- 业务说明
:这里我们创建三个服务,一个订单服务,一个库存服务,一个账户服务
。- 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来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为已完成。该操作跨越三个数据库,有两次远程调用,很明显会有分布式事务问题
6.1.数据库表准备
a.建三个数据库
CREATE DATABASE seata_order;
CREATE DATABASE seata_storage;
CREATE DATABASE seata_account;
b.undo_log回滚日志表
- 1.
按照上述的3个数据库分别对应的undo_log回滚日志表
: - 2.seata官网
- 3.undo_log建表SQL如下:
AT模式专用的,其他模式都不需要
-- for AT mode you must to init this sql for you business database. the seata server not need it.
CREATE TABLE IF NOT EXISTS `undo_log`
(`branch_id` BIGINT NOT NULL COMMENT 'branch transaction id',`xid` VARCHAR(128) NOT NULL COMMENT 'global transaction id',`context` VARCHAR(128) NOT NULL COMMENT 'undo_log context,such as serialization',`rollback_info` LONGBLOB NOT NULL COMMENT 'rollback info',`log_status` INT(11) NOT NULL COMMENT '0:normal status,1:defense status',`log_created` DATETIME(6) NOT NULL COMMENT 'create datetime',`log_modified` DATETIME(6) NOT NULL COMMENT 'modify datetime',UNIQUE KEY `ux_undo_log` (`xid`, `branch_id`)
) ENGINE = InnoDB AUTO_INCREMENT = 1 DEFAULT CHARSET = utf8mb4 COMMENT ='AT transaction mode undo table';
ALTER TABLE `undo_log` ADD INDEX `ix_log_created` (`log_created`);
c.按照3个库分别对应业务表:
CREATE TABLE t_order(
`id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
`user_id` BIGINT(11) DEFAULT NULL COMMENT '用户id',
`product_id` BIGINT(11)DEFAULT NULL COMMENT '产品id',
`count` INT(11) DEFAULT NULL COMMENT '数量',
`money` DECIMAL(11,0) DEFAULT NULL COMMENT '金额',
`status` INT(1) DEFAULT NULL COMMENT '订单状态: 0:创建中; 1:已完结'
)ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
SELECT * FROM t_order;
CREATE TABLE t_account(
`id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'id',
`user_id` BIGINT(11) DEFAULT NULL COMMENT '用户id',
`total` DECIMAL(10,0) DEFAULT NULL COMMENT '总额度',
`used` DECIMAL(10,0) DEFAULT NULL COMMENT '已用账户余额',
`residue` DECIMAL(10,0) DEFAULT '0' COMMENT '剩余可用额度'
)ENGINE=INNODB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
INSERT INTO t_account(`id`,`user_id`,`total`,`used`,`residue`)VALUES('1','1','1000','0','1000');
SELECT * FROM t_account;
CREATE TABLE t_storage(
`id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,
`product_id` BIGINT(11) DEFAULT NULL COMMENT '产品id',
`total` INT(11) DEFAULT NULL COMMENT '总库存',
`used` INT(11) DEFAULT NULL COMMENT '已用库存',
`residue` INT(11) DEFAULT NULL COMMENT '剩余库存'
)ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;INSERT INTO t_storage(`id`,`product_id`,`total`,`used`,`residue`)VALUES('1','1','100','0','100');SELECT * FROM t_storage;
d.最终的效果:
库表图:
所有的SQL:
- 1.建seata_order库 + 建t_order表 + undo_log表:
#orderCREATE DATABASE seata_order;USE seata_order;CREATE TABLE t_order(`id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,`user_id` BIGINT(11) DEFAULT NULL COMMENT '用户id',`product_id` BIGINT(11)DEFAULT NULL COMMENT '产品id',`count` INT(11) DEFAULT NULL COMMENT '数量',`money` DECIMAL(11,0) DEFAULT NULL COMMENT '金额',`status` INT(1) DEFAULT NULL COMMENT '订单状态: 0:创建中; 1:已完结')ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;SELECT * FROM t_order;-- for AT mode you must to init this sql for you business database. the seata server not need it.CREATE TABLE IF NOT EXISTS `undo_log`(`branch_id` BIGINT NOT NULL COMMENT 