【SpringCloudAlibaba】Seata解决分布式事务小能手【详解】

前言

本篇博客主要是向大家分享seata是什么，怎么安装，通过demo展示，向大家介绍他是如何解决分布式事务问题，希望能帮助小伙伴们。

---

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。
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
  1.Transaction ID XID :全局唯一的事务ID
  2.3个组件概念：
  Transaction Coordinator(TC)事务协调器：
  维护全局事务和分支事务的状态，驱动全局事务提交或回滚
  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。
  Resource Manager(RM):资源管理器
  管理分支事务处理的资源，与CT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。
  
  通过上面图片，我们大概知道：
  1.TM向TC申请开启了一个全局事务，全局事务创建成功并生成一个全局唯一的XID；
  2.XID在微服务调用链路的上下文中传播；
  3.RM向TC注册分支事务，将其纳入XID对应全局事务的管辖；
  4.TM向TC 发起针对XID的全局提交或回滚决议；
  5.TC调度XID下管辖的全部分支事务完成提交或回滚请求
• 处理过程
  
  下载安装
  http://seata.io/en-us/blog/download.html
  
  注意事项
  1.seata-server-x.x.x.zip解压到指定目录并修改conf目录下的file.com配置文件
  2.在mysql数据库中创建seata库
  3.在seata库里创建我们需要的表
  
• 修改我们的配置文件 file.conf
  1.先备份原始file.conf文件
  
  2.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
  3.file.conf:
  【service模块】
  
  修改后：
  
  【store模块】
  
  修改后

url: jdbc:mysql://localhost:3306/mydb01?serverTimezone=UTC

创建表：

• 修改我们registry.conf配置文件

C:\seata-server-0.9.0\seata\conf

修改后：

创建微服务

创建三个服务，一个订单服务，一个库存服务，一个账户服务。
当账户下单时，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。

订单/库存/账户业务数据库准备

• 创建数据库
  seata_order: 存储订单的数据库

  CREATE DATABASE seata_order;

seata_storage:存储库存的数据库

  CREATE DATABASE seata_storage;

seata_account: 存储账户信息的数据库

  CREATE DATABASE seata_account;

• 按照上述3库分别建立对应业务表
  1.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=7 DEFAULT CHARSET=utf8;

2.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 =2 DEFAULT CHARSET=utf8;


INSERT INTO seata_storage.t_storage(`id`,`produce_id`,`total`,`used`,`residue`)VALUES(`1`,`1`,`100`,`0`,`100`);

3.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=2 DEFAULT CHARSET=utf8;


INSERT INTO seata_account.t_account(`id`,`user_id`,`total`,`used`,`residue`)VALUES('1','1','1000','0','1000');

• 按照上述3库分别建对应的回滚日志表
  订单-库存-账号 3个库下都需要建各自的回滚日志表

C:\seata-server-0.9.0\seata\conf

-- 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;

执行完以后：

订单/库存/账户业务微服务准备

【下订单】->【减库存】->【扣余额】->【改（订单）状态】

• 新建订单Order-Module
  1.创建Module
  
  
  
  2.修改POM

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>com.zcw.springcloud2020508</artifactId>
        <groupId>com.zcw</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>seta-order0service2001</artifactId>
    <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.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.1.1</version>
        </dependency>
    </dependencies>

</project>

3.创建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中对应
        tx-service-group: zcw_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: root

feign:
  hystrix:
    enabled: true

logging:
  level:
    io:
      seata: info

mybatis:
  mapperLocations: classpath:mapper/*.xml
  

4.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
  vgroup_mapping.zcw_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 = "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://localhost:3306/seata?serverTimezone=UTC"
    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

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"
  }
}

6.entity

package com.zcw.springcloud.alibaba.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @ClassName : CommonResult
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 13:51
 */
@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);
    }
}

package com.zcw.springcloud.alibaba.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.math.BigDecimal;

/**
 * @ClassName : Order
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 13:55
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Order {
    private Long id;
    private Long userId;
    private Long productId;
    private Integer count;
    private BigDecimal money;
    //订单状态：0 ，创建中1，已完结
    private Integer status;
}

7.Dao接口及实现

package com.zcw.springcloud.alibaba.dao;

import com.zcw.springcloud.alibaba.entity.Order;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

/**
 * @ClassName : OrderDao
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 14:22
 */
@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);
}

<?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.zcw.springcloud.alibaba.dao.OrderDao">
    <resultMap id="BaseResultMap" type="com.zcw.springcloud.alibaba.entity.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>

8.Service接口及实现

package com.zcw.springcloud.alibaba.service;

import com.zcw.springcloud.alibaba.entity.Order;

/**
 * @ClassName : OrderService
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 15:19
 */
public interface OrderService {
    void create(Order order);
}

package com.zcw.springcloud.alibaba.service;

import com.zcw.springcloud.alibaba.entity.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;

