SpringCloud Alibaba Seata处理分布式事务

分布式事务问题

分布式前

单机库存没这个问题

O(∩_∩)O

从1:1->1:N->N:N

分布式之后

单体应用被拆分成微服务应用，原来的三个模块被拆分成三个独立的应用，分别使用三个独立的数据源,
业务操作需要调用三个服务来完成。此时每个服务内部的数据一致性由本地事务来保证, 但是全局的数据一致性问题没法保证。

一句话

一次业务操作需要垮多个数据源或需要垮多个系统进行远程调用,就会产生分布式事务问题

Seata简介

是什么

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

官网地址

http://seata.io/zh-cn/

能干嘛

一个典型的分布式事务过程

分布式事务处理过程-ID+三组件模型

Transaction ID(XID)

全局唯一的事务id

三组件概念

• 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,负责分支注册、状态汇报,并接受事务协调的指令,驱动分支(本地)事务的提交和回滚

处理过程

在哪下

发布说明: https://github.com/seata/seata/releases

怎么玩

本地@Transational

全局@GlobalTranstional

seata的分布式交易解决方案

Seata-Server安装

1.官网地址

https://seata.io/zh-cn/

2.下载版本

3.seata-server-0.9.0.zip解压到指定目录并修改conf目录下的file.conf配置文件

先备份原始file.conf文件

主要修改:自定义事务组名称+事务日志存储模式为db+数据库连接

file.conf

service模块

store模块

4.mysql5.7数据库新建库seata

5.在seata库里新建表

建表db_store.sql在seata-server-0.9.0\seata\conf目录里面

db_store.sql

SQL

-- the table to store GlobalSession data
drop table if exists `global_table`;
create table `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`)
);
 
-- the table to store BranchSession data
drop table if exists `branch_table`;
create table `branch_table` (
  `branch_id` bigint not null,
  `xid` varchar(128) not null,
  `transaction_id` bigint ,
  `resource_group_id` varchar(32),
  `resource_id` varchar(256) ,
  `lock_key` varchar(128) ,
  `branch_type` varchar(8) ,
  `status` tinyint,
  `client_id` varchar(64),
  `application_data` varchar(2000),
  `gmt_create` datetime,
  `gmt_modified` datetime,
  primary key (`branch_id`),
  key `idx_xid` (`xid`)
);
 
-- the table to store lock data
drop table if exists `lock_table`;
create table `lock_table` (
  `row_key` varchar(128) not null,
  `xid` varchar(96),
  `transaction_id` long ,
  `branch_id` long,
  `resource_id` varchar(256) ,
  `table_name` varchar(32) ,
  `pk` varchar(36) ,
  `gmt_create` datetime ,
  `gmt_modified` datetime,
  primary key(`row_key`)
);

6.修改seata-server-0.9.0\seata\conf目录下的registry.conf目录下的registry.conf配置文件

7.先启动Nacos端口号8848

8.再启动seata-server

seata-server-0.9.0\seata\bin
seata-server.bat

订单/库存/账户业务数据库准备

以下演示都需要先启动Nacos后启动Seata,保证两个都OK

Seata没启动报错no available server to connect

分布式事务业务说明

这里我们会创建三个服务, 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。

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

建表SQL

create database seata_order;
create database seata_storage;
create database seata_account;

按照上述3库分别建立对应业务表

seata_order库下新建t_order表

DROP TABLE IF EXISTS `t_order`;
CREATE TABLE `t_order`  (
  `int` bigint(11) NOT NULL AUTO_INCREMENT,
  `user_id` bigint(20) 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',
  PRIMARY KEY (`int`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = '订单表' ROW_FORMAT = Dynamic;

seata_storage库下新建t_storage表

DROP TABLE IF EXISTS `t_storage`;
CREATE TABLE `t_storage`  (
  `int` bigint(11) NOT NULL AUTO_INCREMENT,
  `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',
  PRIMARY KEY (`int`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = '库存' ROW_FORMAT = Dynamic;
INSERT INTO `t_storage` VALUES (1, 1, 100, 0, 100);

seata_account库下新建t_account表

CREATE TABLE `t_account`  (
  `id` bigint(11) NOT NULL 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 NULL COMMENT '剩余可用额度',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci COMMENT = '账户表' ROW_FORMAT = Dynamic;
 
