一、简介

之前用多线程模拟2PC事务提交的博客。自己用多线程去解决分布式事务是比较痛苦的。这里介绍一款比较流行的分布式事务框架，阿里的seata。

  1. 本文主要介绍分布式框架的seata（1.4.2）在项目开发中的简单使用。
  2. seata 有四种模式，分别是AT、TCC、Sage、XA。本文使用的是AT模式，其他模式感兴趣的小伙伴可以自己去研究下。
  3. 本文项目结构：springboot 2.2.4.RELEASE + nacos 1.4.2 + seata 1.4.2 + mysql 5.6.45

二、安装和配置

1. nacos下载、安装

nacos的下载安装在这里就不赘述了。下面附上我使用的nacos版本下载地址
nacos 下载地址 https://github.com/alibaba/nacos/releases/tag/1.4.2

2. seata服务安装、配置

2.1 安装

2.2 配置

配置seata 我们可以在安装目录的conf文件夹下找到 README-zh.md 文件，这里分别有 server、client、config-center 三部分的脚本存放路径。

2.2.1 seata-server
  • 访问 server 的脚本存放路径在这里插入图片描述 因为我们使用的是mysql，所以取mysql目录下的sql脚本。
  • 在自己的mysql中新建数据库seata，将上面拿到的sql脚本到数据库中执行即可。
2.2.2 config-center
2.2.2.1 file.conf修改

file.conf文件打开如下：

## transaction log store, only used in seata-server
store {
  ## store mode: file、db、redis
  mode = "file"
  ## rsa decryption public key
  publicKey = ""
  ## file store property
  file {
    ## store location dir
    dir = "sessionStore"
    # branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
    maxBranchSessionSize = 16384
    # globe session size , if exceeded throws exceptions
    maxGlobalSessionSize = 512
    # file buffer size , if exceeded allocate new buffer
    fileWriteBufferCacheSize = 16384
    # when recover batch read size
    sessionReloadReadSize = 100
    # async, sync
    flushDiskMode = async
  }

  ## database store property
  db {
    ## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp)/HikariDataSource(hikari) etc.
    datasource = "druid"
    ## mysql/oracle/postgresql/h2/oceanbase etc.
    dbType = "mysql"
    driverClassName = "com.mysql.jdbc.Driver"
    ## if using mysql to store the data, recommend add rewriteBatchedStatements=true in jdbc connection param
    url = "jdbc:mysql://127.0.0.1:3306/seata?rewriteBatchedStatements=true"
    user = "mysql"
    password = "mysql"
    minConn = 5
    maxConn = 100
    globalTable = "global_table"
    branchTable = "branch_table"
    lockTable = "lock_table"
    queryLimit = 100
    maxWait = 5000
  }

  ## redis store property
  redis {
    ## redis mode: single、sentinel
    mode = "single"
    ## single mode property
    single {
      host = "127.0.0.1"
      port = "6379"
    }
    ## sentinel mode property
    sentinel {
      masterName = ""
      ## such as "10.28.235.65:26379,10.28.235.65:26380,10.28.235.65:26381"
      sentinelHosts = ""
    }
    password = ""
    database = "0"
    minConn = 1
    maxConn = 10
    maxTotal = 100
    queryLimit = 100
  }
}

这里将 mode = "file" 改为 mode = "db",再将db中的配置替换为自己的数据库连接信息

## database store property
  db {
    ## the implement of javax.sql.DataSource, such as DruidDataSource(druid)/BasicDataSource(dbcp)/HikariDataSource(hikari) etc.
    datasource = "druid"
    ## mysql/oracle/postgresql/h2/oceanbase etc.
    dbType = "mysql"
    driverClassName = "com.mysql.jdbc.Driver"
    ## if using mysql to store the data, recommend add rewriteBatchedStatements=true in jdbc connection param
    url = "jdbc:mysql://127.0.0.1:3306/seata?rewriteBatchedStatements=true"
    user = "root"
    password = "123456"
    minConn = 5
    maxConn = 100
    globalTable = "global_table"
    branchTable = "branch_table"
    lockTable = "lock_table"
    queryLimit = 100
    maxWait = 5000
  }
2.2.2.2 registry.conf修改

