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一：消息中间件：

• 消息队列RocketMQ版提供的分布式事务消息适用于所有对数据最终一致性有强需求的场景。详细见：www.alibabacloud.com/help/zh/mes…

二：seata

1.seata部署安装

详细见：blog.csdn.net/zhuocailing…

2.seata 使用

现在测试是在note项目和优课资源项目进行测试。本地安装的seata。采用file进行存储。配置和注册到nacos上

2.1 AT 模式

AT：Auto Transaction，基于支持本地ACID事务的关系型数据库，对业务无侵入；

前提

• 基于支持本地 ACID 事务的关系型数据库。
• Java 应用，通过 JDBC 访问数据库。

整体机制

两阶段提交协议的演变：

• 一阶段：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：
  • 提交异步化，非常快速地完成。
  • 回滚通过一阶段的回滚日志进行反向补偿。

2.2 引入依赖

    api("com.alibaba.cloud:spring-cloud-starter-alibaba-seata")
    // 引入下面2个主要是因为在实验阶段发现引入后seata报错。修改undo_log默认的序列化方式。
    //undo_log 默认的序列化方式 jackson，在seata中使用jackson序列化方式会有问题，那么我们修改 kryo 序列化方式就可以解决这个问题。
    api("com.esotericsoftware:kryo:4.0.2")
    api("de.javakaffee:kryo-serializers:0.42")

2.3 增加seata配置

seata:
  enabled: true
  application-id: ${spring.application.name}
  # 事务组的名称，对应service.vgroupMapping.default_tx_group=xxx中配置的default_tx_group
  tx-service-group: default_tx_group
  # 配置事务组与集群的对应关系
  service:
    vgroup-mapping:
      # default_tx_group为事务组的名称，default为集群名称(与registry.conf中的一致)
      default_tx_group: default
    disable-global-transaction: false
  registry:
    type: nacos
    nacos:
      application: seata-server
      server-addr: 10.0.11.20:8848
      group: SEATA_GROUP
      namespace: qlteacher-fat
      username: nacos
      password: nacos
      # registry.conf中，配置cluster名称
      cluster: default
  config:
    type: nacos
    nacos:
      server-addr: 10.0.11.20:8848
      group: SEATA_GROUP
      namespace: qlteacher-fat
      username: nacos
      password: nacos
      # nacos配置中心配置的dataId
      data-id: seataServer.properties

2.4 配置seataServer.properties

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

#Transaction routing rules configuration, only for the client
service.vgroupMapping.default_tx_group=default
#If you use a registry, you can ignore it
service.default.grouplist=127.0.0.1:8091
service.enableDegrade=false
service.disableGlobalTransaction=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=kryo
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

#Transaction storage configuration, only for the server. The file, DB, and redis configuration values are optional.
store.mode=file
store.lock.mode=file
store.session.mode=file
#Used for password encryption
store.publicKey=

#If `store.mode,store.lock.mode,store.session.mode` are not equal to `file`, you can remove the configuration block.
store.file.dir=file_store/data
store.file.maxBranchSessionSize=16384
store.file.maxGlobalSessionSize=512
store.file.fileWriteBufferCacheSize=16384
store.file.flushDiskMode=async
store.file.sessionReloadReadSize=100

#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.jdbc.Driver
store.db.url=jdbc:mysql://127.0.0.1:3306/seata?useUnicode=true&rewriteBatchedStatements=true
store.db.user=username
store.db.password=password
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

#These configurations are required if the `store mode` is `redis`. If `store.mode,store.lock.mode,store.session.mode` are not equal to `redis`, you can remove the configuration block.
store.redis.mode=single
store.redis.single.host=127.0.0.1
store.redis.single.port=6379
store.redis.sentinel.masterName=
store.redis.sentinel.sentinelHosts=
store.redis.maxConn=10
store.redis.minConn=1
store.redis.maxTotal=100
store.redis.database=0
store.redis.password=
store.redis.queryLimit=100

#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

#Metrics configuration, only for the server
metrics.enabled=false
metrics.registryType=compact
metrics.exporterList=prometheus
metrics.exporterPrometheusPort=9898

2.5 创建undo_log数据库表

需要在note服务和优课资源服务 都创建一个undo_log表

CREATE TABLE IF NOT EXISTS `undo_log`
(
    `branch_id`     BIGINT(20)   NOT NULL COMMENT 'branch transaction id',
    `xid`           VARCHAR(100) 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';

2.6 测试

只需要在需要分布式事务的地方增加 @GlobalTransactional注解即可 下面测试通过dubbo调用note。新增成功。然后本服务又出现异常。经过测试，note服务会进行回滚数据。测试成功。

    /**
     * 增加笔记
     *
     * @param noteParam 增加笔记参数
     * @return 是否增加成功
     */
    @Override
    @GlobalTransactional(rollbackFor = Exception.class)
    public boolean addNote(NoteAddParam noteParam) {
        NoteDTO noteDTO = NoteCovert.INSTANCE.addParamToDto(noteParam);
        String sourceNoteId = noteDTO.getSourceNoteId();
        if (StringUtils.hasLength(sourceNoteId)) {
            boolean existNote = noteManager.existNote(sourceNoteId);
            if (!existNote) {
                throw new ExcellentResourceException(ExcellentResourceResultEnum.NOTE_NOT_EXIT_ERROR);
            }
        }
        noteManager.addNote(noteDTO);
        System.err.println("RootContext.getXID():" + RootContext.getXID());
        System.out.println(1/0);
        return true;
    }