'branch transaction id',`xid` VARCHAR(128) NOT NULL COMMENT 'global transaction id',`context` VARCHAR(128) NOT NULL COMMENT 'undo_log context,such as serialization',`rollback_info` LONGBLOB NOT NULL COMMENT 'rollback info',`log_status` INT(11) NOT NULL COMMENT '0:normal status,1:defense status',`log_created` DATETIME(6) NOT NULL COMMENT 'create datetime',`log_modified` DATETIME(6) NOT NULL COMMENT 'modify datetime',UNIQUE KEY `ux_undo_log` (`xid`, `branch_id`)) ENGINE = InnoDB AUTO_INCREMENT = 1 DEFAULT CHARSET = utf8mb4 COMMENT ='AT transaction mode undo table';ALTER TABLE `undo_log` ADD INDEX `ix_log_created` (`log_created`);
- 2.建seata_storage库 + 建t_storage表 + undo_log表:
#storageCREATE DATABASE seata_storage;USE seata_storage;CREATE TABLE t_storage(`id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,`product_id` BIGINT(11) DEFAULT NULL COMMENT '产品id',`total` INT(11) DEFAULT NULL COMMENT '总库存',`used` INT(11) DEFAULT NULL COMMENT '已用库存',`residue` INT(11) DEFAULT NULL COMMENT '剩余库存')ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;INSERT INTO t_storage(`id`,`product_id`,`total`,`used`,`residue`)VALUES('1','1','100','0','100');SELECT * FROM t_storage;-- for AT mode you must to init this sql for you business database. the seata server not need it.CREATE TABLE IF NOT EXISTS `undo_log`(`branch_id` BIGINT NOT NULL COMMENT 'branch transaction id',`xid` VARCHAR(128) NOT NULL COMMENT 'global transaction id',`context` VARCHAR(128) NOT NULL COMMENT 'undo_log context,such as serialization',`rollback_info` LONGBLOB NOT NULL COMMENT 'rollback info',`log_status` INT(11) NOT NULL COMMENT '0:normal status,1:defense status',`log_created` DATETIME(6) NOT NULL COMMENT 'create datetime',`log_modified` DATETIME(6) NOT NULL COMMENT 'modify datetime',UNIQUE KEY `ux_undo_log` (`xid`, `branch_id`)) ENGINE = InnoDB AUTO_INCREMENT = 1 DEFAULT CHARSET = utf8mb4 COMMENT ='AT transaction mode undo table';ALTER TABLE `undo_log` ADD INDEX `ix_log_created` (`log_created`);
- 3.建seata_account库 + 建t_account表 + undo_log表:
#accountcreate database seata_account;use seata_account;CREATE TABLE t_account(`id` BIGINT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY COMMENT 'id',`user_id` BIGINT(11) DEFAULT NULL COMMENT '用户id',`total` DECIMAL(10,0) DEFAULT NULL COMMENT '总额度',`used` DECIMAL(10,0) DEFAULT NULL COMMENT '已用余额',`residue` DECIMAL(10,0) DEFAULT '0' COMMENT '剩余可用额度')ENGINE=INNODB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;INSERT INTO t_account(`id`,`user_id`,`total`,`used`,`residue`)VALUES('1','1','1000','0','1000');SELECT * FROM t_account;-- for AT mode you must to init this sql for you business database. the seata server not need it.CREATE TABLE IF NOT EXISTS `undo_log`(`branch_id` BIGINT NOT NULL COMMENT 'branch transaction id',`xid` VARCHAR(128) NOT NULL COMMENT 'global transaction id',`context` VARCHAR(128) NOT NULL COMMENT 'undo_log context,such as serialization',`rollback_info` LONGBLOB NOT NULL COMMENT 'rollback info',`log_status` INT(11) NOT NULL COMMENT '0:normal status,1:defense status',`log_created` DATETIME(6) NOT NULL COMMENT 'create datetime',`log_modified` DATETIME(6) NOT NULL COMMENT 'modify datetime',UNIQUE KEY `ux_undo_log` (`xid`, `branch_id`)) ENGINE = InnoDB AUTO_INCREMENT = 1 DEFAULT CHARSET = utf8mb4 COMMENT ='AT transaction mode undo table';ALTER TABLE `undo_log` ADD INDEX `ix_log_created` (`log_created`);
