SpringCloud Alibaba-05 Seata分布式事务处理

在这里插入图片描述

一次业务操作需要跨多个数据源或需要跨多个系统进行远程调用，就会产生分布式事务问题。但是关系型数据库提供的能力是基于单机事务的，一旦遇到分布式事务场景，就需要通过更多其他技术手段来解决问题。

在这里插入图片描述

在这里插入图片描述

1.四大模式： Seata AT模式(主流) Seata TCC模式 Seata Saga模式 Seata XA模式

2.安装
2.1 建立一个seata数据库，执行脚本创建表

-- -------------------------------- 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_status_gmt_modified` (`status` , `gmt_modified`),KEY `idx_transaction_id` (`transaction_id`)
) ENGINE = InnoDBDEFAULT CHARSET = utf8mb4;
-- 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 = InnoDBDEFAULT CHARSET = utf8mb4;
-- 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),`status`         TINYINT      NOT NULL DEFAULT '0' COMMENT '0:locked ,1:rollbacking',`gmt_create`     DATETIME,`gmt_modified`   DATETIME,PRIMARY KEY (`row_key`),KEY `idx_status` (`status`),KEY `idx_branch_id` (`branch_id`),KEY `idx_xid` (`xid`)
) ENGINE = InnoDBDEFAULT CHARSET = utf8mb4;
CREATE TABLE IF NOT EXISTS `distributed_lock`
(`lock_key`       CHAR(20) NOT NULL,`lock_value`     VARCHAR(20) NOT NULL,`expire`         BIGINT,primary key (`lock_key`)
) ENGINE = InnoDBDEFAULT CHARSET = utf8mb4;
INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('AsyncCommitting', ' ', 0);
INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('RetryCommitting', ' ', 0);
INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('RetryRollbacking', ' ', 0);
INSERT INTO `distributed_lock` (lock_key, lock_value, expire) VALUES ('TxTimeoutCheck', ' ', 0);

在这里插入图片描述
2.2 配置application.yml

seata:config:type: nacosnacos:server-addr: 127.0.0.1:8848namespace:group: SEATA_GROUP #后续自己在nacos里面新建,不想新建SEATA_GROUP，就写DEFAULT_GROUPusername: nacospassword: nacosregistry:type: nacosnacos:application: seata-serverserver-addr: 127.0.0.1:8848group: SEATA_GROUP #后续自己在nacos里面新建,不想新建SEATA_GROUP，就写DEFAULT_GROUPnamespace:cluster: defaultusername: nacospassword: nacos    store:mode: dbdb:datasource: druiddb-type: mysqldriver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/seata?characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8&rewriteBatchedStatements=true&allowPublicKeyRetrieval=trueuser: rootpassword: dc123min-conn: 10max-conn: 100global-table: global_tablebranch-table: branch_tablelock-table: lock_tabledistributed-lock-table: distributed_lockquery-limit: 1000max-wait: 5000

2.3 启动nacos和seata
seata启动：在bin目录下打开cmd 执行 seata-server.bat 命令
登录http://localhost:7091 账户密码都是: seata

3.实战模拟
3.1 建立订单库存账户三个数据库

3.2 MybatisX生成代码

3.3 在cloud-api-commons新建接口 StorageFeignApi 和 AccountFeignApi

import com.atguigu.cloud.resp.ResultData;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;/*** @auther zzyy* @create 2023-12-01 17:41*/
@FeignClient(value = "seata-storage-service")
public interface StorageFeignApi
{/*** 扣减库存*/@PostMapping(value = "/storage/decrease")ResultData decrease(@RequestParam("productId") Long productId, @RequestParam("count") Integer count);
}

@FeignClient(value = "seata-account-service")
public interface AccountFeignApi
{//扣减账户余额@PostMapping("/account/decrease")ResultData decrease(@RequestParam("userId") Long userId, @RequestParam("money") Long money);
}