INSERT INTO `t_account` VALUES (1, 1, 1000, 0, 1000);

按照上述3库分别建立对应的回滚日志表

订单-库存-账户3个库下都需要建各自独立的回滚日志表

seata-server-0.9.0\seata\conf\目录下的db_undo_log.sql

建表SQL

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,
  `ext` varchar(100) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

最终效果

订单/库存/账户业务微服务准备

业务需求

下订单->减库存->扣余额->改(订单)状态

新建订单Order-Module

1.seata-order-service2001

2.POM

<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>
                <groupId>io.seata</groupId>
                <artifactId>seata-all</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>io.seata</groupId>
        <artifactId>seata-all</artifactId>
        <version>0.9.0</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>
    <!--jdbc-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-jdbc</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <!--hutool 测试雪花算法-->
    <dependency>
        <groupId>cn.hutool</groupId>
        <artifactId>hutool-captcha</artifactId>
        <version>5.2.0</version>
    </dependency>
</dependencies>

3.YML

server:
  port: 2001

spring:
  application:
    name: seata-order-service
  cloud:
    alibaba:
      seata:
        # 自定义事务组名称需要与seata-server中的对应
        tx-service-group: fsp_tx_group
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848
  datasource:
    # 当前数据源操作类型
    type: com.alibaba.druid.pool.DruidDataSource
    # mysql驱动类
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/seata_order?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8
    username: root
    password: root
feign:
  hystrix:
    enabled: false
logging:
  level:
    io:
      seata: info

mybatis:
  mapperLocations: classpath*:mapper/*.xml

4.file.conf

就是seata文件夹下的file.conf
拷贝seata-server/conf目录下的file.conf

transport {
  # tcp udt unix-domain-socket
  type = "TCP"
  #NIO NATIVE
  server = "NIO"
  #enable heartbeat
  heartbeat = true
  #thread factory for netty
  thread-factory {
    boss-thread-prefix = "NettyBoss"
    worker-thread-prefix = "NettyServerNIOWorker"
    server-executor-thread-prefix = "NettyServerBizHandler"
    share-boss-worker = false
    client-selector-thread-prefix = "NettyClientSelector"
    client-selector-thread-size = 1
    client-worker-thread-prefix = "NettyClientWorkerThread"
    # netty boss thread size,will not be used for UDT
    boss-thread-size = 1
    #auto default pin or 8
    worker-thread-size = 8
  }
  shutdown {
    # when destroy server, wait seconds
    wait = 3
  }
  serialization = "seata"
  compressor = "none"
}
service {
  #vgroup->rgroup
  # 事务组名称
  vgroup_mapping.fsp_tx_group = "default"
  #only support single node
  default.grouplist = "127.0.0.1:8091"
  #degrade current not support
  enableDegrade = false
  #disable
  disable = false
  #unit ms,s,m,h,d represents milliseconds, seconds, minutes, hours, days, default permanent
  max.commit.retry.timeout = "-1"
  max.rollback.retry.timeout = "-1"
}
 
client {
  async.commit.buffer.limit = 10000
  lock {
    retry.internal = 10
    retry.times = 30
  }
  report.retry.count = 5
  tm.commit.retry.count = 1
  tm.rollback.retry.count = 1
}
 
## transaction log store
store {
  ## store mode: file、db
  #mode = "file"
  mode = "db"
 
  ## file store
  file {
    dir = "sessionStore"
 
    # branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
    max-branch-session-size = 16384
    # globe session size , if exceeded throws exceptions
    max-global-session-size = 512
    # file buffer size , if exceeded allocate new buffer
    file-write-buffer-cache-size = 16384
    # when recover batch read size
    session.reload.read_size = 100
    # async, sync
    flush-disk-mode = async
  }
 