6.2.微服务编码和落地实现:
整个业务流程:
下订单 -> 减库存 ->扣余额 -> 改订单状态
a.MyBatis一键生成:
config.properties
#t_pay表包名
package.name=com.atguigu.cloud# mysql8.0
jdbc.driverClass = com.mysql.cj.jdbc.Driver
jdbc.url= jdbc:mysql://localhost:3306/db2024?characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8&rewriteBatchedStatements=true&allowPublicKeyRetrieval=true
jdbc.user = root
jdbc.password =123456# seata_order
#jdbc.driverClass = com.mysql.cj.jdbc.Driver
#jdbc.url = jdbc:mysql://localhost:3306/seata_order?characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8&rewriteBatchedStatements=true&allowPublicKeyRetrieval=true
#jdbc.user = root
#jdbc.password =123456# seata_storage
#jdbc.driverClass = com.mysql.cj.jdbc.Driver
#jdbc.url = jdbc:mysql://localhost:3306/seata_storage?characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8&rewriteBatchedStatements=true&allowPublicKeyRetrieval=true
#jdbc.user = root
#jdbc.password =123456# seata_account
#jdbc.driverClass = com.mysql.cj.jdbc.Driver
#jdbc.url = jdbc:mysql://localhost:3306/seata_account?characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8&rewriteBatchedStatements=true&allowPublicKeyRetrieval=true
#jdbc.user = root
#jdbc.password =123456
generatorConfig.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfigurationPUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN""http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd"><generatorConfiguration><properties resource="config.properties"/><context id="Mysql" targetRuntime="MyBatis3Simple" defaultModelType="flat"><property name="beginningDelimiter" value="`"/><property name="endingDelimiter" value="`"/><plugin type="tk.mybatis.mapper.generator.MapperPlugin"><property name="mappers" value="tk.mybatis.mapper.common.Mapper"/><property name="caseSensitive" value="true"/></plugin><jdbcConnection driverClass="${jdbc.driverClass}"connectionURL="${jdbc.url}"userId="${jdbc.user}"password="${jdbc.password}"></jdbcConnection><javaModelGenerator targetPackage="${package.name}.entities" targetProject="src/main/java"/><sqlMapGenerator targetPackage="${package.name}.mapper" targetProject="src/main/java"/><javaClientGenerator targetPackage="${package.name}.mapper" targetProject="src/main/java" type="XMLMAPPER"/><table tableName="t_pay" domainObjectName="Pay"><generatedKey column="id" sqlStatement="JDBC"/></table><!-- seata_order --><!--<table tableName="t_order" domainObjectName="Order"><generatedKey column="id" sqlStatement="JDBC"/></table>--><!--seata_storage--><!--<table tableName="t_storage" domainObjectName="Storage"><generatedKey column="id" sqlStatement="JDBC"/></table>--><!--seata_account--><!--<table tableName="t_account" domainObjectName="Account"><generatedKey column="id" sqlStatement="JDBC"/></table>--></context>
</generatorConfiguration>
b.修改公共cloud-api-commons模块:
新增库存和账户两个Feign服务接口
- 1.StorageFeignApi.java
package com.atguigu.cloud.apis;
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);
}
- 2.AccountFeignApi.java
package com.atguigu.cloud.apis;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 17:42*/
@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);
}