seata版本为1.5.2,要关注版本,因为版本之间的差距很大.
官网地址:http://seata.io/zh-cn/
server源码:https://github.com/seata/seata
seata-server下载:
百度下载
链接：https://pan.baidu.com/s/1eilbSI0YdmupHYI7FroTsw
提取码：biam
github下载:
https://github.com/seata/seata/releases
nacos下载地址：https://github.com/alibaba/nacos/releases
百度网盘下载地址
链接：https://pan.baidu.com/s/1I4Z-vVrTTch6p4Z1FhIkOQ
提取码：g7hg
实例代码:
https://gitee.com/zhangjijige/springcloudalibaba.git
代码是借鉴来的,稍微改了一下
本文使用的AT的方式实现分布式事务,也是最经常使用一种模式,至于其余的模式这里就不阐述了,配置中心使用nacos,seata-server(事务协调者)使用mysql的方式存储,性能会有写损失,但是稳定性好一些,也是比较常用的方式,什么是seata都可以取官网了解一下.
1.创建数据库
image.png
sql语句在项目中
2.创建seata-server(事务协调者)
配置文件
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
#1.5提供了可视化界面,用户名和密码
console:
user:
username: seata
password: seata
seata:
config:
# support: nacos, consul, apollo, zk, etcd3
type: nacos
nacos:
server-addr: 127.0.0.1:8848
namespace:
group: SEATA_GROUP
username:
password:
##if use MSE Nacos with auth, mutex with username/password attribute
#access-key: ""
#secret-key: ""
data-id: seataServer.properties
registry:
# support: nacos, eureka, redis, zk, consul, etcd3, sofa
type: nacos
nacos:
application: seata-server
server-addr: 127.0.0.1:8848
group: SEATA_GROUP
namespace:
cluster: default(这里后续提到很重要的配置)
username:
password:
##if use MSE Nacos with auth, mutex with username/password attribute
#access-key: ""
#secret-key: ""
security:
secretKey: SeataSecretKey0c382ef121d778043159209298fd40bf3850a017
tokenValidityInMilliseconds: 1800000
ignore:
urls: /,/**/*.css,/**/*.js,/**/*.html,/**/*.map,/**/*.svg,/**/*.png,/**/*.ico,/console-fe/public/**,/api/v1/auth/login
启动seata-server
seata-server.bat
3.启动nacos
注意在seata-server的配置文件中,data-id: seataServer.properties配置
nacos的启动本文就是使用单机启动
startup.cmd -m standalone
nacos的命名空间就使用默认的public,在配置的namespace为空就可以了
创建配置
image.png
service.vgroupMapping.default_tx_group=default这个配置很重要
#这个很重要,要不然事务不起作用
#default_tx_group和default,defaule是seata-server中 registry:中cluster的数值
#default_tx_group是资源服务,就是写业务的服务的配置 tx-service-group: default_tx_group
service.vgroupMapping.default_tx_group=default
service.enableDegrade=false
service.disableGlobalTransaction=false
#Transaction storage configuration, only for the server. The file, DB, and redis configuration values are optional.
store.mode=db
store.lock.mode=db
store.session.mode=db
#Used for password encryption
#store.publicKey=
#These configurations are required if the `store mode` is `db`. If `store.mode,store.lock.mode,store.session.mode` are not equal to `db`, you can remove the configuration block.
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/seata?useUnicode=true&rewriteBatchedStatements=true
store.db.user=root
store.db.password=root
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
#Transaction rule configuration, only for the server
server.recovery.committingRetryPeriod=1000
server.recovery.asynCommittingRetryPeriod=1000
server.recovery.rollbackingRetryPeriod=1000
server.recovery.timeoutRetryPeriod=1000
server.maxCommitRetryTimeout=-1
server.maxRollbackRetryTimeout=-1
server.rollbackRetryTimeoutUnlockEnable=false
server.distributedLockExpireTime=10000
server.xaerNotaRetryTimeout=60000
server.session.branchAsyncQueueSize=5000
server.session.enableBranchAsyncRemove=false
#Transaction rule configuration, only for the client
client.rm.asyncCommitBufferLimit=10000
client.rm.lock.retryInterval=10
client.rm.lock.retryTimes=30
client.rm.lock.retryPolicyBranchRollbackOnConflict=true
client.rm.reportRetryCount=5
client.rm.tableMetaCheckEnable=true
client.rm.tableMetaCheckerInterval=60000
client.rm.sqlParserType=druid
client.rm.reportSuccessEnable=false
client.rm.sagaBranchRegisterEnable=false
client.rm.sagaJsonParser=fastjson
client.rm.tccActionInterceptorOrder=-2147482648
client.tm.commitRetryCount=5
