seata分佈式事務--看這一篇就夠了~

本人小白哈，如果寫的有錯誤或者不對的歡迎留言評論。

首次接觸分佈式事務，在選型的時候並沒有選中lcn,而且選擇了阿里開源的 seata框架，看了很多文章說是，無侵入性，咱也不知道，咱也沒敢問。

seata的wiki文檔【seataWIKI文檔】

seata的官方demo【seata官方DEMO】

我是想着第一次接觸，就不用官網的DEMO示例了，先自己搭建一個吧~(入坑了)

項目是用springcloud+mybatisplus+seata+druid+feign集成的，

spring cloud-->2.1.6.RELEASE 版本：Greenwich.SR2

mybatis plus -->3.1.0

seata -->0.7.1

druid-->1.1.2

feign組件是openfeign

項目長成這個艹性，別噴我，我是自己瞎玩的，你要是噴我我估計也要懟你哦，哈哈

其實項目還有很多不完善的地方，還沒時間去優化,下一步會加上分佈式鎖，想用readLock，哈哈

第一個模塊示例圖:目的是想着只新增maven依賴，還有一些公共配置，現在好像做反了。

pom.xml文件

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
    <dependency>
        <groupId>io.seata</groupId>
        <artifactId>seata-all</artifactId>
        <version>${seata.version}</version>
    </dependency>
    <dependency>
        <groupId>io.seata</groupId>
        <artifactId>seata-core</artifactId>
        <version>${seata.version}</version>
    </dependency>
    <dependency>
        <groupId>com.alibaba.fescar</groupId>
        <artifactId>fescar-rm-datasource</artifactId>
        <version>${fescar-rm.version}</version>
    </dependency>
    <dependency>
        <groupId>com.alibaba.fescar</groupId>
        <artifactId>fescar-spring</artifactId>
        <version>${fescar-rm.version}</version>
    </dependency>


    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-configuration-processor</artifactId>
        <optional>true</optional>
    </dependency>
    <!-- Druid Pool -->
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
        <version>${druid.version}</version>
    </dependency>
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <scope>runtime</scope>
    </dependency>
    <!--lombok-->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>${lombok.version}</version>
    </dependency>
    <!--fastjson-->
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>fastjson</artifactId>
        <version>${fastjson.version}</version>
    </dependency>
    <!--mybatispuls-->
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>${mybatis-puls.version}</version>
    </dependency>
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus</artifactId>
        <version>${mybatis-puls.version}</version>
    </dependency>
    <!--InitFreemarker 這個好像是自動生成mybatis文件的 我不知道有沒有用處 -->      <dependency>
        <groupId>org.freemarker</groupId>
        <artifactId>freemarker</artifactId>
    </dependency>
</dependencies>

第二個模塊示例圖：這個作爲被調用方，專業術語叫什麼RM還是TM來着，後面再更新吧

基礎業務層不想多做介紹哈。正常使用自動生成文件，生成就OK了，放入自己的項目裏面。

介紹一下下面的幾個：application.properties,file.conf,registry.conf和druid包下的

1、application.properties

server.port= 6666
spring.application.name=seata-animal
eureka.instance.hostname=localhost
eureka.client.service-url.defaultZone= http://${eureka.instance.hostname}:8888/eureka/
spring.cloud.alibaba.seata.tx-service-group=my_transation  
logging.level.org.springframework.cloud.alibaba.seata.web=debug
logging.level.io.seata=debug


# 驅動配置信息
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.url = jdbc:mysql://127.0.0.1:3306/xx?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
spring.datasource.username = root
spring.datasource.password = root
spring.datasource.driverClassName = com.mysql.cj.jdbc.Driver

#連接池的配置信息
spring.datasource.initialSize=5
spring.datasource.minIdle=5
spring.datasource.maxActive=20
spring.datasource.maxWait=60000
spring.datasource.timeBetweenEvictionRunsMillis=60000
spring.datasource.minEvictableIdleTimeMillis=300000
spring.datasource.validationQuery=SELECT 1 FROM DUAL
spring.datasource.testWhileIdle=true
spring.datasource.testOnBorrow=false
spring.datasource.testOnReturn=false
spring.datasource.poolPreparedStatements=true
spring.datasource.maxPoolPreparedStatementPerConnectionSize=20
spring.datasource.filters=stat,wall,slf4j
spring.datasource.connectionProperties=druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
mybatis-plus.mapper-locations=classpath:mapper/*.xml
mybatis-plus.type-aliases-package=com.gzf.pojo

spring.cloud.alibaba.seata.tx-service-group=my_transation這裏設置的 要和 file.conf裏面的vgroup_mapping.XX對應起來  我這裏是my_transation  那file.conf裏面應該是   vgroup_mapping.my_transation   否則就會報錯。如下：

com.alibaba.fescar.common.exception.FrameworkException: can not connect to fescar-server.