/**
 * @ClassName : AccountService
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 15:19
 */
 @Component
@FeignClient(value = "seata-account-servcie")
public interface AccountService {
    @PostMapping(value="/account/decrease")
    CommonResult decrease(@RequestParam("userId") Long userId,@RequestParam("money") BigDecimal money);
}

package com.zcw.springcloud.alibaba.service;

import com.zcw.springcloud.alibaba.entity.CommonResult;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;

/**
 * @ClassName : StorageService
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 15:20
 */
 @Component
@FeignClient(value = "seata-storage-service")
public interface StorageService {
    //数量上进行扣减
    @PostMapping(value = "/storage/decrease")
    CommonResult decrease(@RequestParam("produceId") Long productId,
                          @RequestParam("count") Integer count);
}

package com.zcw.springcloud.alibaba.service.impl;

import com.zcw.springcloud.alibaba.dao.OrderDao;
import com.zcw.springcloud.alibaba.entity.Order;
import com.zcw.springcloud.alibaba.service.AccountService;
import com.zcw.springcloud.alibaba.service.OrderService;
import com.zcw.springcloud.alibaba.service.StorageService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

/**
 * @ClassName : OrderServiceImpl
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 15:21
 */
@Service
@Slf4j
public class OrderServiceImpl implements OrderService {
    @Resource
    private OrderDao orderDao;
    @Resource
    private StorageService storageService;
    @Resource
    private AccountService accountService;

    @Override
    public void create(Order order) {
        log.info("------>开始新建订单");
        //1新建订单
        orderDao.create(order);
        log.info("----->订单微服务开始调用库存，做扣减Count");
        //2扣减库存
        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());
        //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("---->下订单结束了，O(∩_∩)O哈哈~");
    }
}

9.controller

package com.zcw.springcloud.alibaba.controller;

import com.zcw.springcloud.alibaba.entity.CommonResult;
import com.zcw.springcloud.alibaba.entity.Order;
import com.zcw.springcloud.alibaba.service.OrderService;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

/**
 * @ClassName : OrderController
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 15:51
 */
@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");
    }
}

11.Config配置

package com.zcw.springcloud.alibaba.config;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Configuration;

/**
 * @ClassName : MyBatisConfig
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 15:56
 */
@Configuration
@MapperScan({"com.zcw.springcloud.alibaba.dao"})
public class MyBatisConfig {
}

package com.zcw.springcloud.alibaba.config;



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;

/**
 * @ClassName : DataSourceProxyConfig
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 15:56
 */
@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.setMapperLocations(new PathMatchingResourcePatternResolver().getResources(mapperLocations));
        sqlSessionFactoryBean.setTransactionFactory(new SpringManagedTransactionFactory());
        return sqlSessionFactoryBean.getObject();
    }
}

12.创建启动类

package com.zcw.springcloud.alibaba;

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;

/**
 * @ClassName : SeataOrderApplication
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 14:28
 */
@EnableDiscoveryClient
@EnableFeignClients
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)//取消数据源的自动创建
public class SeataOrderApplication {
    public static void main(String[] args) {
        SpringApplication.run(SeataOrderApplication.class,args);
    }
}

• 新建库存Storage-Module
  
  
  
• pom文件

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>com.zcw.springcloud2020508</artifactId>
        <groupId>com.zcw</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>seata-storage-service2002</artifactId>
    <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.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.1.1</version>
        </dependency>
    </dependencies>

</project>

• yml文件

server:
  port: 2002

spring:
  application:
    name: seata-storage-service
  cloud:
    alibaba:
      seata:
        tx-service-group: zcw_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: root
logging:
  level:
    io:
      seata: info

mybatis:
  mapperLocations: classpath:mapper/*.xml

• 创建实体类：

package com.zcw.springcloud.alibaba.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

/**
 * @ClassName : Storage
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 17:03
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Storage {

    private Long id;
    private Long productId;
    private Integer total;
    private Integer used;

    private Integer residue;
}

• dao

package com.zcw.springcloud.alibaba.dao;

import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

/**
 * @ClassName : StorageDao
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 17:09
 */
@Mapper
public interface StorageDao {
    /**
     * 扣减库存
     */
    void  decrease (@Param("productId") Long productId, @Param("count") Integer count);
}

<?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.zcw.springcloud.alibaba.dao.StorageDao">
    <resultMap id="BaseResultMap" type="com.zcw.springcloud.alibaba.entity.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>


    <insert id="decrease">
      UPDATE
      t_storage
      SET used = used +#{count},residue = residue- #{count}
      WHERE
      product_id = #{productId}
    </insert>
</mapper>

• service

package com.zcw.springcloud.alibaba.service;

