在分布式系统中，解决数据一致性问题都比较麻烦，虽然已经有很多基于消息中间件回调的方案，今天提供一个比较优秀的方案分布式事务Easta，这只是个入门教程，后续跟进

我的项目组合SpringBoot +MyBatis+Dubbo+Easta+Nacos

SpringBoot +MyBatis+Dubbo这个我就不在过多解释了，网上有很多解释
今天主要说的是Easta+Nacos

Nacos

阿里巴巴出品的一个更易于构建云原生应用的动态服务发现、配置管理和服务管理平台。可以替代zookeeper,这里采用Nacos主要是Easta的官方提供的建议使用，也是用于Dubbo的注册服务，至于和zookeeper的区别，暂时没有研究到后期更近。

Nacos 安装

官方安装说明很简单,

下载最新包并解压
运行

cd nacos/bin 
sh startup.sh -m standalone

好了这就运行了Nacos服务，通过info提示你可以打http://127.0.0.1:8848/nacos/index.html能够看到Nacos的服务后台

seata

2019 年 1 月，阿里巴巴中间件团队发起了开源项目 Fescar（Fast & EaSy Commit And Rollback），后来改名叫seata了，和社区一起共建开源分布式事务解决方案。Fescar 的愿景是让分布式事务的使用像本地事务的使用一样，简单和高效，并逐步解决开发者们遇到的分布式事务方面的所有难题。先上架构图

image.png

事务协调器（TC）：维护全局和分支事务的状态，驱动全局提交或回滚。（这个是一个总的事务调度和管理，他主要管理每个分支事务，只要分支事务中有一个事务发生回滚，他就会调动所有的其他分支事务回滚，这个分支事务其实就是其他微服务）
Transaction Manager（TM）：定义全局事务的范围：开始全局事务，提交或回滚全局事务。（这个其实就是分布式事务的首发事务，他是会注册到TC里面的，也就是这条分布式事务头）
资源管理器（RM）：管理分支事务的资源，与TC通信以注册分支事务和报告分支事务的状态，并驱动分支事务提交或回滚。（这个其实就是各个微服务上的普遍事务，只不过事务的提交是有RM来控制）

安装

先下载安装包,解压后进入bin 目录运行 sh seata-server.sh -p 8091 -h 127.0.0.1 -m file 打开服务也就是TC
安装依赖

 <!--        dubbo相关依赖-->
        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-dependencies-bom</artifactId>
            <version>${dubbo.version}</version>
            <type>pom</type>
            <scope>import</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-spring-boot-starter</artifactId>
            <version>2.7.1</version>
        </dependency>

        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo</artifactId>
            <version>2.7.1</version>
        </dependency>

        <dependency>
            <groupId>org.apache.dubbo</groupId>
            <artifactId>dubbo-registry-nacos</artifactId>
            <version>2.7.1</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba.nacos</groupId>
            <artifactId>nacos-client</artifactId>
            <version>1.0.0</version>
        </dependency>

        <dependency>
            <groupId>io.seata</groupId>
            <artifactId>seata-all</artifactId>
            <version>0.6.1</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.1.17</version>
        </dependency>

application.properties

server.port=8082
dubbo.application.name=dubbo-registry-zookeeper-provider-sample
## 特别注意dubbo的注册服务为nacos
dubbo.registry.address=nacos://192.168.50.86:8848
dubbo.protocol.name=dubbo
## Random port
dubbo.protocol.port=20881
dubbo.consumer.check=false
dubbo.application.qosEnable=false

spring.datasource.url=jdbc:mysql://rm-m5e15q2904j706p79io.mysql.rds.aliyuncs.com:3306/eosplaygametest
spring.datasource.username=XXXX
spring.datasource.password=XXXXX
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

在resource里添加file.conf和registry.conf

image.png

file.conf内容我直接拷贝官网DEMO的配置，具体每个配置参数并不太了解，后续跟进

transport {
  # tcp udt unix-domain-socket
  type = "TCP"
  #NIO NATIVE
  server = "NIO"
  #enable heartbeat
  heartbeat = true
  #thread factory for netty
  thread-factory {
    boss-thread-prefix = "NettyBoss"
    worker-thread-prefix = "NettyServerNIOWorker"
    server-executor-thread-prefix = "NettyServerBizHandler"
    share-boss-worker = false
    client-selector-thread-prefix = "NettyClientSelector"
    client-selector-thread-size = 1
    client-worker-thread-prefix = "NettyClientWorkerThread"
    # netty boss thread size,will not be used for UDT
    boss-thread-size = 1
    #auto default pin or 8
    worker-thread-size = 8
  }
}

service {
  #vgroup->rgroup
  vgroup_mapping.my_test_tx_group = "default"
  #only support single node
  default.grouplist = "127.0.0.1:8091"
  #degrade current not support
  enableDegrade = false
  #disable
  disable = false
}

client {
  async.commit.buffer.limit = 10000
  lock {
    retry.internal = 10
    retry.times = 30
  }
}
## transaction log store
store {
  ## store mode: file、db
  mode = "file"