  ## database store
  db {
    ## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp) etc.
    datasource = "dbcp"
    ## mysql/oracle/h2/oceanbase etc.
    db-type = "mysql"
    driver-class-name = "com.mysql.jdbc.Driver"
    url = "jdbc:mysql://127.0.0.1:3306/seata"
    user = "root"
    password = "root"
    min-conn = 1
    max-conn = 3
    global.table = "global_table"
    branch.table = "branch_table"
    lock-table = "lock_table"
    query-limit = 100
  }
}
lock {
  ## the lock store mode: local、remote
  mode = "remote"
 
  local {
    ## store locks in user's database
  }
 
  remote {
    ## store locks in the seata's server
  }
}
recovery {
  #schedule committing retry period in milliseconds
  committing-retry-period = 1000
  #schedule asyn committing retry period in milliseconds
  asyn-committing-retry-period = 1000
  #schedule rollbacking retry period in milliseconds
  rollbacking-retry-period = 1000
  #schedule timeout retry period in milliseconds
  timeout-retry-period = 1000
}
 
transaction {
  undo.data.validation = true
  undo.log.serialization = "jackson"
  undo.log.save.days = 7
  #schedule delete expired undo_log in milliseconds
  undo.log.delete.period = 86400000
  undo.log.table = "undo_log"
}
 
## metrics settings
metrics {
  enabled = false
  registry-type = "compact"
  # multi exporters use comma divided
  exporter-list = "prometheus"
  exporter-prometheus-port = 9898
}
 
support {
  ## spring
  spring {
    # auto proxy the DataSource bean
    datasource.autoproxy = false
  }
}

5.registry.conf

拷贝seata-server/conf目录下的registry.conf

registry {
  # file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
  type = "nacos"
 
  nacos {
    #serverAddr = "localhost"
    serverAddr = "localhost:8848"
    namespace = ""
    cluster = "default"
  }
  eureka {
    serviceUrl = "http://localhost:8761/eureka"
    application = "default"
    weight = "1"
  }
  redis {
    serverAddr = "localhost:6379"
    db = "0"
  }
  zk {
    cluster = "default"
    serverAddr = "127.0.0.1:2181"
    session.timeout = 6000
    connect.timeout = 2000
  }
  consul {
    cluster = "default"
    serverAddr = "127.0.0.1:8500"
  }
  etcd3 {
    cluster = "default"
    serverAddr = "http://localhost:2379"
  }
  sofa {
    serverAddr = "127.0.0.1:9603"
    application = "default"
    region = "DEFAULT_ZONE"
    datacenter = "DefaultDataCenter"
    cluster = "default"
    group = "SEATA_GROUP"
    addressWaitTime = "3000"
  }
  file {
    name = "file.conf"
  }
}
 
config {
  # file、nacos 、apollo、zk、consul、etcd3
  type = "file"
 
  nacos {
    serverAddr = "localhost"
    namespace = ""
  }
  consul {
    serverAddr = "127.0.0.1:8500"
  }
  apollo {
    app.id = "seata-server"
    apollo.meta = "http://192.168.1.204:8801"
  }
  zk {
    serverAddr = "127.0.0.1:2181"
    session.timeout = 6000
    connect.timeout = 2000
  }
  etcd3 {
    serverAddr = "http://localhost:2379"
  }
  file {
    name = "file.conf"
  }
}

6.domain

CommonResult

@Data
@AllArgsConstructor
@NoArgsConstructor
public class CommonResult<T> {
    private Integer code;
    private String message;
    private T data;

    public CommonResult(Integer code, String message) {
        this(code, message, null);
    }
}

Order

7.Dao接口实现

OrderDao

@Mapper
public interface OrderDao {
    /**
     * 1 新建订单
     * @param order
     * @return
     */
    int create(Order order);

    /**
     * 2 修改订单状态,从0改为1
     * @param userId
     * @param status
     * @return
     */
    int update(@Param("userId") Long userId, @Param("status") Integer status);
}

resources文件夹下新建mapper文件夹后添加

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.eiletxie.springcloud.alibaba.dao.OrderDao">

    <resultMap id="BaseResultMap" type="com.eiletxie.springcloud.alibaba.domain.Order">
        <id column="id" property="id" jdbcType="BIGINT"></id>
        <result column="user_id" property="userId" jdbcType="BIGINT"></result>
        <result column="product_id" property="productId" jdbcType="BIGINT"></result>
        <result column="count" property="count" jdbcType="INTEGER"></result>
        <result column="money" property="money" jdbcType="DECIMAL"></result>
        <result column="status" property="status" jdbcType="INTEGER"></result>
    </resultMap>

