1、Seata简介
- Seata是一款开源的分布式事务解决方案，致力于在微服务架构下提供高性能和简单易用的分布式事务服务
- http://seata.io/zh-cn/
- 分布式事务处理过程 唯一ID+三大组件模型
- Transaction ID XID:全局唯一ID
- Transaction Coordinator(TC):事务协调器，维护全局事务的运行状态，负责协调并驱动全局事务的提交或回滚
- Transaction Manager(TM):控制全局事务的边界，负责开启一个全局事务，并最终发起全局提交或全局回滚的决议
- Resource Manager(RM):控制分支事务，服务分支注册、状态汇报、并接收事务协调的指令，驱动分支（本地）事务的提交和回滚
- 处理过程
- TM向TC申请开启一个全局事务，全局事务创建成功并生成一个全局唯一的XID
- XID在微服务调用链路的上下文中传播
- RM向TC注册分支事务，将其纳入XID对应全局事务的管辖
- TM向TC发起针对XID的全局提交或回滚决议
- TC调度XID下管辖的全部分支事务完成提交或回滚请求
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2、安装
- 官网下载seata到本地，解压
- 修改conf目录下的file.conf配置文件
- 自定义事务组名称
- 修改store mode = "db"
- 修改连接数据的账号密码
- mysql新建数据库seata
- 执行 db_store.sql 文件
- 修改conf目录下registry.conf配置文件，指明注册中心为nacos,即修改nacos连接信息
- 先启动nacos,再启动seata
3、业务数据库
-
创建三个服务，一个订单服务，一个库存服务，一个账号服务
- 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扣减用户账户里面的余额
- 最后在订单服务中修改订单状态已完成
-
该操作跨越三个数据库，有两次远程调用，会有分布式事务问题
-
创建业务数据库
- seata_order:存储订单的数据库
- seata_storage:存储库存的数据库
- seata_account:存储账户信息的数据库
-
按照上述3库分别建立对应业务表
-
按照上述3库分别建立对应的回滚日志表 sql文件 db_undo_log.sql
4、order订单服务
- 新建seata-order-service2001
- maven依赖
<dependencies>
<!--nacos-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<!--seata-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-seata</artifactId>
<exclusions>
<exclusion>
<artifactId>seata-all</artifactId>
<groupId>io.seata</groupId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.seata</groupId>
<artifactId>seata-all</artifactId>
<version>0.9.0</version>
</dependency>
<!--feign-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<!--web-actuator-->
<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>
<!--mysql-druid-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.37</version>
</dependency>
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>druid-spring-boot-starter</artifactId>
<version>1.1.10</version>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>2.0.0</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
</dependencies>
- yml
server:
port: 2001
spring:
application:
name: seata-order-service
cloud:
alibaba:
seata:
tx-service-group: fsp_tx_group
nacos:
discovery:
server-addr: localhost:8848
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/seata_order
username: root
password: 1
logging:
level:
io:
seata: info
mybatis:
mapperLocations: classpath:mapper/*.xml
- controller
@RestController
public class OrderController {
@Autowired
private OrderService orderService;
/**
* 创建订单
*/
@GetMapping("/order/create")
public CommonResult create(Order order) {
System.out.println("-------------------->");
orderService.create(order);
return new CommonResult(200, "订单创建成功!");
}
}
- serivce
@Service
@Slf4j
public class OrderServiceImpl implements OrderService
{
@Autowired
private OrderDao orderDao;
@Autowired
private StorageService storageService;
@Autowired
private AccountService accountService;
/**
* 创建订单->调用库存服务扣减库存->调用账户服务扣减账户余额->修改订单状态
* 简单说：
* 下订单->减库存->减余额->改状态
*/
@Override
@GlobalTransactional(name = "fsp-create-order",rollbackFor = Exception.class)
public void create(Order order) {
log.info("------->下单开始");
//本应用创建订单
orderDao.create(order);
//远程调用库存服务扣减库存
log.info("------->order-service中扣减库存开始");
storageService.decrease(order.getProductId(),order.getCount());
log.info("------->order-service中扣减库存结束");
//远程调用账户服务扣减余额
log.info("------->order-service中扣减余额开始");
accountService.decrease(order.getUserId(),order.getMoney());
log.info("------->order-service中扣减余额结束");
//修改订单状态为已完成
log.info("------->order-service中修改订单状态开始");
orderDao.update(order.getUserId(),0);
log.info("------->order-service中修改订单状态结束");
log.info("------->下单结束");
}
}
- 在resources中添加file.conf，registry.conf文件
- config
@Configuration
public class DataSourceProxyConfig {
@Value("${mybatis.mapperLocations}")
private String mapperLocations;
@Bean
@ConfigurationProperties(prefix = "spring.datasource")
public DataSource druidDataSource(){
return new DruidDataSource();
}
@Bean
public DataSourceProxy dataSourceProxy(DataSource dataSource) {
return new DataSourceProxy(dataSource);
}
@Bean
public SqlSessionFactory sqlSessionFactoryBean(DataSourceProxy dataSourceProxy) throws Exception {
SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
sqlSessionFactoryBean.setDataSource(dataSourceProxy);
sqlSessionFactoryBean.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(mapperLocations));
sqlSessionFactoryBean.setTransactionFactory(new SpringManagedTransactionFactory());
return sqlSessionFactoryBean.getObject();
}
}
- 启动类
@EnableDiscoveryClient
@EnableFeignClients
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class) //取消数据源的自动创建
@MapperScan({"com.atguigu.springcloud.dao"})
public class OrderMain2001 {
public static void main(String[] args)
{
SpringApplication.run(OrderMain2001.class, args);
}
}