seata的架构

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seata是无状态，低耦合的微服务，为了达到回滚的状态需要建立seata的服务

1、下载seata 服务

http://seata.io/zh-cn/blog/download.html
本文下载的是 1.4.2
下载后解压的目录

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2、修改seata配置文件

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2.1、配置注册配置文件

本文由于没有架设集群采用file 模式
registry.conf

registry {
  # file 、nacos 、eureka、redis、zk、consul、etcd3、sofa
  type = "eureka"  # 改为 eureka

  eureka { # 修改eureka 数据块中的数据
    serviceUrl = "http://192.168.1.2:9876/eureka" # eureka服务的地址
    application = "seata-server" # seata 的显示名
    weight = "1"
  }
}

file.conf
将 file.conf 和 file.conf.example 互换名称

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并在 新 的 file.conf 中加入

service {
  #transaction service group mapping
  # 注意：1.2.0 版本（或更早的版本） 已经将 ‘vgroup_mapping’ 改为 ‘vgroupMapping’
  vgroupMapping.fsp_tx_group = "default"
  #only support when registry.type=file, please don't set multiple addresses
  default.grouplist = "127.0.0.1:8091"
  #degrade, current not support 降级处理
  enableDegrade = false
  #disable seata 是否开启本地事务
  disableGlobalTransaction = false
}

此代码块和 server 同级

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此时 启动 seata server 即可

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3、更新业务代码配置

3.1 业务代码中引入依赖

pom.xml

   <!-- Seata -->
        <dependency>
            <groupId>io.seata</groupId>
            <artifactId>seata-spring-boot-starter</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>com.alibaba</groupId>
                    <artifactId>druid</artifactId>
                </exclusion>
            </exclusions>
            <version>1.3.0</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-alibaba-seata</artifactId>
            <exclusions>
                <exclusion>
                    <groupId>io.seata</groupId>
                    <artifactId>seata-spring-boot-starter</artifactId>
                </exclusion>
            </exclusions>
            <version>2.2.0.RELEASE</version>
        </dependency>

3.2 修改 yml文件

# seata的配置
seata: 
  enabled: true
  application-id: seata-server
  tx-service-group: default  # 此时不能变化，否则会出现io.seata.common.exception.FrameworkException: No available service
  enable-auto-data-source-proxy: true
  use-jdk-proxy: false
  service:
    vgroup-mapping:
      default: seata-server
    enable-degrade: false
    disable-global-transaction: false
  registry:
    type: eureka
    eureka:
      weight: 1
      service-url: http://192.168.1.2:9876/eureka/

# eureka
eureka:
  client:
    service-url:
      defaultZone: http://192.168.1.2:9876/eureka/
    enabled: true

在serviceImp上加入 注解

    @GlobalTransactional

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在 application中加入
@EnableAutoDataSourceProxy

@MapperScan("com.test.usr.mapper")
@SpringBootApplication()
@EnableEurekaClient
@EnableFeignClients
@EnableAutoDataSourceProxy
public class TestApplication {

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

}

3.3、在数据库中加入 undo_log

如果你需要用 seata 这个表必须加入
mysql

CREATE TABLE IF NOT EXISTS `undo_log`
(
    `branch_id`     BIGINT       NOT NULL COMMENT 'branch transaction id',
    `xid`           VARCHAR(128) NOT NULL COMMENT 'global transaction id',
    `context`       VARCHAR(128) NOT NULL COMMENT 'undo_log context,such as serialization',
    `rollback_info` LONGBLOB     NOT NULL COMMENT 'rollback info',
    `log_status`    INT(11)      NOT NULL COMMENT '0:normal status,1:defense status',
    `log_created`   DATETIME(6)  NOT NULL COMMENT 'create datetime',
    `log_modified`  DATETIME(6)  NOT NULL COMMENT 'modify datetime',
    UNIQUE KEY `ux_undo_log` (`xid`, `branch_id`)
) ENGINE = InnoDB
  AUTO_INCREMENT = 1
  DEFAULT CHARSET = utf8 COMMENT ='AT transaction mode undo table';

启动 seata服务器

启动成功：

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后台启动 seata
nohup ./bin/seata-server.sh -p 8091 -h 127.0.0.1 -m file >nohup.out 2>1 &