2、file.conf

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_transation = "default"    
  #only support single node
  localRgroup.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
  }
}

需要注意的點：
        1、vgroup_mapping.my_transation = "default"   需要對應配置文件裏面的 spring.cloud.alibaba.seata.tx-service-group=my_transation

2、localRgroup.grouplist = "127.0.0.1:8091" 是對應的 seata-server服務的【seata-server下載】，具體配置下面再講，我先講完代碼。。

3、registry.conf 純複製吧，，

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"
  }
}

4、druid包

一個一個來 DataBasaeConfiguration.java

強調的是引包問題

這裏說明一下,seata是要在數據源處做代理的，具體就看官方介紹吧，上面有鏈接。

@Bean(initMethod = "init", destroyMethod = "close")     //聲明其爲Bean實例
    @Primary  //在同樣的DataSource中，首先使用被標註的DataSource
    public DruidDataSource dataSource() {
        DruidDataSource datasource = new DruidDataSource();

        datasource.setUrl(this.dbUrl);
        datasource.setUsername(username);
        datasource.setPassword(password);
        datasource.setDriverClassName(driverClassName);

        //configuration
        datasource.setInitialSize(initialSize);
        datasource.setMinIdle(minIdle);
        datasource.setMaxActive(maxActive);
        datasource.setMaxWait(maxWait);
        datasource.setTimeBetweenEvictionRunsMillis(timeBetweenEvictionRunsMillis);
        datasource.setMinEvictableIdleTimeMillis(minEvictableIdleTimeMillis);
        datasource.setValidationQuery(validationQuery);
        datasource.setTestWhileIdle(testWhileIdle);
        datasource.setTestOnBorrow(testOnBorrow);
        datasource.setTestOnReturn(testOnReturn);
        datasource.setPoolPreparedStatements(poolPreparedStatements);
        datasource.setMaxPoolPreparedStatementPerConnectionSize(maxPoolPreparedStatementPerConnectionSize);
        try {
            datasource.setFilters(filters);
        } catch (SQLException e) {
            log.info("druid configuration initialization filter",e);
        }
        datasource.setConnectionProperties(connectionProperties);

        return datasource;
    }


//代理
 @Bean
    public DataSourceProxy dataSourceProxy(DruidDataSource druidDataSource) {
        //com.alibaba.fescar.rm.datasource.DataSourceProxy;   <artifactId>fescar-rm-datasource</artifactId>
        return new DataSourceProxy(druidDataSource);
    }


     /**這個攔截器的流程是，feign遠程調用開始的時候 會在RequestHeaderInterceptor中攔截XID，
     * 然後再SeataXidFilter裏面獲取XID，保證事務能夠傳播到遠程服務，保證事務成功/回滾
     * @Description:
     * @Author:gaozifeng
     * @Date 2019/7/26 18:05
     **/
    @Bean
    public SeataXidFilter fescarXidFilter() {
        return new SeataXidFilter();
    }

   /**捕捉全局GlobalTransactionScanner
     * 和file中vgroup_mapping.my_transation 後綴保持一致  否則出現連接不上或者 註冊RM 失敗.
     * 且和配置文件中的spring.cloud.alibaba.seata.tx-service-group 保持一致
     * @param :
     * @return : io.seata.spring.annotation.GlobalTransactionScanner
     * @author : gaozifeng
     * @date : 2019/7/29 20:45
     */
    @Bean
    public GlobalTransactionScanner globalTransactionScanner() {
        return new GlobalTransactionScanner("seata-animal", "my_transation");
    }

    @Bean(name = "mysqlUserTransactionManager")
    public DataSourceTransactionManager initTransactionManager(@Autowired DataSourceProxy dataSource) {
        try {
            return new DataSourceTransactionManager(dataSource);
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    @Bean(name = "mysqlUserSqlSessionFactory")
    public SqlSessionFactory initSqlSessionFactory(@Autowired DataSourceProxy dataSource
            , @Autowired PaginationInterceptor paginationInterceptor)
            throws Exception {

        MybatisSqlSessionFactoryBean mybatisSqlSessionFactoryBean = new MybatisSqlSessionFactoryBean();
        mybatisSqlSessionFactoryBean.setDataSource(dataSource);

        MybatisConfiguration mybatisConfiguration = new MybatisConfiguration();
        mybatisConfiguration.setLogImpl(org.apache.ibatis.logging.stdout.StdOutImpl.class);
        mybatisConfiguration.setMapUnderscoreToCamelCase(true);
        mybatisSqlSessionFactoryBean.setConfiguration(mybatisConfiguration);

        mybatisSqlSessionFactoryBean.setPlugins(new Interceptor[]{paginationInterceptor});