/**
 * @ClassName : StorageService
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 17:25
 */
public interface StorageService {
    /**
     * 
扣减库存
     * @param productId
     * @param count
     */
    void decrease(Long productId,Integer count);
}

package com.zcw.springcloud.alibaba.service.impl;

import com.zcw.springcloud.alibaba.dao.StorageDao;
import com.zcw.springcloud.alibaba.service.StorageService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

/**
 * @ClassName : StorageServiceImpl
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 17:27
 */
@Service
@Slf4j
public class StorageServiceImpl  implements StorageService {
    @Resource
    private StorageDao storageDao;

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

• controller

package com.zcw.springcloud.alibaba.controller;

import com.zcw.springcloud.alibaba.entity.CommonResult;
import com.zcw.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;

/**
 * @ClassName : StorageController
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 17:31
 */
@RestController
public class StorageController {
    @Autowired
    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");
    }
}

• 创建配置类
  
• 创建启动类：

package com.zcw.springcloud.alibaba;

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;

/**
 * @ClassName : SeataStorageServiceApplication
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 17:34
 */
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
@EnableDiscoveryClient
@EnableFeignClients
public class SeataStorageServiceApplication {
    public static void main(String[] args) {
        SpringApplication.run(SeataStorageServiceApplication.class,args);
    }
}

• 新建账号Account-Module
  更上面结构一样，只是在这里只不同的代码提出来

server:
  port: 2003

spring:
  application:
    name: seata-account-service
  cloud:
    alibaba:
      seata:
        tx-service-group: zcw_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: root
feign:
  hystrix:
    enabled: true
logging:
  level:
    io:
      seata: info
mybatis:
  mapperLocations: classpath:mapper/*.xml

• 创建实体类

package alibaba.entity;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.math.BigDecimal;

/**
 * @ClassName : Account
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 17:51
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Account {
    private Long id;
    private Long userId;
    private BigDecimal total;
    private BigDecimal used;
    private BigDecimal residue;
}

• 创建Dao层

package alibaba.dao;

import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

import java.math.BigDecimal;

/**
 * @ClassName : AccountDao
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 17:54
 */
@Mapper
public interface AccountDao {
    /**
     * 扣减账户余额
     */
    void decrease(@Param("userId")Long userId,@Param("money") BigDecimal money);
}

<?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.zcw.springcloud.alibaba.dao.AccountDao">
    <resultMap id="BaseResultMap" type="com.zcw.springcloud.alibaba.entity.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},userd= used+#{money}
         WHERE
         user_id =#{userId};
     </update>

</mapper>

• service

package com.zcw.springcloud.alibaba.service;

import org.springframework.web.bind.annotation.RequestParam;

import java.math.BigDecimal;

/**
 * @ClassName : AccountService
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 18:28
 */
public interface AccountService {
    void decrease(@RequestParam("uderId") Long userId, @RequestParam("money")BigDecimal money);
}

package com.zcw.springcloud.alibaba.service.impl;

import com.zcw.springcloud.alibaba.dao.AccountDao;
import com.zcw.springcloud.alibaba.service.AccountService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.math.BigDecimal;

/**
 * @ClassName : AccountServiceImpl
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 18:30
 */
@Service
@Slf4j
public class AccountServiceImpl implements AccountService {
    @Resource
    AccountDao accountDao;
    @Override
    public void decrease(Long userId, BigDecimal money) {
        log.info("---->account-service中加减账户余额开始");
        //模拟超时异常，全局事务回滚
        accountDao.decrease(userId,money);
        log.info("---->account-service中扣减账户余额结束");
    }
}

• controller层

package com.zcw.springcloud.alibaba.controller;

import com.zcw.springcloud.alibaba.entity.CommonResult;
import com.zcw.springcloud.alibaba.service.AccountService;
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;

/**
 * @ClassName : AccountController
 * @Description :
 * @Author : Zhaocunwei
 * @Date: 2020-05-29 18:33
 */
@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");
    }
}

测试：

• 正常下单：
  2001订单的入口：
  
  
• 刚才报错，这样也一直能操作数据库，
  
  还剩下900元：
  
  

【超时异常，没加@GlobalTransactional】

• 运行测试
  
• 查看数据库

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，添加@GlobalTransactional】

• AccountServiceImpl添加超时
• OrderServiceImpl 添加@GlobalTransactional
  
  
  

Seata原理讲解:简单可扩展自治事务框架

• TC/TM/RM三大组件

【分布式事务执行流程】
第一步：TM开启分布式事务（TM向TC注册全局事务记录）；
第二步：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）;
第三步：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）;
第四步：TC汇总事务信息，决定分布式事务是提交还是回滚；
第五步：TC通知所有RM提交/回滚资源，事务二阶段结束。

• AT模式（默认）如何做到对业务的无侵入
  一阶段加载：
  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：
  提交异步化，非常快速地完成。
  
  二阶段回滚：
  回滚通过一阶段的回滚日志进行反向补偿。
  
  
  来源:网上