Seata源码—2.seata-samples项目介绍

大纲

1.seata-samples的配置文件和启动类

2.seata-samples业务服务启动时的核心工作

3.seata-samples库存服务的连接池配置

4.Seata对数据库连接池代理配置的分析

5.Dubbo RPC通信过程中传递全局事务XID

6.Seata跟Dubbo整合的Filter(基于SPI机制)

7.seata-samples的AT事务例子原理流程

8.Seata核心配置文件file.conf的内容介绍

1.seata-samples的配置文件和启动类

(1)seata-samples的测试步骤

(2)seata-samples用户服务的配置和启动类

(3)seata-samples库存服务的配置和启动类

(4)seata-samples订单服务的配置和启动类

(5)seata-samples业务服务的配置和启动类

示例仓库：

https://github.com/seata/seata-samples

示例代码的模块ID：seata-samples-dubbo

(1)seata-samples的测试步骤

步骤一：启动DubboAccountServiceStarter

步骤二：启动DubboStorageServiceStarter

步骤三：启动DubboOrderServiceStarter

步骤四：运行DubboBusinessTester

(2)seata-samples用户服务的配置和启动类

dubbo-account-service.xml配置文件：

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans"      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"      xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"      xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">          <!-- 把jdbc.properties文件里的配置加载进来 -->     <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">         <property name="locations" value="classpath:jdbc.properties"/>     </bean>          <!-- 将配置文件里的值注入到库存服务的数据库连接池accountDataSource中 -->     <bean name="accountDataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">         <property name="url" value="${jdbc.account.url}"/>         <property name="username" value="${jdbc.account.username}"/>         <property name="password" value="${jdbc.account.password}"/>         <property name="driverClassName" value="${jdbc.account.driver}"/>         <property name="initialSize" value="0"/>         <property name="maxActive" value="180"/>         <property name="minIdle" value="0"/>         <property name="maxWait" value="60000"/>         <property name="validationQuery" value="Select 'x' from DUAL"/>         <property name="testOnBorrow" value="false"/>         <property name="testOnReturn" value="false"/>         <property name="testWhileIdle" value="true"/>         <property name="timeBetweenEvictionRunsMillis" value="60000"/>         <property name="minEvictableIdleTimeMillis" value="25200000"/>         <property name="removeAbandoned" value="true"/>         <property name="removeAbandonedTimeout" value="1800"/>         <property name="logAbandoned" value="true"/>         <property name="filters" value="mergeStat"/>     </bean>          <!-- 创建数据库连接池代理，通过DataSourceProxy代理accountDataSourceProxy数据库连接池 -->     <bean id="accountDataSourceProxy" class="io.seata.rm.datasource.DataSourceProxy">         <constructor-arg ref="accountDataSource"/>     </bean>          <!-- 将数据库连接池代理accountDataSourceProxy注入到JdbcTemplate数据库操作组件中-->     <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">         <property name="dataSource" ref="accountDataSourceProxy"/>     </bean>      <dubbo:application name="dubbo-demo-account-service">         <dubbo:parameter key="qos.enable" value="false"/>     </dubbo:application>     <dubbo:registry address="zookeeper://localhost:2181" />     <dubbo:protocol name="dubbo" port="20881"/>     <dubbo:service interface="io.seata.samples.dubbo.service.AccountService" ref="service" timeout="10000"/>          <!-- 将JdbcTemplate数据库操作组件注入到AccountServiceImpl中 -->     <bean id="service" class="io.seata.samples.dubbo.service.impl.AccountServiceImpl">         <property name="jdbcTemplate" ref="jdbcTemplate"/>     </bean>          <!-- 全局事务注解扫描组件 -->     <bean class="io.seata.spring.annotation.GlobalTransactionScanner">         <constructor-arg value="dubbo-demo-account-service"/>         <constructor-arg value="my_test_tx_group"/>     </bean> </beans>

启动类：

public class DubboAccountServiceStarter {     //Account service is ready. A buyer register an account: U100001 on my e-commerce platform     public static void main(String[] args) {         ClassPathXmlApplicationContext accountContext = new ClassPathXmlApplicationContext(             new String[] {"spring/dubbo-account-service.xml"}         );         accountContext.getBean("service");         JdbcTemplate accountJdbcTemplate = (JdbcTemplate)accountContext.getBean("jdbcTemplate");         accountJdbcTemplate.update("delete from account_tbl where user_id = 'U100001'");         accountJdbcTemplate.update("insert into account_tbl(user_id, money) values ('U100001', 999)");         new ApplicationKeeper(accountContext).keep();     } }  //The type Application keeper. public class ApplicationKeeper {     private static final Logger LOGGER = LoggerFactory.getLogger(ApplicationKeeper.class);     private final ReentrantLock LOCK = new ReentrantLock();     private final Condition STOP = LOCK.newCondition();      //Instantiates a new Application keeper.     public ApplicationKeeper(AbstractApplicationContext applicationContext) {         addShutdownHook(applicationContext);     }          private void addShutdownHook(final AbstractApplicationContext applicationContext) {         Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {             @Override             public void run() {                 try {                     applicationContext.close();                     LOGGER.info("ApplicationContext " + applicationContext + " is closed.");                 } catch (Exception e) {                     LOGGER.error("Failed to close ApplicationContext", e);                 }                  LOCK.lock();                 try {                     STOP.signal();                 } finally {                     LOCK.unlock();                 }             }         }));     }          public void keep() {         LOCK.lock();         try {             LOGGER.info("Application is keep running ... ");             STOP.await();         } catch (InterruptedException e) {             LOGGER.error("ApplicationKeeper.keep() is interrupted by InterruptedException!", e);         } finally {             LOCK.unlock();         }     } }