  ## file store
  file {
    dir = "file_store/data"

    # branch session size , if exceeded first try compress lockkey, still exceeded throws exceptions
    max-branch-session-size = 16384
    # globe session size , if exceeded throws exceptions
    max-global-session-size = 512
    # file buffer size , if exceeded allocate new buffer
    file-write-buffer-cache-size = 16384
    # when recover batch read size
    session.reload.read_size = 100
  }

  ## database store
  db {
    driver_class = ""
    url = ""
    user = ""
    password = ""
  }
}

registry.conf 也是后续跟进

registry {
  # file nacos
  type = "file"

  nacos {
    serverAddr = "localhost"
    namespace = "public"
    cluster = "default"
  }
  file {
    name = "file.conf"
  }
}

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

  file {
    name = "file.conf"
  }
}

以上配置好后需要在数据源里写一个配置类

7904809C-149D-4AB1-A8CE-F108A5157914.png


/**
 * @Author: heshouyou
 * @Description  seata global configuration
 * @Date Created in 2019/1/24 10:28
 */
@Configuration
public class SeataAutoConfig {

    /**
     * autowired datasource config
     */
    @Autowired
    private DataSourceProperties dataSourceProperties;

    /**
     * init durid datasource
     *
     * @Return: druidDataSource  datasource instance
     */
    @Bean
    @Primary
    public DruidDataSource druidDataSource(){
        DruidDataSource druidDataSource = new DruidDataSource();
        druidDataSource.setUrl(dataSourceProperties.getUrl());
        druidDataSource.setUsername(dataSourceProperties.getUsername());
        druidDataSource.setPassword(dataSourceProperties.getPassword());
        druidDataSource.setDriverClassName(dataSourceProperties.getDriverClassName());
        druidDataSource.setInitialSize(0);
        druidDataSource.setMaxActive(180);
        druidDataSource.setMaxWait(60000);
        druidDataSource.setMinIdle(0);
        druidDataSource.setValidationQuery("Select 1 from DUAL");
        druidDataSource.setTestOnBorrow(false);
        druidDataSource.setTestOnReturn(false);
        druidDataSource.setTestWhileIdle(true);
        druidDataSource.setTimeBetweenEvictionRunsMillis(60000);
        druidDataSource.setMinEvictableIdleTimeMillis(25200000);
        druidDataSource.setRemoveAbandoned(true);
        druidDataSource.setRemoveAbandonedTimeout(1800);
        druidDataSource.setLogAbandoned(true);
        return druidDataSource;
    }

    /**
     * init datasource proxy
     * @Param: druidDataSource  datasource bean instance
     * @Return: DataSourceProxy  datasource proxy
     */
    @Bean
    public DataSourceProxy dataSourceProxy(DruidDataSource druidDataSource){
        return new DataSourceProxy(druidDataSource);
    }

    /**
     * init mybatis sqlSessionFactory.   这里主要是定义了 一个代理 类 用来代理mybatis, 应为目前就用到mybatis
     * @Param: dataSourceProxy  datasource proxy
     * @Return: DataSourceProxy  datasource proxy
     */
    @Bean
    public SqlSessionFactory sqlSessionFactory(DataSourceProxy dataSourceProxy) throws Exception {
        SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
        factoryBean.setDataSource(dataSourceProxy);
        factoryBean.setMapperLocations(new PathMatchingResourcePatternResolver()
                .getResources("classpath*:/mapper/*.xml"));
        factoryBean.setTransactionFactory(new JdbcTransactionFactory());
        return factoryBean.getObject();
    }

    /**
     * init global transaction scanner
     *
     * @Return: GlobalTransactionScanner
     */
    @Bean
    public GlobalTransactionScanner globalTransactionScanner(){
        return new GlobalTransactionScanner("order-gts-fescar-example", "my_test_tx_group");
    }
}

使用时只需要添加注解@GlobalTransactional(timeoutMills = 300000, name = "dubbo-gts-fescar-example")