registry.conf文件打开如下：

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

  nacos {
    application = "seata-server"
    serverAddr = "127.0.0.1:8848"
    group = "SEATA_GROUP"
    namespace = ""
    cluster = "default"
    username = ""
    password = ""
  }
  eureka {
    serviceUrl = "http://localhost:8761/eureka"
    application = "default"
    weight = "1"
  }
  redis {
    serverAddr = "localhost:6379"
    db = 0
    password = ""
    cluster = "default"
    timeout = 0
  }
  zk {
    cluster = "default"
    serverAddr = "127.0.0.1:2181"
    sessionTimeout = 6000
    connectTimeout = 2000
    username = ""
    password = ""
  }
  consul {
    cluster = "default"
    serverAddr = "127.0.0.1:8500"
    aclToken = ""
  }
  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 = "127.0.0.1:8848"
    namespace = ""
    group = "SEATA_GROUP"
    username = ""
    password = ""
    dataId = "seataServer.properties"
  }
  consul {
    serverAddr = "127.0.0.1:8500"
    aclToken = ""
  }
  apollo {
    appId = "seata-server"
    ## apolloConfigService will cover apolloMeta
    apolloMeta = "http://192.168.1.204:8801"
    apolloConfigService = "http://192.168.1.204:8080"
    namespace = "application"
    apolloAccesskeySecret = ""
    cluster = "seata"
  }
  zk {
    serverAddr = "127.0.0.1:2181"
    sessionTimeout = 6000
    connectTimeout = 2000
    username = ""
    password = ""
    nodePath = "/seata/seata.properties"
  }
  etcd3 {
    serverAddr = "http://localhost:2379"
  }
  file {
    name = "file.conf"
  }
}

这里因为我们使用的注册中心和配置中心是nacos，seata推荐的也是nacos type = "nacos" 所以这里不用修改。只要修改下我们的nacos信息就好了，下面是我修改后的

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

  nacos {
    application = "seata-server"
    serverAddr = "127.0.0.1:8848"
    group = "SEATA_GROUP"
    namespace = "17603f04-caab-4789-8bd4-e3f74637d7e9"
    cluster = "default"
    username = "nacos"
    password = "nacos"
  }
}

config {
  # file、nacos 、apollo、zk、consul、etcd3
  type = "nacos"

  nacos {
    serverAddr = "127.0.0.1:8848"
    namespace = "17603f04-caab-4789-8bd4-e3f74637d7e9"
    group = "SEATA_GROUP"
    username = "nacos"
    password = "nacos"
    dataId = "seataServer.properties"
  }
}
2.2.2.3 config.txt

seata1.4.2 中是没有config.txt文件的，需要去 这里取，获取到config.txt后放到如下位置在这里插入图片描述
这个文件需要修改的地方是 store部分，下面是我修改后的store部分

transport.type=TCP
transport.server=NIO
transport.heartbeat=true
transport.enableClientBatchSendRequest=true
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
service.vgroupMapping.my_test_tx_group=default
service.default.grouplist=127.0.0.1:8091
service.enableDegrade=false
service.disableGlobalTransaction=false
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=false
client.rm.tableMetaCheckerInterval=60000
client.rm.sqlParserType=druid
client.rm.reportSuccessEnable=false
client.rm.sagaBranchRegisterEnable=false
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
store.mode=db
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
store.db.datasource=druid
store.db.dbType=mysql
store.db.driverClassName=com.mysql.jdbc.Driver
store.db.url=jdbc:mysql://sel-mysql:3306/seata?useUnicode=true&rewriteBatchedStatements=true
store.db.user=root
store.db.password=xcr101030
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
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
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
log.exceptionRate=100
transport.serialization=seata
transport.compressor=none
metrics.enabled=false
metrics.registryType=compact
metrics.exporterList=prometheus
metrics.exporterPrometheusPort=9898
2.2.2.4 推送配置到nacos