    <insert id="create" parameterType="com.eiletxie.springcloud.alibaba.domain.Order" useGeneratedKeys="true"
            keyProperty="id">
        insert into t_order(user_id,product_id,count,money,status) values (#{userId},#{productId},#{count},#{money},0);
    </insert>

    <update id="update">
        update t_order set status =1 where user_id =#{userId} and status=#{status};
    </update>
</mapper>

OrderMapper.xml

8.Service接口及实现

OrderService

public interface OrderService {

    /**
     * 创建订单
     * @param order
     */
    void create(Order order);
}

---

@Service
@Slf4j
public class OrderServiceImpl implements OrderService {

    @Resource
    private OrderDao orderDao;
    @Resource
    private AccountService accountService;
    @Resource
    private StorageService storageService;

    /**
     * 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
     * GlobalTransactional seata开启分布式事务,异常时回滚,name保证唯一即可
     * @param order 订单对象
     */
    @Override
    ///@GlobalTransactional(name = "fsp-create-order", rollbackFor = Exception.class)
    public void create(Order order) {
        // 1 新建订单
        log.info("----->开始新建订单");
        orderDao.create(order);

        // 2 扣减库存
        log.info("----->订单微服务开始调用库存,做扣减Count");
        storageService.decrease(order.getProductId(), order.getCount());
        log.info("----->订单微服务开始调用库存,做扣减End");

        // 3 扣减账户
        log.info("----->订单微服务开始调用账户,做扣减Money");
        accountService.decrease(order.getUserId(), order.getMoney());
        log.info("----->订单微服务开始调用账户,做扣减End");

        // 4 修改订单状态,从0到1,1代表已完成
        log.info("----->修改订单状态开始");
        orderDao.update(order.getUserId(), 0);

        log.info("----->下订单结束了,O(∩_∩)O哈哈~");
    }
}

AccountService

@FeignClient(value = "seata-account-service")
public interface AccountService {

    /**
     * 减余额
     * @param userId
     * @param money
     * @return
     */
    @PostMapping(value = "/account/decrease")
    CommonResult decrease(@RequestParam("userId") Long userId, @RequestParam("money") BigDecimal money);
}

StorageService

@FeignClient(value = "seata-storage-service")
public interface StorageService {

    /**
     * 减库存
     * @param productId
     * @param count
     * @return
     */
    @PostMapping(value = "/storage/decrease")
    CommonResult decrease(@RequestParam("productId") Long productId, @RequestParam("count") Integer count);
}

9.Controller

OrderController

@RestController
public class OrderController {
    @Resource
    private OrderService orderService;


    /**
     * 创建订单
     *
     * @param order
     * @return
     */
    @GetMapping("/order/create")
    public CommonResult create(Order order) {
        orderService.create(order);
        return new CommonResult(200, "订单创建成功");
    }
}

10.Config配置

MyBatisConfig

@Configuration
@MapperScan({"com.eiletxie.springcloud.alibaba.dao"})
public class MyBatisConfig {

}

DataSourceProxyConfig

import com.alibaba.druid.pool.DruidDataSource;
import io.seata.rm.datasource.DataSourceProxy;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;

import javax.sql.DataSource;

/**
 * @Author EiletXie
 * @Since 2020/3/18 21:51
 * 使用Seata对数据源进行代理
 */
@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 druidDataSource) {
        return new DataSourceProxy(druidDataSource);
    }

    @Bean
    public SqlSessionFactory sqlSessionFactoryBean(DataSourceProxy dataSourceProxy) throws Exception {
        SqlSessionFactoryBean bean = new SqlSessionFactoryBean();
        bean.setDataSource(dataSourceProxy);
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        bean.setMapperLocations(resolver.getResources(mapperLocations));
        return bean.getObject();
    }
}

11.主启动

@SpringBootApplication(exclude = DataSourceAutoConfiguration.class) //取消数据源的自动创建
@EnableDiscoveryClient
@EnableFeignClients
public class SeataOrderMain2001 {

    public static void main(String[] args) {
        SpringApplication.run(SeataOrderMain2001.class,args);
    }
}