@Service
@RestController
public class TestController {
    final Logger logger = LoggerFactory.getLogger(getClass());
    @Reference
    UserSerivce user;
    @Autowired
    user_roleMapper roleMapper;
    @GlobalTransactional(timeoutMills = 300000, name = "dubbo-gts-fescar-example")
    @RequestMapping("/t")
    public void TestData() throws RuntimeException {
        String n= user.GetUserName();
        logger.info("插入入了"+n);
        throw new RuntimeException("ssssss");
    }
}

其中@GlobalTransactional 就是 TM ，分布式事务从TestData() 开始来看下GetUserName调用的微服务方法

@Service
public class User implements UserSerivce {
    final Logger logger = LoggerFactory.getLogger(getClass());
    @Autowired
    user_roleMapper roleMapper;
    public String GetUserName(){
        user_role role= new user_role();
        role.setGuid("2222");
        role.setIssystem("1");
        role.setName("222");
        role.setTitle("bbbbb");
        int i= roleMapper.insert(role);
        return  ""+I;
    }
}

补充一下
需要在数据库中添加一个表,不然Easta会报错

-- ----------------------------
-- Table structure for undo_log
-- 注意此处0.3.0+ 增加唯一索引 ux_undo_log
-- ----------------------------
DROP TABLE IF EXISTS `undo_log`;
CREATE TABLE `undo_log` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `branch_id` bigint(20) NOT NULL,
  `xid` varchar(100) NOT NULL,
  `rollback_info` longblob NOT NULL,
  `log_status` int(11) NOT NULL,
  `log_created` datetime NOT NULL,
  `log_modified` datetime NOT NULL,
  `ext` varchar(100) DEFAULT NULL,
  PRIMARY KEY (`id`),
  UNIQUE KEY `ux_undo_log` (`xid`,`branch_id`)
) ENGINE=InnoDB AUTO_INCREMENT=94 DEFAULT CHARSET=utf8;

-- ----------------------------
-- Records of undo_log
-- ----------------------------
SET FOREIGN_KEY_CHECKS=1;

代码运行截图说明

image.png

看下结果Info

Branch Rollbacking: 192.168.50.86:8091:2014816472 2014816473 jdbc:mysql://rm-m5e15q2904j706p79io.mysql.rds.aliyuncs.com:3306/eosplaygametest
io.seata.config.FileConfiguration        : Could not found property transaction.undo.data.validation, try to use default value instead.
i.s.rm.datasource.undo.UndoLogManager    : xid 192.168.50.86:8091:2014816472 branch 2014816473, undo_log deleted with GlobalFinished
 io.seata.rm.AbstractRMHandler            : Branch Rollbacked result: PhaseTwo_Rollbacked
 io.seata.core.rpc.netty.RmRpcClient      : RmRpcClient sendResponse xid=192.168.50.86:8091:2014816472,branchId=2014816473,branchStatus=PhaseTwo_Rollbacked,result code =Success,getMsg =null

可以看到 Branch Rollbacking 分支事务成功回滚了

注意一下这个微服务的提供方法并不需做任何修改这个方法会自动被（RM管理）

@Service
public class User implements UserSerivce {
    final Logger logger = LoggerFactory.getLogger(getClass());
    @Autowired
    user_roleMapper roleMapper;
    public String GetUserName(){
        user_role role= new user_role();
        role.setGuid("2222");
        role.setIssystem("1");
        role.setName("222");
        role.setTitle("bbbbb");
        int i= roleMapper.insert(role);
        return  ""+i;
    }
}

重要的事情说三遍
遵循JAVA 业务至上原则

代码没有侵入性

如果需要的话补上ZK篇O(∩_∩)O哈哈~ 未完待续

SpringBoot +MyBatis+Dubbo+Easta+Nacos 解决老大难问题

SpringBoot +MyBatis+Dubbo+Easta+Nacos 解决老大难问题

我的项目组合SpringBoot +MyBatis+Dubbo+Easta+Nacos

Nacos

Nacos 安装

seata

安装

以上配置好后需要在数据源里写一个配置类

代码没有侵入性

代码没有侵入性

代码没有侵入性

SpringBoot +MyBatis+Dubbo+Easta+Nacos 解决老大难问题

我的项目组合SpringBoot +MyBatis+Dubbo+Easta+Nacos

Nacos

Nacos 安装

seata

安装

以上配置好后需要 在数据源里写一个配置类

代码没有侵入性

代码没有侵入性

代码没有侵入性

以上配置好后需要在数据源里写一个配置类