Spring Cloud Alibaba : Seata
Cloud Alibaba : Seata
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。
官方文档 ： https://seata.io/zh-cn/
一个典型的分布式事务过程，分布式事务处理过程的一 ID + 三 组件模型：
-
Transaction ID XID 全局唯一的事务ID
-
三组件概念
- TC (Transaction Coordinator) - 事务协调者：维护全局和分支事务的状态，驱动全局事务提交或回滚
- TM (Transaction Manager) - 事务管理器：定义全局事务的范围：开始全局事务、提交或回滚全局事务
- RM (Resource Manager) - 资源管理器：管理分支事务处理的资源，与TC交谈以注册分支事务和报告分支事务的状态，并驱动分支事务提交或回滚
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
安装与使用
下载 ：
https://github.com/seata/seata/releases
本地@Transactional
全局@GlobalTransactional
只需要使用一个
@GlobalTransactional注解在业务方法上
SEATA 的分布式交易解决方案
Seata-Server 安装
下载版本 - 0.9.0
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
- 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 + 数据库连接信息
service模块
service {
## fsp_tx_group是自定义的
vgroup_mapping.my.test.tx_group="fsp_tx_group"
default.grouplist = "127.0.0.1:8091"
enableDegrade = false
disable = false
max.commitretry.timeout= "-1"
max.ollbackretry.timeout= "-1"
}
store模块
## transaction log store
store {
## store mode: file, db
## 改成db
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.
## 配置数据源
db-type = "mysql"
driver-class-name = "com.mysql.jdbc.Driver"
url = "jdbc:mysql://127.0.0.1:3306/seata"
user = "root"
password = "你自己密码"
min-conn= 1
max-conn = 3
global.table = "global_table"
branch.table = "branch_table"
lock-table = "lock_table"
query-limit = 100
}
}
mysql5.7数据库新建库seata，在 seata 库中建表
建表
db_store.sql在\seata-server-0.9.0\seata\conf目录里面
-- 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`)
);
修改
seata-server-0.9.0\seata\conf目录下的registry.conf配置文件
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
# 改用为nacos
type = "nacos"
nacos {
## 加端口号
serverAddr = "localhost:8848"
namespace = ""
cluster = "default"
}
...
}
目的是：指明注册中心为 nacos，及修改 nacos 连接信息
-
先启动 Nacos 端口号 8848
nacos\bin\startup.cmd -
再启动
seata-server - seata-server-0.9.0\seata\bin\seata-server.bat
业务示例
业务数据库搭建
以下演示都需要先启动
Nacos后，启动Seata
分布式事务业务说明
- 这里会创建三个服务，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
下订单—>扣库存—>减账户 (余额)
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
CREATE DATABASE seata_order;
CREATE DATABASE seata_storage;
CREATE DATABASE seata_account;
seata_order 库下建 t_order 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;
seata_storage 库下建 t_storage 表
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 seata_storage.t_storage(`id`, `product_id`, `total`, `used`, `residue`)
VALUES ('1', '1', '100', '0','100');
seata_account 库下建 t_account 表
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=1 DEFAULT CHARSET=utf8;
INSERT INTO seata_account.t_account(`id`, `user_id`, `total`, `used`, `residue`)
VALUES ('1', '1', '1000', '0', '1000');
建立回滚日志表
上述 3 库分别建对应的回滚日志表
- 订单-库存-账户3个库下都需要建各自的回滚日志表
\seata-server-0.9.0\seata\conf目录下的db_ undo_ log.sql
-- the table to store seata xid data
-- 0.7.0+ add context
-- you must to init this sql for you business databese. the seata server not need it.