client.tm.rollbackRetryCount=5
client.tm.defaultGlobalTransactionTimeout=60000
client.tm.degradeCheck=false
client.tm.degradeCheckAllowTimes=10
client.tm.degradeCheckPeriod=2000
client.tm.interceptorOrder=-2147482648
client.undo.dataValidation=true
client.undo.logSerialization=jackson
client.undo.onlyCareUpdateColumns=true
server.undo.logSaveDays=7
server.undo.logDeletePeriod=86400000
client.undo.logTable=undo_log
client.undo.compress.enable=true
client.undo.compress.type=zip
client.undo.compress.threshold=64k
#For TCC transaction mode
tcc.fence.logTableName=tcc_fence_log
tcc.fence.cleanPeriod=1h
#Log rule configuration, for client and server
log.exceptionRate=100
#Metrics configuration, only for the server
metrics.enabled=false
metrics.registryType=compact
metrics.exporterList=prometheus
metrics.exporterPrometheusPort=9898
#For details about configuration items, see https://seata.io/zh-cn/docs/user/configurations.html
#Transport configuration, for client and server
transport.type=TCP
transport.server=NIO
transport.heartbeat=true
transport.enableTmClientBatchSendRequest=false
transport.enableRmClientBatchSendRequest=true
transport.enableTcServerBatchSendResponse=false
transport.rpcRmRequestTimeout=30000
transport.rpcTmRequestTimeout=30000
transport.rpcTcRequestTimeout=30000
transport.threadFactory.bossThreadPrefix=NettyBoss
transport.threadFactory.workerThreadPrefix=NettyServerNIOWorker
transport.threadFactory.serverExecutorThreadPrefix=NettyServerBizHandler
transport.threadFactory.shareBossWorker=false
transport.threadFactory.clientSelectorThreadPrefix=NettyClientSelector
transport.threadFactory.clientSelectorThreadSize=1
transport.threadFactory.clientWorkerThreadPrefix=NettyClientWorkerThread
transport.threadFactory.bossThreadSize=1
transport.threadFactory.workerThreadSize=default
transport.shutdown.wait=3
transport.serialization=seata
transport.compressor=none
3.资源服务(业务服务)
这里要说明的是seata的配置了 nacos,项目本身也配置了nacos,两个配置都是需要的,
注意seata-server的nacos的group和资源服务的group要保持一致,具体看git上的项目的配置,没有需要特殊说明的.
4.使用
AT模式的使用,还是比较简单的,只需要在服务调用的发起方标注
@GlobalTransactional注解即可
这里举例要回滚的
seata.controller.TestController#testCommit方法被@GlobalTransactional标注
更新stock表
productService.reduceStock(id, totalAmount);
新增订单
orderService.save(orders);
新增订单的方法写了一个 10/0的代码,报错误
方法调用前
image.png
debug到orderService.save(orders);
image.png
此时stock表发生变化
image.png
由86变成84
看一下undolog表的rollback_info字段数据,存储了原数据和修改后的数据
{"@class":"io.seata.rm.datasource.undo.BranchUndoLog","xid":"172.17.171.135:8091:4602985123575644297","branchId":4602985123575644299,"sqlUndoLogs":["java.util.ArrayList",[{"@class":"io.seata.rm.datasource.undo.SQLUndoLog","sqlType":"UPDATE","tableName":"stock","beforeImage":{"@class":"io.seata.rm.datasource.sql.struct.TableRecords","tableName":"stock","rows":["java.util.ArrayList",[{"@class":"io.seata.rm.datasource.sql.struct.Row","fields":["java.util.ArrayList",[{"@class":"io.seata.rm.datasource.sql.struct.Field","name":"id","keyType":"PRIMARY_KEY","type":4,"value":1},{"@class":"io.seata.rm.datasource.sql.struct.Field","name":"count","keyType":"NULL","type":4,"value":86}]]}]]},"afterImage":{"@class":"io.seata.rm.datasource.sql.struct.TableRecords","tableName":"stock","rows":["java.util.ArrayList",[{"@class":"io.seata.rm.datasource.sql.struct.Row","fields":["java.util.ArrayList",[{"@class":"io.seata.rm.datasource.sql.struct.Field","name":"id","keyType":"PRIMARY_KEY","type":4,"value":1},{"@class":"io.seata.rm.datasource.sql.struct.Field","name":"count","keyType":"NULL","type":4,"value":84}]]}]]}}]]}
继续调用orderService.save(orders);方法会报错误,整个事务回滚,stock表就会归滚到86
这样分布式事务结束.
还有很多的情况,比如人为的把stoke的数据改一下, 86 全局事务改为84,人为改为80,当事务回滚的时候,数据怎么恢复,还有全局事务没有提交的情况下,其实数据是已经发生了变化,那这个时候,另一个事务读取数据是多少后续的文章会分析.
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