel-case: truecache-enabled: false#配置JdbcTypeForNulljdbc-type-for-null: 'null'# 如果查询结果中包含空值的列，则 MyBatis 在映射的时候，不会映射这个字段call-setters-on-nulls: true# 将执行的sql打印出来，在开发或测试的时候可以用log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

第二步：项目主启动类添加注解

@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)//取消数据源自动创建
public class SeataStorageApplication {public static void main(String[] args) {SpringApplication.run(SeataStorageApplication.class, args);}
}

第三步：利用MyBatisCodeHelperPro生成Storage表对应的实体类、Mapper、Service代码。

第四步：控制器StorageController

@RestController
@RequestMapping("/storage")
public class StorageController {@Resourceprivate StorageService storageService;@PostMapping("/decrease")Result decrease(@RequestParam("skuId") Long skuId, @RequestParam("count") Integer count) {storageService.update(Wrappers.<Storage>lambdaUpdate().eq(Storage::getSkuId, skuId).setSql("used= used+" + count));return ResultUtil.success().setMsg("库存扣减成功");}
}

启动项目，在Nacos中会看到：

post方式请求：http://localhost:4001/seata/storage/decrease?skuId=1&money=3
能够正常访问。

seata-order-5001

第一步；创建项目，添加依赖，修改application.yml文件：

server:port: 5001servlet:context-path: /seataspring:application:name: seata-order-5001#配置数据源datasource:type: com.alibaba.druid.pool.DruidDataSourcedruid:driver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://127.0.0.1:3306/seata_order?useSSL=false&serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=UTF8&autoReconnect=true&failOverReadOnly=falseusername: rootpassword: root# 连接池的配置信息:初始化大小，最小，最大initial-size: 8min-idle: 1max-active: 20# 配置获取连接等待超时的时间max-wait: 60000# 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒time-between-eviction-runs-millis: 60000# 配置一个连接在池中最小生存的时间，单位是毫秒min-evictable-idle-time-millis: 300000#验证库是否正常sqlvalidation-query: select 'x' from dual#空闲时验证，防止连接断开test-while-idle: truetest-on-borrow: falsetest-on-return: false# 打开PSCache，并且指定每个连接上PSCache的大小pool-prepared-statements: truemax-open-prepared-statements: 20max-pool-prepared-statement-per-connection-size: 20# 配置监控统计拦截的filters，去掉后监控界面sql无法统计，'wall'用于防火墙filters: stat,wall,slf4j# 通过connectProperties属性来打开mergeSql功能；慢SQL记录connection-properties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000# 合并多个DruidDataSource的监控数据use-global-data-source-stat: truecloud:nacos:discovery:server-addr: 127.0.0.1:8848 # 配置nacos地址sentinel:transport:# 配置sentinel dashboard地址dashboard: 127.0.0.1:8080# 默认端口8719，假如被占用会自动从8719开始依次+1扫描，直至找到未被占用的端口port: 8719config:import:- optional:nacos:seata-client-demo.ymlseata:service:vgroup-mapping:default_tx_group: defaultgrouplist:default: 127.0.0.1:8091management:endpoints:web:exposure:include: '*' #暴露出所有的端点#MyBatisPlus相关配置
mybatis-plus:#mapper映射文件位置，多个目录用逗号或者分号分隔（告诉 Mapper 所对应的 XML 文件位置）mapper-locations: classpath:mapper/*.xml#实体扫描，多个package用逗号或者分号分隔typeAliasesPackage: com.seata.order.domain#  以下配置均有默认值,可以不设置global-config:db-config:#主键类型id-type: autotable-underline: true#数据库大写下划线转换capital-mode: trueconfiguration:# 是否开启自动驼峰命名规则映射:从数据库列名到Java属性驼峰命名的类似映射map-underscore-to-camel-case: truecache-enabled: false#配置JdbcTypeForNulljdbc-type-for-null: 'null'# 如果查询结果中包含空值的列，则 MyBatis 在映射的时候，不会映射这个字段call-setters-on-nulls: true# 将执行的sql打印出来，在开发或测试的时候可以用log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

第二步：项目主启动类上添加注解：

@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)//取消数据源自动创建
public class SeataOrderApplication {public static void main(String[] args) {SpringApplication.run(SeataOrderApplication.class, args);}
}

第三步：利用MyBatisCodeHelperPro生成Order表对应的实体类、Mapper、Service代码。

第四步：在feign包下创建：

AccountFeignService.java

@FeignClient(name = "seata-account-3001", path = "/seata")
@RequestMapping("/account")
public interface AccountFeignService {/*** 将skuId对应的商品的库存减少count* @param userId* @param money* @return*/@PostMapping("/decrease")Result decrease(@RequestParam("userId") Long userId, @RequestParam("money") BigDecimal money);
}

StorageFeignService.java

@FeignClient(name = "seata-storage-4001", path = "/seata")
@RequestMapping("/storage")
public interface StorageFeignService {/*** 将skuId对应的商品的库存减少count* @param skuId* @param count* @return*/@PostMapping("/decrease")Result decrease(@RequestParam("skuId") Long skuId, @RequestParam("count") Integer count);
}

第五步：修改OrderServiceImpl的代码如下所示：

@Service
public class OrderServiceImpl extends ServiceImpl<OrderMapper, Order> implements OrderService {@Resourceprivate OrderMapper orderMapper;@Resourceprivate StorageFeignService storageFeignService;@Resourceprivate AccountFeignService accountFeignService;@Override//  @GlobalTransactional(rollbackFor = Exception.class)  //全局异常   //----------------②public void create(Order order) {System.out.println("user建订单");orderMapper.insert(order);System.out.println("扣减库存");storageFeignService.decrease(order.getSkuId(),order.getCount());System.out.println("账户余额扣减");accountFeignService.decrease(order.getUserId(),order.getMoney());System.out.println("修改订单的状态");//1表示完成状态orderMapper.updateStateByUserId(order.getUserId(),1);System.out.println("下单结束");}
}

第六步：控制器OrderController

@RestController
@RequestMapping("/order")
public class OrderController {@Resourceprivate OrderService orderService;@GetMapping("/create")public Result create(Order order){orderService.create(order);return ResultUtil.success().setMsg("下单成功！");}
}

启动项目：

测试

url：http://localhost:5001/seata/order/create?userId=1&skuId=1&count=10&money=30

保持编号①和编号②处于注释状态：请求url，tb_order表增加了一条记录，用户账户用掉30，库存用掉10。
保持编号②处于注释状态，去掉编号①前的注释：请求url，tb_order表增加了一条记录但状态值为null，用户账户没有发生变化，库存用掉10。没有能够保证数据的完整性
去掉编号①和编号②前的注释：请求url，三个表的数据都没有发生变化。

结论：
微服务中使用alibaba的seata技术实现全局事务控制只需要在相应的Service实现类中添加@GlobalTransactional注解就可以了。