-- 此脚本必须初始化在你当前的业务数据库中，用于AT 模式XID记录。与server端无关（注：业务数据库）
-- 注意此处0.3.0+ 增加唯一索引 ux_undo_log
drop table `undo_log`;
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;
业务模块搭建
Order- Module 配置搭建
下订单 -> 减库存 -> 扣余额 -> 改（订单）状态
新建 Module ：seata-order-service2001
POM 文件
<artifactId>seata-order-service2001artifactId>
<dependencies>
<dependency>
<groupId>com.alibaba.cloudgroupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discoveryartifactId>
dependency>
<dependency>
<groupId>com.alibaba.cloudgroupId>
<artifactId>spring-cloud-starter-alibaba-seataartifactId>
<exclusions>
<exclusion>
<artifactId>seata-allartifactId>
<groupId>io.seatagroupId>
exclusion>
exclusions>
dependency>
<dependency>
<groupId>io.seatagroupId>
<artifactId>seata-allartifactId>
<version>0.9.0version>
dependency>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-openfeignartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-actuatorartifactId>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>5.1.37version>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>druid-spring-boot-starterartifactId>
<version>1.1.10version>
dependency>
<dependency>
<groupId>org.mybatis.spring.bootgroupId>
<artifactId>mybatis-spring-boot-starterartifactId>
<version>2.0.0version>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<optional>trueoptional>
dependency>
dependencies>
YML 配置文件
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: localhost:8848
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/seata_order
username: root
password: 123456
feign:
hystrix:
enabled: false
logging:
level:
io:
seata: info
mybatis:
mapperLocations: classpath:mapper/*.xml
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_mapping.fsp_tx_group = "default" #修改自定义事务组名称
default.grouplist = "127.0.0.1:8091"
enableDegrade = false
disable = false
max.commit.retry.timeout = "-1"
max.rollback.retry.timeout = "-1"
disableGlobalTransaction = false
}
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 = "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 = "123456"
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
}
}
registry.conf
registry {
# file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
type = "nacos"
nacos {
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"
}
}
domain 实体
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@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);
}
}
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.math.BigDecimal;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Order{
private Long id;
private Long userId;
private Long productId;
private Integer count;
private BigDecimal money;
private Integer status; //订单状态：0：创建中；1：已完结
}
Dao 接口
import com.atguigu.springcloud.alibaba.domain.Order;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
@Mapper
public interface OrderDao{
//1 新建订单
void create(Order order);
//2 修改订单状态，从零改为1
void update(@Param("userId") Long userId,@Param("status") Integer status);
}
<mapper namespace="com.atguigu.springcloud.alibaba.dao.OrderDao">
<resultMap id="BaseResultMap" type="com.atguigu.springcloud.alibaba.domain.Order">
<id column="id" property="id" jdbcType="BIGINT"/>
<result column="user_id" property="userId" jdbcType="BIGINT"/>
<result column="product_id" property="productId" jdbcType="BIGINT"/>
<result column="count" property="count" jdbcType="INTEGER"/>
<result column="money" property="money" jdbcType="DECIMAL"/>
<result column="status" property="status" jdbcType="INTEGER"/>
resultMap>
<insert id="create">
insert into t_order (id,user_id,product_id,count,money,status)
values (null,#{userId},#{productId},#{count},#{money},0);
insert>
<update id="update">
update t_order set status = 1
where user_id=#{userId} and status = #{status};
update>
mapper>
Service 接口
- OrderService
- OrderServiceImpl
- StorageService
- AccountService
import com.atguigu.springcloud.alibaba.domain.Order;
public interface OrderService{
void create(Order order);
}
import com.atguigu.springcloud.alibaba.domain.CommonResult;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import java.math.BigDecimal;
@FeignClient(value = "seata-storage-service")
public interface StorageService{
@PostMapping(value = "/storage/decrease")
CommonResult decrease(@RequestParam("productId") Long productId, @RequestParam("count") Integer count);
}
import com.atguigu.springcloud.alibaba.domain.CommonResult;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import java.math.BigDecimal;
@FeignClient(value = "seata-account-service")
public interface AccountService{
@PostMapping(value = "/account/decrease")
CommonResult decrease(@RequestParam("userId") Long userId, @RequestParam("money") BigDecimal money);
}
import com.atguigu.springcloud.alibaba.dao.OrderDao;
import com.atguigu.springcloud.alibaba.domain.Order;
import com.atguigu.springcloud.alibaba.service.AccountService;
import com.atguigu.springcloud.alibaba.service.OrderService;
import com.atguigu.springcloud.alibaba.service.StorageService;
