微服务集成seata完成分布式事务，解决数据不一致问题

细心的盆友可能已经发现了，我们的跨行转账并没有保证数据一致性，比如小明扣除了100，但是因为各种问题小红在添加100金额的时候遇到了异常，这个时候数据就出现不一致性

我们可以选择seata来进行分布式事务杜绝这种现象的发生

之前的教程：https://www.cnblogs.com/leafstar/p/17641407.html

1.我使用的是seata1.7版本，可以从官网很简单下载到，不同版本配置可能略有不同

2.修改seata配置conf/application.yml

我的配置如下：

server:
  port: 7091

spring:
  application:
    name: seata-server

logging:
  config: classpath:logback-spring.xml
  file:
    path: ${user.home}/logs/seata
  extend:
    logstash-appender:
      destination: 127.0.0.1:4560
    kafka-appender:
      bootstrap-servers: 127.0.0.1:9092
      topic: logback_to_logstash

console:
  user:
    username: seata
    password: seata

seata:
  # nacos配置
  config:
    type: nacos
    nacos:
      server-addr: 127.0.0.1:8848
      namespace:
      group: SEATA_GROUP
      username:
      password:
      context-path:
      data-id: seataServer.properties
      ##if use MSE Nacos with auth, mutex with username/password attribute
      #access-key:
      #secret-key:
  registry:
    # nacos配置
    type: nacos
    nacos:
      application: seata-server
      server-addr: 127.0.0.1:8848
      group: SEATA_GROUP
      namespace:
      cluster: default
      username:
      password:
      context-path:
      ##if use MSE Nacos with auth, mutex with username/password attribute
      #access-key:
      #secret-key:
#  server:
#    service-port: 8091 #If not configured, the default is '${server.port} + 1000'
  security:
    secretKey: SeataSecretKey0c382ef121d778043159209298fd40bf3850a017
    tokenValidityInMilliseconds: 1800000
    ignore:
      urls: /,/**/*.css,/**/*.js,/**/*.html,/**/*.map,/**/*.svg,/**/*.png,/**/*.jpeg,/**/*.ico,/api/v1/auth/login

3.通过bin目录下的脚本启动seata

4.在需要发起全局事务的数据库中创建undo_log表，语句如下

SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;

-- ----------------------------
-- Table structure for undo_log
-- ----------------------------
DROP TABLE IF EXISTS `undo_log`;
CREATE TABLE `undo_log`  (
  `id` bigint NOT NULL AUTO_INCREMENT,
  `branch_id` bigint NOT NULL,
  `xid` varchar(100) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NOT NULL,
  `context` varchar(128) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NOT NULL,
  `rollback_info` longblob NOT NULL,
  `log_status` int NOT NULL,
  `log_created` datetime NOT NULL,
  `log_modified` datetime NOT NULL,
  `ext` varchar(100) CHARACTER SET utf8mb3 COLLATE utf8mb3_general_ci NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE,
  UNIQUE INDEX `ux_undo_log`(`xid` ASC, `branch_id` ASC) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 16 CHARACTER SET = utf8mb3 COLLATE = utf8mb3_general_ci ROW_FORMAT = Dynamic;

-- ----------------------------
-- Records of undo_log
-- ----------------------------

SET FOREIGN_KEY_CHECKS = 1;

将seata目录下seata\script\server\db的mysql.sql脚本文件导入数据库中，最终效果如下

5.仅在需要发起全局事务的服务中添加依赖

<dependency>
    <groupId>io.seata</groupId>
    <artifactId>seata-spring-boot-starter</artifactId>
    <version>1.4.2</version>
 </dependency>

6.仅在需要发起全局事务的服务中添加以下配置即可

seata:
  enabled: true
  application-id: ccxi-abc
  tx-service-group: ccxi_tx_group
  service:
    vgroup-mapping:
      ccxi_tx_group: default
  registry:
    type: nacos
    nacos:
      server-addr: 127.0.0.1:8848
      namespace: public
      group: SEATA_GROUP
      application: seata-server

7.在nacos中添加seataServer.properties配置如下图

配置如下

#Transaction storage configuration, only for the server.
store.mode=db
store.lock.mode=db
store.session.mode=db

#These configurations are required if the `store mode` is `db`.
store.db.datasource=druid
store.db.dbType=mysql
store.db.driverClassName=com.mysql.cj.jdbc.Driver
store.db.url=jdbc:mysql://127.0.0.1:3306/bank1?useSSL=false&useUnicode=true&rewriteBatchedStatements=true
store.db.user=root
store.db.password=123456
store.db.minConn=5
store.db.maxConn=30
store.db.globalTable=global_table
store.db.branchTable=branch_table
store.db.distributedLockTable=distributed_lock
store.db.queryLimit=100
store.db.lockTable=lock_table
store.db.maxWait=5000

将数据库信息改成自己的信息

8.在准备开启全局事务的接口下添加注解

 9.报错如下，execute executeAutoCommitTrue error:[xid:192.168.74.1:8091:8413149769213006417]get table meta failed, please check whether the table `account` exists.

主要是因为数据表中没有设置主键，在此为了简单，我们选择将name变成主键

10.重启项目并调用转账接口，可以看到seata的服务面板显示如下

11现在我们来模拟小红收款异常，故意在这里抛出异常并等待20秒，重启服务

12.调用转账接口

可以看到，undo_log已经被写入一条数据，抛出异常后，这条数据就没了，同时我们对小明的转账修改也被撤销

13.等待的20秒内，小明数据被修改

抛出异常后，小明的数据又被改回来了

 14.seata控制台显示回滚成功

 15.至此，我们完成了分布式事务的简单使用，这个系列的实战教程也就结束了