4.新建Order微服务
3.1 建Modul,改pom

    <dependencies><!-- nacos --><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId></dependency><!--alibaba-seata--><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-seata</artifactId></dependency><!--openfeign--><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-openfeign</artifactId></dependency><!--loadbalancer--><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-loadbalancer</artifactId></dependency><!--cloud-api-commons--><dependency><groupId>com.dc.cloud</groupId><artifactId>cloud-api-commons</artifactId><version>1.0-SNAPSHOT</version></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><!--SpringBoot集成druid连接池--><dependency><groupId>com.alibaba</groupId><artifactId>druid-spring-boot-starter</artifactId></dependency><!-- Swagger3 调用方式 http://你的主机IP地址:5555/swagger-ui/index.html --><dependency><groupId>org.springdoc</groupId><artifactId>springdoc-openapi-starter-webmvc-ui</artifactId></dependency><!--mybatis和springboot整合--><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId></dependency><!--Mysql数据库驱动8 --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId></dependency><!--persistence--><dependency><groupId>javax.persistence</groupId><artifactId>persistence-api</artifactId></dependency><!--通用Mapper4--><dependency><groupId>tk.mybatis</groupId><artifactId>mapper</artifactId></dependency><!--hutool--><dependency><groupId>cn.hutool</groupId><artifactId>hutool-all</artifactId></dependency><!-- fastjson2 --><dependency><groupId>com.alibaba.fastjson2</groupId><artifactId>fastjson2</artifactId></dependency><!--lombok--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.28</version><scope>provided</scope></dependency><!--test--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId></plugin></plugins></build>
</project>

3.2 改yml

server:port: 2001spring:application:name: seata-order-servicecloud:nacos:discovery:server-addr: localhost:8848         #Nacos服务注册中心地址
# ==========applicationName + druid-mysql8 driver===================datasource:type: com.alibaba.druid.pool.DruidDataSourcedriver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/seata_order?characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8&rewriteBatchedStatements=true&allowPublicKeyRetrieval=trueusername: rootpassword: root
# ========================mybatis===================
mybatis:mapper-locations: classpath:mapper/*.xmltype-aliases-package: com.atguigu.cloud.entitiesconfiguration:map-underscore-to-camel-case: true# ========================seata===================
seata:registry:type: nacosnacos:server-addr: 127.0.0.1:8848namespace: ""group: SEATA_GROUPapplication: seata-servertx-service-group: default_tx_group # 事务组，由它获得TC服务的集群名称service:vgroup-mapping: # 点击源码分析default_tx_group: default # 事务组与TC服务集群的映射关系data-source-proxy-mode: ATlogging:level:io:seata: info

3.3 主启动

@SpringBootApplication
@MapperScan("com.dc.cloud.mapper") //import tk.mybatis.spring.annotation.MapperScan;
@EnableDiscoveryClient //服务注册和发现
@EnableFeignClients
public class SeataOrderMainApp2001
{public static void main(String[] args){SpringApplication.run(SeataOrderMainApp2001.class,args);}
}

3.4 业务类

@Slf4j
@Service
public class OrderServiceImpl implements OrderService
{@Resourceprivate OrderMapper orderMapper;@Resource//订单微服务通过OpenFeign去调用库存微服务private StorageFeignApi storageFeignApi;@Resource//订单微服务通过OpenFeign去调用账户微服务private AccountFeignApi accountFeignApi;@Override//@GlobalTransactional(name = "DC-create-order",rollbackFor = Exception.class) //AT//@GlobalTransactional @Transactional(rollbackFor = Exception.class) //XApublic void create(Order order) {//Q全局事务id   xid检查String xid = RootContext.getXID();//1. 新建订单log.info("==================>开始新建订单"+"\t"+"xid_order:" +xid);//订单状态status：0：创建中；1：已完结order.setStatus(0);int result = orderMapper.insertSelective(order);//插入订单成功后获得插入mysql的实体对象Order orderFromDB = null;if(result > 0){orderFromDB = orderMapper.selectOne(order);//orderFromDB = orderMapper.selectByPrimaryKey(order.getId());log.info("-------> 新建订单成功，orderFromDB info: "+orderFromDB);System.out.println();//2. 扣减库存log.info("-------> 订单微服务开始调用Storage库存，做扣减count");storageFeignApi.decrease(orderFromDB.getProductId(), orderFromDB.getCount());log.info("-------> 订单微服务结束调用Storage库存，做扣减完成");System.out.println();//3. 扣减账号余额log.info("-------> 订单微服务开始调用Account账号，做扣减money");accountFeignApi.decrease(orderFromDB.getUserId(), orderFromDB.getMoney());log.info("-------> 订单微服务结束调用Account账号，做扣减完成");System.out.println();//4. 修改订单状态//订单状态status：0：创建中；1：已完结log.info("-------> 修改订单状态");orderFromDB.setStatus(1);//类似lambdaquerymapperExample whereCondition=new Example(Order.class);Example.Criteria criteria=whereCondition.createCriteria();criteria.andEqualTo("userId",orderFromDB.getUserId());criteria.andEqualTo("status",0);int updateResult = orderMapper.updateByExampleSelective(orderFromDB, whereCondition);log.info("-------> 修改订单状态完成"+"\t"+updateResult);log.info("-------> orderFromDB info: "+orderFromDB);}System.out.println();log.info("==================>结束新建订单"+"\t"+"xid_order:" +xid);}
}