新建库存Storage-Module

1、seata-storage-service2002

基本和2001一样，除了dao层和mapper有点区别

2、POM

3、YML

server:
  port: 2002



spring:
  application:
    name: seata-storage-service
  cloud:
    alibaba:
      seata:
        tx-service-group: fsp_tx_group
    nacos:
      discovery:
        server-addr: localhost:8848
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
      # mysql驱动类
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/seata_storage?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8
    username: root
    password: root


feign:
  hystrix:
    enabled: false
logging:
  level:
    io:
      seata: info

mybatis:
  mapperLocations: classpath*:mapper/*.xml

4、file.conf

5、registry.conf

6、domain

CommonResult

和2001一样

Storage

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Storage {

    private Long id;

    private Integer total;

    private Integer used;

    private Integer  residue;
}

7、Dao接口及实现

StorageDao

@Mapper
public interface StorageDao {

    void decrease(@Param("productId") Long productId,@Param("count") Integer count);
}

resources文件夹下新建mapper文件夹后添加

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.eiletxie.springcloud.alibaba.dao.StorageDao">

    <resultMap id="BaseResultMap" type="com.eiletxie.springcloud.alibaba.domain.Storage">
        <id column="id" property="id" jdbcType="BIGINT"></id>
        <result column="product_id" property="productId" jdbcType="BIGINT"></result>
        <result column="total" property="total" jdbcType="INTEGER"></result>
        <result column="used" property="used" jdbcType="INTEGER"></result>
        <result column="residue" property="residue" jdbcType="INTEGER"></result>
    </resultMap>

    <update id="decrease">
        update t_storage
        set used = used + #{count},residue = residue - #{count}
        where  product_id= #{productId};
    </update>
</mapper>

8、Service接口及实现

StorageService

public interface StorageService {

    void decrease(Long productId, Integer count);

}

StorageServiceImpl

@Service
public class StorageServiceImpl implements StorageService {

    private static final Logger LOGGER = LoggerFactory.getLogger(StorageServiceImpl.class);

    @Resource
    private StorageDao storageDao;

    @Override
    public void decrease(Long productId, Integer count) {
        LOGGER.info("----> storage-service中扣减库存开始");
        storageDao.decrease(productId,count);
        LOGGER.info("----> storage-service中扣减库存结束");
    }
}

9、Controller

StorageController

@RestController
public class StorageController {

    @Resource
    private StorageService storageService;

    @RequestMapping("/storage/decrease")
    public CommonResult decrease(Long productId,Integer count) {
        storageService.decrease(productId, count);
        return new CommonResult(200,"扣减库存成功!");
    }
}

10、Config配置

和2001一样

11、主启动

@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
@EnableFeignClients
@EnableDiscoveryClient
public class SeataStorageMain2002 {

    public static void main(String[] args) {
        SpringApplication.run(SeataStorageMain2002.class,args);
    }
}

新建账户Account-Module

1、seata-account-service2003

6、domain

CommonResult

和2001一样

Account

7、Dao接口及实现

AccountDao

@Mapper
public interface AccountDao {

    /**
     * 扣减账户余额
     * @param userId
     * @param money
     */
    void decrease(@Param("userId") Long userId, @Param("money") BigDecimal money);

}

resources文件夹下新建mapper文件夹后添加

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.eiletxie.springcloud.alibaba.dao.AccountDao">

    <resultMap id="BaseResultMap" type="com.eiletxie.springcloud.alibaba.domain.Account">
        <id column="id" property="id" jdbcType="BIGINT"></id>
        <result column="user_id" property="userId" jdbcType="BIGINT"></result>
        <result column="total" property="total" jdbcType="DECIMAL"></result>
        <result column="used" property="used" jdbcType="DECIMAL"></result>
        <result column="residue" property="residue" jdbcType="DECIMAL"></result>
    </resultMap>

    <update id="decrease">
        update t_account
        set used = used + #{money},residue = residue - #{money}
        where  user_id= #{userId};
    </update>
</mapper>