(3)seata-samples库存服务的配置和启动类

dubbo-stock-service.xml配置文件：

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans"      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"      xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"      xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">          <!-- 把jdbc.properties文件里的配置加载进来 -->     <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">         <property name="locations" value="classpath:jdbc.properties"/>     </bean>          <!-- 将配置文件里的值注入到库存服务的数据库连接池stockDataSource中 -->     <bean name="stockDataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">         <property name="url" value="${jdbc.stock.url}"/>         <property name="username" value="${jdbc.stock.username}"/>         <property name="password" value="${jdbc.stock.password}"/>         <property name="driverClassName" value="${jdbc.stock.driver}"/>         <property name="initialSize" value="0"/>         <property name="maxActive" value="180"/>         <property name="minIdle" value="0"/>         <property name="maxWait" value="60000"/>         <property name="validationQuery" value="Select 'x' from DUAL"/>         <property name="testOnBorrow" value="false"/>         <property name="testOnReturn" value="false"/>         <property name="testWhileIdle" value="true"/>         <property name="timeBetweenEvictionRunsMillis" value="60000"/>         <property name="minEvictableIdleTimeMillis" value="25200000"/>         <property name="removeAbandoned" value="true"/>         <property name="removeAbandonedTimeout" value="1800"/>         <property name="logAbandoned" value="true"/>         <property name="filters" value="mergeStat"/>     </bean>          <!-- 创建数据库连接池代理，通过DataSourceProxy代理stockDataSource数据库连接池 -->     <bean id="stockDataSourceProxy" class="io.seata.rm.datasource.DataSourceProxy">         <constructor-arg ref="stockDataSource"/>     </bean>      <!-- 将数据库连接池代理stockDataSourceProxy注入到JdbcTemplate数据库操作组件中-->     <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">         <property name="dataSource" ref="stockDataSourceProxy"/>     </bean>      <dubbo:application name="dubbo-demo-stock-service">         <dubbo:parameter key="qos.enable" value="false"/>     </dubbo:application>     <dubbo:registry address="zookeeper://localhost:2181" />     <dubbo:protocol name="dubbo" port="20882"/>     <dubbo:service interface="io.seata.samples.dubbo.service.StockService" ref="service" timeout="10000"/>          <!-- 将JdbcTemplate数据库操作组件注入到StockServiceImpl中 -->     <bean id="service" class="io.seata.samples.dubbo.service.impl.StockServiceImpl">         <property name="jdbcTemplate" ref="jdbcTemplate"/>     </bean>          <!-- 全局事务注解扫描组件 -->     <bean class="io.seata.spring.annotation.GlobalTransactionScanner">         <constructor-arg value="dubbo-demo-stock-service"/>         <constructor-arg value="my_test_tx_group"/>     </bean> </beans>

启动类：

//The type Dubbo stock service starter. public class DubboStockServiceStarter {     //Stock service is ready. A seller add 100 stock to a sku: C00321     public static void main(String[] args) {         ClassPathXmlApplicationContext stockContext = new ClassPathXmlApplicationContext(             new String[] {"spring/dubbo-stock-service.xml"}         );         stockContext.getBean("service");         JdbcTemplate stockJdbcTemplate = (JdbcTemplate)stockContext.getBean("jdbcTemplate");         stockJdbcTemplate.update("delete from stock_tbl where commodity_code = 'C00321'");         stockJdbcTemplate.update("insert into stock_tbl(commodity_code, count) values ('C00321', 100)");         new ApplicationKeeper(stockContext).keep();     } }

