SpringCloud-2.0-周阳（24. 分布式事务 - Seata）

Posted 2022-06-27 ABin-阿斌

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声明：原文作者：csdn：yuan_404

文章目录

1 . 分布式事务的问题
2 . Seata 简介
3 . Seata-Server 安装
4 . 数据库环境搭建
5 . 代码环境搭建
6 . 整合 Seata 测试

1 . 分布式事务的问题

在分布式之前

是一台电脑上包含所有的东西 —— 所有的数据、程序所有的内容 ……

慢慢向分布式演变

从 1 对 1 （一个程序对应一个数据库）
到 1 对 N （分库，一个程序对应多个数据库）
再 N 对 N （分布式微服务，多个微服务对应多个数据库）

分布式之后

举例：

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。

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

2 . Seata 简介

官网地址：http://seata.io/zh-cn/
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 ID + 三个组件

Transaction ID XID ：全局唯一的事务ID
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™ ：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，并接收事务协调器的指令，驱动分支（本地）事务的提交和回滚；

分布式事务处理过程

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。

3 . Seata-Server 安装

下载地址：https://github.com/seata/seata/releases
将 seata-server 解压到指定目录
修改 conf 目录下的 file.conf 文件

先对配置文件进行备份
在 mysql 中新建一个数据库：seata
初始化数据库

运行 conf 目录下的 db_store.sql 文件

如果没有，请看，SQL 脚本文件地址（选择自己的数据库）：https://github.com/seata/seata/tree/develop/script/server/db
复制下来去 MySQL 执行
修改 conf 目录下的 registry.conf 文件
启动 Nacos
启动 seata-server

双击 seata\\bin\\seata-server.bat

4 . 数据库环境搭建

下面就按照该框架图进行设计

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。

启动 Nacos 、Seata
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;
```

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;
 
SELECT * FROM t_order;

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`,`product_id`,`total`,`used`,`residue`)
VALUES('1','1','100','0','100');
 
SELECT * FROM t_storage;

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')

SELECT * FROM t_account;

建立回滚日志表

找到 Seat 中回滚日志建表 SQL 脚本：\\seata\\conf\\db_undo_log.sql

三个数据库都需要执行该脚本

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;

5 . 代码环境搭建

5.1 订单模块

新建模块：seata-order-service-2001

修改 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>
                <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.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    <!--mysql-druid-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.37</version>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>1.1.10</version>
    </dependency>
    <dependency>
        <groupId>org.mybatis.spring.boot</groupId>
        <artifactId>mybatis-spring-boot-starter</artifactId>
        <version>2.0.0</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>
</dependencies>

编写 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: localhost:8848
  datasource:
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/seata_order?serverTimezone=UTC&useUnicode=true&characterEncoding=utf-8
    username: root
    password: 123456

feign:
  hystrix:
    enabled: false

logging:
  level:
    io:
      seata: info

mybatis:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: com.demo.springcloud.pojo

编写 file.conf 文件

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"

  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

编写 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"

实体类

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);
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