        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        mybatisSqlSessionFactoryBean.setTypeAliasesPackage("com.gzf.pojo");
        //開啓mapper掃描
        mybatisSqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath:mapper/*.xml"));
        mybatisSqlSessionFactoryBean.setVfs(SpringBootVFS.class);
        return mybatisSqlSessionFactoryBean.getObject();
    }

    /**
     * mybatis-plus分頁插件<br>
     * 文檔：http://mp.baomidou.com<br>
     */
    @Bean
    public PaginationInterceptor paginationInterceptor() {
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        return paginationInterceptor;
    }

RequestHeaderInterceptor.java 準確來說，這個是要用在seata-animal上面的，因爲seata-user會使用feign調用animal項目，可能理解有誤哈

/**
 * Feign攔截器，把RootContext中的XID（XID用於標識一個局部事務屬於哪個全局事務，需要在調用鏈路的上下文中傳遞）傳遞到上層調用鏈路
 * 
 * @author gzf
 * @time 2019.07.31
 */
@Component
public class RequestHeaderInterceptor implements RequestInterceptor {

	@Override
	public void apply(RequestTemplate template) {
		String xid = RootContext.getXID();
		if (StringUtils.isNotBlank(xid)) {
			template.header(SeataConstant.XID_HEADER, xid);
		}
	}

}

SeataConstant.java 固定

public class SeataConstant {
	/** seata Xid header */
	public static final String XID_HEADER = "Xid_Header";
}

SeataXidFilter.java  不難理解

/**
 * Http Rest請求攔截器，用於把當前上下文中獲取到的XID放到RootContext
 * @author gzf
 * @time 2019.07.31
 */
public class SeataXidFilter extends OncePerRequestFilter {
	protected Logger logger = LoggerFactory.getLogger(SeataXidFilter.class);

	@Override
	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
			throws ServletException, IOException {
		String xid = RootContext.getXID();
		String restXid = request.getHeader(SeataConstant.XID_HEADER);
		boolean bind = false;
		if (StringUtils.isBlank(xid) && StringUtils.isNotBlank(restXid)) {
			RootContext.bind(restXid);
			bind = true;
			if (logger.isDebugEnabled()) {
				logger.debug("bind[" + restXid + "] to RootContext");
			}
		}
		try {
			filterChain.doFilter(request, response);
		} finally {
			if (bind) {
				String unbindXid = RootContext.unbind();
				if (logger.isDebugEnabled()) {
					logger.debug("unbind[" + unbindXid + "] from RootContext");
				}
				if (!restXid.equalsIgnoreCase(unbindXid)) {
					logger.warn("xid in change during http rest from " + restXid + " to " + unbindXid);
					if (unbindXid != null) {
						RootContext.bind(unbindXid);
						logger.warn("bind [" + unbindXid + "] back to RootContext");
					}
				}
			}
		}

	}

}

AnimalServiceImpl.java 作爲服務調用方， 這裏最好是記錄一個返回值，否則的話，操作過程中如果出現問題，就會導致服務之間事務失敗。

被調用方介紹到這裏，下面看一下調用方。

seata-user 如上除了ServiceImpl不同其他除了類名都相同。

這裏只新增了一個@GlobalTransactional，識別全局事務id，此ID會由seata來生成，規則是ip+port+transactionid

首先說一下，在本項目執行完userMapper.save方法之後，會在數據庫生成對應的undo_log，日誌。如果接下來項目出錯，就會用日誌回滾了。

代碼介紹完了，剩下來就介紹一下seata-server端了。

這個端其實不難，

我做了一個文件的更改 registry文件

然後就啓動 bin 下面的文件吧，

貼一下成功案例哈，

undo_log

事務成功：業務庫保留數據，undo_log記錄會在異步開啓線程執行刪除；

事務失敗：業務庫刪除數據，undo_log保留記錄；

項目也開源了

https://gitee.com/wqnmlgbaw/seata-gzf 歡迎下載

轉載請標誌出處哈，

seata分佈式事務--看這一篇就夠了~

seata分佈式事務--看這一篇就夠了~

碼雲中怎麼刪除項目中某一模塊

Java面試題，List集合中根據對象的某一屬性排序

solr7.2.1使用增量更新

Mybatis.xml文件設置自動提醒

Mac下配置sublime實現LaTeX

https://yachay.unat.edu.pe/blog/index.php?comment_area=format_blog&comment_component=blog&comment_co

linux以太網驅動總結