import io.seata.spring.annotation.GlobalTransactional;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
@Service
@Slf4j
public class OrderServiceImpl implements OrderService{
@Resource
private OrderDao orderDao;
@Resource
private StorageService storageService;
@Resource
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->扣库存->减余额->改状态
*/
@Override
//@GlobalTransactional(name = "fsp-create-order",rollbackFor = Exception.class)
public void create(Order order)
{
log.info("----->开始新建订单");
//1 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，从零到1,1代表已经完成
log.info("----->修改订单状态开始");
orderDao.update(order.getUserId(),0);
log.info("----->修改订单状态结束");
log.info("----->下订单结束了，O(∩_∩)O哈哈~");
}
}
Controller
import com.atguigu.springcloud.alibaba.domain.CommonResult;
import com.atguigu.springcloud.alibaba.domain.Order;
import com.atguigu.springcloud.alibaba.service.OrderService;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
@RestController
public class OrderController{
@Resource
private OrderService orderService;
@GetMapping("/order/create")
public CommonResult create(Order order){
orderService.create(order);
return new CommonResult(200,"订单创建成功");
}
}
Config 配置
- MyBatisConfig
- DataSourceProxyConfig
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Configuration;
@Configuration
@MapperScan({"com.atguigu.springcloud.alibaba.dao"})
public class MyBatisConfig {}
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.mybatis.spring.transaction.SpringManagedTransactionFactory;
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 javax.sql.DataSource;
/**
* 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 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();
}
}
主启动
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
@EnableDiscoveryClient
@EnableFeignClients
// 取消数据源的自动创建，而是使用自己定义的
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
public class SeataOrderMainApp2001{
public static void main(String[] args){
SpringApplication.run(SeataOrderMainApp2001.class, args);
}
}
Storage-Module 配置搭建
新建 Module ：
seata-storage-service2002
POM（与seata-order-service2001模块大致相同）
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:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/seata_storage
username: root
password: 123456
logging:
level:
io:
seata: info
mybatis:
mapperLocations: classpath:mapper/*.xml
file.conf（与seata-order-service2001模块大致相同）
registry.conf（与seata-order-service2001模块大致相同）
domain 实体
import lombok.Data;
@Data
public class Storage {
private Long id;
/**
* 产品id
*/
private Long productId;
/**
* 总库存
*/
private Integer total;
/**
* 已用库存
*/
private Integer used;
/**
* 剩余库存
*/
private Integer residue;
}
CommonResult（与seata-order-service2001模块大致相同）
Dao 接口
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
@Mapper
public interface StorageDao {
//扣减库存
void decrease(@Param("productId") Long productId, @Param("count") Integer count);
}
<mapper namespace="com.atguigu.springcloud.alibaba.dao.StorageDao">
<resultMap id="BaseResultMap" type="com.atguigu.springcloud.alibaba.domain.Storage">
<id column="id" property="id" jdbcType="BIGINT"/>
<result column="product_id" property="productId" jdbcType="BIGINT"/>
<result column="total" property="total" jdbcType="INTEGER"/>
<result column="used" property="used" jdbcType="INTEGER"/>
<result column="residue" property="residue" jdbcType="INTEGER"/>
resultMap>
<update id="decrease">
UPDATE
t_storage
SET
used = used + #{count},residue = residue - #{count}
WHERE
product_id = #{productId}
update>
mapper>
Service 接口
public interface StorageService {
/**
* 扣减库存
*/
void decrease(Long productId, Integer count);
}
import com.atguigu.springcloud.alibaba.dao.StorageDao;
import com.atguigu.springcloud.alibaba.service.StorageService ;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
@Service
public class StorageServiceImpl implements StorageService {
private static final Logger LOGGER = LoggerFactory.getLogger(StorageServiceImpl.class);
@Resource
private StorageDao storageDao;
/**
* 扣减库存
*/
@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");
}
}
Controller
import com.atguigu.springcloud.alibaba.domain.CommonResult ;
import com.atguigu.springcloud.alibaba.service.StorageService ;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class StorageController {
@Autowired
private StorageService storageService;
/**
* 扣减库存
*/
@RequestMapping("/storage/decrease")
public CommonResult decrease(Long productId, Integer count) {
storageService.decrease(productId, count);
return new CommonResult(200,"扣减库存成功！");
}
}
Config 配置（与seata-order-service2001模块大致相同）
主启动（与seata-order-service2001模块大致相同）
Account-Module 配置搭建
新建 Module ：
seata-account-service2003
POM 与seata-order-service2001模块大致相同
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:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/seata_account
username: root
password: 123456
feign:
hystrix:
enabled: false
logging:
level:
io:
seata: info
mybatis:
mapperLocations: classpath:mapper/*.xml
file.conf（与seata-order-service2001模块大致相同）
registry.conf（与seata-order-service2001模块大致相同）
domain 实体
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.math.BigDecimal;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Account {
private Long id;
/**
* 用户id
*/
private Long userId;
/**
* 总额度
*/
private BigDecimal total;
/**
* 已用额度
*/
private BigDecimal used;
/**
* 剩余额度
*/
private BigDecimal residue;
}
CommonResult（与seata-order-service2001模块大致相同）
Dao 接口
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Repository;
import java.math.BigDecimal;
@Mapper
public interface AccountDao {
/**
* 扣减账户余额
*/
void decrease(@Param("userId") Long userId, @Param("money") BigDecimal money);
}
<mapper namespace="com.atguigu.springcloud.alibaba.dao.AccountDao">
<resultMap id="BaseResultMap" type="com.atguigu.springcloud.alibaba.domain.Account">
<id column="id" property="id" jdbcType="BIGINT"/>
<result column="user_id" property="userId" jdbcType="BIGINT"/>
<result column="total" property="total" jdbcType="DECIMAL"/>
<result column="used" property="used" jdbcType="DECIMAL"/>
<result column="residue" property="residue" jdbcType="DECIMAL"/>
resultMap>
<update id="decrease">
UPDATE t_account
SET
residue = residue - #{money},used = used + #{money}
WHERE
user_id = #{userId};
update>
mapper>
Service 接口
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import java.math.BigDecimal;
public interface AccountService {
/**
* 扣减账户余额
* @param userId 用户id
* @param money 金额
*/
void decrease(@RequestParam("userId") Long userId, @RequestParam("money") BigDecimal money);
}
import com.atguigu.springcloud.alibaba.dao.AccountDao;
import com.atguigu.springcloud.alibaba.service.AccountService ;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.math.BigDecimal;
import java.util.concurrent.TimeUnit;
/**
*/
@Service
public class AccountServiceImpl implements AccountService {
private static final Logger LOGGER = LoggerFactory.getLogger(AccountServiceImpl.class);
@Resource
AccountDao accountDao;
/**
* 扣减账户余额
*/
@Override
public void decrease(Long userId, BigDecimal money) {
LOGGER.info("------->account-service中扣减账户余额开始");
accountDao.decrease(userId,money);
LOGGER.info("------->account-service中扣减账户余额结束");
}
}
Controller
import com.atguigu.springcloud.alibaba.domain.CommonResult ;
import com.atguigu.springcloud.alibaba.service.AccountService ;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
import java.math.BigDecimal;
@RestController
public class AccountController {
@Resource
AccountService accountService;
/**
* 扣减账户余额
*/
@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！");
}
}
Config配置（与seata-order-service2001模块大致相同）
主启动（与seata-order-service2001模块大致相同）
@GlobalTransactional验证
下订单 -> 减库存 -> 扣余额 -> 改（订单）状态
数据库初始情况：
正常下单 - http://localhost:2001/order/create?userId=1&productId=1&count=10&money=100
数据库正常下单后状况：
超时异常，没加 @GlobalTransactional
模拟
AccountServiceImpl添加超时
@Service
public class AccountServiceImpl implements AccountService {
private static final Logger LOGGER = LoggerFactory.getLogger(AccountServiceImpl.class);
@Resource
AccountDao accountDao;
/**
* 扣减账户余额
*/
@Override
public void decrease(Long userId, BigDecimal money) {
LOGGER.info("------->account-service中扣减账户余额开始");
//模拟超时异常，全局事务回滚
//暂停几秒钟线程
try { TimeUnit.SECONDS.sleep(20); } catch (InterruptedException e) { e.printStackTrace(); }
accountDao.decrease(userId,money);
LOGGER.info("------->account-service中扣减账户余额结束");
}
}
OpenFeign的调用默认时间是1s以内，所以最后会抛异常。
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已经完成，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，加了 @GlobalTransactional
用
@GlobalTransactional标注OrderServiceImpl的create()方法
@Service
@Slf4j
public class OrderServiceImpl implements OrderService {
...
/**
* 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->扣库存->减余额->改状态
*/
@Override
//rollbackFor = Exception.class表示对任意异常都进行回滚
@GlobalTransactional(name = "fsp-create-order",rollbackFor = Exception.class)
public void create(Order order){
...
}
}
模拟AccountServiceImpl添加超时，下单后数据库数据并没有任何改变，记录都添加不进来，达到出异常，数据库回滚的效果。
原理简介
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，用1.0以后的版本 : Alina Gingertail
分布式事务的执行流程
- TM开启分布式事务(TM向TC注册全局事务记录)
- 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)
- 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)
- TC汇总事务信息，决定分布式事务是提交还是回滚
- TC通知所有RM提交/回滚资源，事务二阶段结束
AT 模式
前提
- 基于支持本地 ACID 事务的关系型数据库
- Java 应用，通过 JDBC 访问数据库
整体机制
两阶段提交协议的演变：
- 一阶段：业务数据和回滚日志记录在同一个本地事务中提交，释放本地锁和连接资源
- 二阶段：
- 提交异步化，非常快速地完成
- 回滚通过一阶段的回滚日志进行反向补偿
- 一阶段加载
在一阶段，Seata会拦截“业务SQL”
- 解析SQL语义，找到“业务SQL" 要更新的业务数据，在业务数据被更新前，将其保存成"before image”
- 执行“业务SQL" 更新业务数据，在业务数据更新之后
- 其保存成"after image”，最后生成行锁
以上操作全部在一个数据库事务内完成, 这样保证了一阶段操作的原子性
- 二阶段提交
二阶段如果顺利提交的话，因为"业务SQL"在一阶段已经提交至数据库，所以Seata框架只需将一阶段保存的快照数据和行锁删掉，完成数据清理即可
- 二阶段回滚
二阶段如果是回滚的话，Seata 就需要回滚一阶段已经执行的 “业务SQL"，还原业务数据
回滚方式便是用"before image"还原业务数据；但在还原前要首先要校验脏写，对比“数据库当前业务数据”和"after image"
如果两份数据完全一致就说明没有脏写， 可以还原业务数据，如果不一致就说明有脏写, 出现脏写就需要转人工处理