下载 nacos-config.sh 到conf文件夹下,右击空白处打开 Git Base，输入sh nacos-config.sh -h localhost -p 8848 -g SEATA_GROUP -t 0af6e97b-a684-4647-b696-7c6d42aecce7 -u nacos -w nacos 回车即可。

命令注释：-h 后面的是nacos的地址，-p 后面是nacos的端口，-g 后面是组名，-t后面是命名空间的id,在上面修改registry.conf文件的时候都写过，记录一下。 -u -w指定nacos的用户名和密码。

见到下图表示seata配置成功。在这里插入图片描述
打开我们的nacos可以看到seata的配置信息已经添加完成。在这里插入图片描述

2.3 启动seata

到这里我们的seata配置已经完成，有人可能会好奇，不是还有client没有配置吗？别着急，客户端在我们后面用到的时候再去添加。
双击bin/seata-server.bat文件
在这里插入图片描述可以看到，seata服务已经启动，去nacos注册中心看看seata服务是否注册到了nacos。在这里插入图片描述至此，seata的安装、配置已经完成。

3. 项目整合

  • pom依赖
<!-- seata的依赖 -->
<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-seata</artifactId>
    <version>2.2.0.RELEASE</version>
    <exclusions>
        <exclusion>
            <groupId>io.seata</groupId>
            <artifactId>seata-spring-boot-starter</artifactId>
        </exclusion>
        <exclusion>
            <groupId>io.seata</groupId>
            <artifactId>seata-all</artifactId>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupId>io.seata</groupId>
    <artifactId>seata-spring-boot-starter</artifactId>
    <version>1.4.0</version>
</dependency>
<dependency>
    <groupId>io.seata</groupId>
    <artifactId>seata-all</artifactId>
    <version>1.4.0</version>
</dependency>
  • 配置文件
# seata配置
seata:
  enabled: true
  enable-auto-data-source-proxy: true
  tx-service-group: my_test_tx_group
  registry:
    type: nacos
    nacos:
      application: seata-server
      server-addr: 127.0.0.1:8848
      namespace: 17603f04-caab-4789-8bd4-e3f74637d7e9
      group: SEATA_GROUP
      username: nacos
      password: nacos
  config:
    type: nacos
    nacos:
      server-addr: 127.0.0.1:8848
      group: SEATA_GROUP
      username: nacos
      password: nacos
      namespace: 17603f04-caab-4789-8bd4-e3f74637d7e9
  service:
    vgroup-mapping:
      my_test_tx_group: default
    disable-global-transaction: false
  client:
    rm:
      report-success-enable: false
  • 业务代码
@Override
@GlobalTransactional(rollbackFor = Exception.class)
public Integer killUser(Integer num) {
    log.error("一共要杀" + num + "个人");
    int ceil = (int)Math.ceil(num / 2);
    IPage<User> page = new Page<>(1,ceil);
    page = userMapper.selectPage(page, new QueryWrapper<>());
    List<Integer> ids = page.getRecords().stream().map(User::getId).collect(Collectors.toList());
    int currentKillNum = userMapper.deleteBatchIds(ids);
    log.error("自己杀了" + currentKillNum + "个人");

    Integer securityKillNum = esUserClient.killUser(ceil);
    log.error("调用别的服务杀了" + securityKillNum + "个人");

    if(1>0){
        log.error("杀错数量了，需要回滚从新来");
        System.out.println(1/0);
    }
    return currentKillNum + securityKillNum;
}

注意：
1、与我们以前的@Transactional注解不同，这里使用的是@GlobalTransactional注解
2、在每个参与事务的子服务中都需要在数据库加上undo_log这张表，并且需要添加seata的依赖、配置。

# java
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