8、Service接口及实现

AccountService

public interface AccountService {

    void decrease(Long userId, BigDecimal money);
}

AccountServiceImpl

@Service
public class AccountServiceImpl implements AccountService {

    private static final Logger LOGGER = LoggerFactory.getLogger(AccountServiceImpl.class);

    @Resource
    private AccountDao accountDao;

    @Override
    public void decrease(Long userId, BigDecimal money) {
        LOGGER.info("----> account-service中扣减用户余额开始");
        accountDao.decrease(userId,money);
        LOGGER.info("----> account-service中扣减用户余额开始");
    }
}

9、Controller

AccountController

@RestController
public class AccountController {

    @Resource
    AccountService accountService;

    @RequestMapping("/account/decrease")
    public CommonResult decrease(@RequestParam("userId") Long userId,@RequestParam("money") BigDecimal money) {
        accountService.decrease(userId,money);
        return new CommonResult(200,"扣减账户余额成功！");
    }
}

11、主启动

@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
@EnableFeignClients
@EnableDiscoveryClient
public class SeataAccountMain2003 {

    public static void main(String[] args) {
        SpringApplication.run(SeataAccountMain2003.class,args);
    }
}

YML

server:
  port: 2003



spring:
  application:
    name: seata-account-service
  cloud:
    alibaba:
      seata:
        tx-service-group: fsp_tx_group
    nacos:
      discovery:
        server-addr: localhost:8848
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    # mysql驱动类
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/seata_account?useUnicode=true&characterEncoding=UTF-8&useSSL=false&serverTimezone=GMT%2B8
    username: root
    password: root


feign:
  hystrix:
    enabled: false
logging:
  level:
    io:
      seata: info

mybatis:
  mapperLocations: classpath*:mapper/*.xml

Test

数据库初始情况

下订单->减库存->扣余额->改订单状态

正常下单

http://localhost:2001/order/create?userId=1&productId=1&count=10&money=100

数据库情况

超时异常，没加@GlobalTransational

• AccountServiceImpl添加超时
• 数据库情况
• 故障情况
  • 当库存和账户金额扣减后，订单状态并没有设置为依据完成，没有从零改为1
  • 而且由于feign的重试机制，账户余额还有可能被多次扣减

超时异常，添加@GlobalTransational

结果

各数据库无记录新增

OrderServiceImpl

@Override
@GlobalTransactional(name = "fsp-create-order",rollbackFor = Exception.class)
///@GlobalTransactional(name = "fsp-create-order", rollbackFor = Exception.class)
public void create(Order order) {
    // 1 新建订单
    log.info("----->开始新建订单");
    orderDao.create(order);

    // 2 扣减库存
    log.info("----->订单微服务开始调用库存,做扣减Count");
    storageService.decrease(order.getProductId(), order.getCount());
    log.info("----->订单微服务开始调用库存,做扣减End");

    // 3 扣减账户
    log.info("----->订单微服务开始调用账户,做扣减Money");
    accountService.decrease(order.getUserId(), order.getMoney());
    log.info("----->订单微服务开始调用账户,做扣减End");

    // 4 修改订单状态,从0到1,1代表已完成
    log.info("----->修改订单状态开始");
    orderDao.update(order.getUserId(), 0);

    log.info("----->下订单结束了,O(∩_∩)O哈哈~");
}

一部分补充

Seata

• 2019年1月份蚂蚁金服和阿里巴巴共同开源的分布式事务解决方案
• Simple Extensible Autonomous Transaction Architecture ,简单可扩展自治事务框架
• 2020起始，参加工作后使用1.0以后的版本
  

再看TC/TM/RM三大组件

分布式事务的执行流程

1. TM开启分布式事务（TM向TC注册全局事务记录）
2. 按业务场景，编排数据库、服务等事务内资源（RM向TC汇报资源准备状态）
3. TM结束分布式事务，事务一阶段结束（TM通知TC提交/回滚分布式事务)
4. TC汇总事务信息，决定分布式事务是提交还是回滚
5. TC通知所有RM提交/回滚 资源，事务二阶段结束

AT模式如何做到对业务的无侵入

是什么

一阶段加载

二阶段提交

二阶段回滚

debug

AccountServiceImpl

undo.log

before image

补充