(4)seata-samples订单服务的配置和启动类

dubbo-order-service.xml配置文件：

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans"      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"      xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"      xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">          <!-- 把jdbc.properties文件里的配置加载进来 -->     <bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">         <property name="locations" value="classpath:jdbc.properties"/>     </bean>          <!-- 将配置文件里的值注入到库存服务的数据库连接池orderDataSource中 -->     <bean name="orderDataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">         <property name="url" value="${jdbc.order.url}"/>         <property name="username" value="${jdbc.order.username}"/>         <property name="password" value="${jdbc.order.password}"/>         <property name="driverClassName" value="${jdbc.order.driver}"/>         <property name="initialSize" value="0"/>         <property name="maxActive" value="180"/>         <property name="minIdle" value="0"/>         <property name="maxWait" value="60000"/>         <property name="validationQuery" value="Select 'x' from DUAL"/>         <property name="testOnBorrow" value="false"/>         <property name="testOnReturn" value="false"/>         <property name="testWhileIdle" value="true"/>         <property name="timeBetweenEvictionRunsMillis" value="60000"/>         <property name="minEvictableIdleTimeMillis" value="25200000"/>         <property name="removeAbandoned" value="true"/>         <property name="removeAbandonedTimeout" value="1800"/>         <property name="logAbandoned" value="true"/>         <property name="filters" value="mergeStat"/>     </bean>          <!-- 创建数据库连接池代理，通过DataSourceProxy代理stockDataSource数据库连接池 -->     <bean id="orderDataSourceProxy" class="io.seata.rm.datasource.DataSourceProxy">         <constructor-arg ref="orderDataSource"/>     </bean>          <!-- 将数据库连接池代理orderDataSourceProxy注入到JdbcTemplate数据库操作组件中-->     <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">         <property name="dataSource" ref="orderDataSourceProxy"/>     </bean>      <dubbo:application name="dubbo-demo-order-service">         <dubbo:parameter key="qos.enable" value="false"/>     </dubbo:application>     <dubbo:registry address="zookeeper://localhost:2181" />     <dubbo:protocol name="dubbo" port="20883"/>     <dubbo:service interface="io.seata.samples.dubbo.service.OrderService" ref="service" timeout="10000"/>     <dubbo:reference id="accountService" check="false" interface="io.seata.samples.dubbo.service.AccountService"/>          <!-- 将JdbcTemplate数据库操作组件注入到OrderServiceImpl中 -->     <bean id="service" class="io.seata.samples.dubbo.service.impl.OrderServiceImpl">         <property name="jdbcTemplate" ref="jdbcTemplate"/>         <property name="accountService" ref="accountService"/>     </bean>          <!-- 全局事务注解扫描组件 -->     <bean class="io.seata.spring.annotation.GlobalTransactionScanner">         <constructor-arg value="dubbo-demo-order-service"/>         <constructor-arg value="my_test_tx_group"/>     </bean> </beans>

启动类：

//The type Dubbo order service starter. public class DubboOrderServiceStarter {     //The entry point of application.     public static void main(String[] args) {         //Order service is ready . Waiting for buyers to order         ClassPathXmlApplicationContext orderContext = new ClassPathXmlApplicationContext(             new String[] {"spring/dubbo-order-service.xml"}         );         orderContext.getBean("service");         new ApplicationKeeper(orderContext).keep();     } }

(5)seata-samples业务服务的配置和启动类

dubbo-business.xml配置文件：

<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans"      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"      xmlns:dubbo="http://dubbo.apache.org/schema/dubbo"      xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://dubbo.apache.org/schema/dubbo http://dubbo.apache.org/schema/dubbo/dubbo.xsd">      <dubbo:application name="dubbo-demo-app">         <dubbo:parameter key="qos.enable" value="false"/>         <dubbo:parameter key="qos.accept.foreign.ip" value="false"/>         <dubbo:parameter key="qos.port" value="33333"/>     </dubbo:application>     <dubbo:registry address="zookeeper://localhost:2181" />     <dubbo:reference id="orderService" check="false" interface="io.seata.samples.dubbo.service.OrderService"/>     <dubbo:reference id="stockService" check="false" interface="io.seata.samples.dubbo.service.StockService"/>      <bean id="business" class="io.seata.samples.dubbo.service.impl.BusinessServiceImpl">         <property name="orderService" ref="orderService"/>         <property name="stockService" ref="stockService"/>     </bean>          <!-- 全局事务注解扫描组件 -->     <bean class="io.seata.spring.annotation.GlobalTransactionScanner">         <constructor-arg value="dubbo-demo-app"/>         <constructor-arg value="my_test_tx_group"/>     </bean> </beans>

启动类：

//The type Dubbo business tester. public class DubboBusinessTester {     //The entry point of application.     public static void main(String[] args) {         //The whole e-commerce platform is ready, The buyer(U100001) create an order on the sku(C00321) , the count is 2         ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext(             new String[] {"spring/dubbo-business.xml"}         );         //模拟调用下单接口         final BusinessService business = (BusinessService)context.getBean("business");         business.purchase("U100001", "C00321", 2);     } }

2.seata-samples业务服务启动时的核心工作

BusinessService业务服务启动时，会创建两个服务接口的动态代理。一个是OrderService订单服务接口的Dubbo动态代理，另一个是StockService库存服务接口的Dubbo动态代理。BusinessService业务服务的下单接口会添加@GlobalTransaction注解，通过@GlobalTransaction注解开启一个分布式事务，Seata的内核组件GlobalTransactionScanner就会扫描到这个注解。