Seata源碼—2.seata-samples項目介紹
大綱
1.seata-samples的配置文件和啟動類
2.seata-samples業(yè)務(wù)服務(wù)啟動時的核心工作
3.seata-samples庫存服務(wù)的連接池配置
4.Seata對數(shù)據(jù)庫連接池代理配置的分析
5.Dubbo RPC通信過程中傳遞全局事務(wù)XID
6.Seata跟Dubbo整合的Filter(基于SPI機制)
7.seata-samples的AT事務(wù)例子原理流程
8.Seata核心配置文件file.conf的內(nèi)容介紹
1.seata-samples的配置文件和啟動類
(1)seata-samples的測試步驟
(2)seata-samples用戶服務(wù)的配置和啟動類
(3)seata-samples庫存服務(wù)的配置和啟動類
(4)seata-samples訂單服務(wù)的配置和啟動類
(5)seata-samples業(yè)務(wù)服務(wù)的配置和啟動類
示例倉庫：
https://github.com/seata/seata-samples
示例代碼的模塊ID：seata-samples-dubbo
(1)seata-samples的測試步驟
步驟一：啟動DubboAccountServiceStarter
步驟二：啟動DubboStorageServiceStarter
步驟三：啟動DubboOrderServiceStarter
步驟四：運行DubboBusinessTester
(2)seata-samples用戶服務(wù)的配置和啟動類
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文件里的配置加載進來 -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations" value="classpath:jdbc.properties"/>
</bean>
<!-- 將配置文件里的值注入到庫存服務(wù)的數(shù)據(jù)庫連接池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>
<!-- 創(chuàng)建數(shù)據(jù)庫連接池代理，通過DataSourceProxy代理accountDataSourceProxy數(shù)據(jù)庫連接池 -->
<bean id="accountDataSourceProxy" class="io.seata.rm.datasource.DataSourceProxy">
<constructor-arg ref="accountDataSource"/>
</bean>
<!-- 將數(shù)據(jù)庫連接池代理accountDataSourceProxy注入到JdbcTemplate數(shù)據(jù)庫操作組件中-->
<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"/>
<!-- 將JdbcTemplate數(shù)據(jù)庫操作組件注入到AccountServiceImpl中 -->
<bean id="service" class="io.seata.samples.dubbo.service.impl.AccountServiceImpl">
<property name="jdbcTemplate" ref="jdbcTemplate"/>
</bean>
<!-- 全局事務(wù)注解掃描組件 -->
<bean class="io.seata.spring.annotation.GlobalTransactionScanner">
<constructor-arg value="dubbo-demo-account-service"/>
<constructor-arg value="my_test_tx_group"/>
</bean>
</beans>
啟動類：
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庫存服務(wù)的配置和啟動類
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文件里的配置加載進來 -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations" value="classpath:jdbc.properties"/>
</bean>
<!-- 將配置文件里的值注入到庫存服務(wù)的數(shù)據(jù)庫連接池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>
<!-- 創(chuàng)建數(shù)據(jù)庫連接池代理，通過DataSourceProxy代理stockDataSource數(shù)據(jù)庫連接池 -->
<bean id="stockDataSourceProxy" class="io.seata.rm.datasource.DataSourceProxy">
<constructor-arg ref="stockDataSource"/>
</bean>
<!-- 將數(shù)據(jù)庫連接池代理stockDataSourceProxy注入到JdbcTemplate數(shù)據(jù)庫操作組件中-->
<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"/>
<!-- 將JdbcTemplate數(shù)據(jù)庫操作組件注入到StockServiceImpl中 -->
<bean id="service" class="io.seata.samples.dubbo.service.impl.StockServiceImpl">
<property name="jdbcTemplate" ref="jdbcTemplate"/>
</bean>
<!-- 全局事務(wù)注解掃描組件 -->
<bean class="io.seata.spring.annotation.GlobalTransactionScanner">
<constructor-arg value="dubbo-demo-stock-service"/>
<constructor-arg value="my_test_tx_group"/>
</bean>
</beans>
啟動類：
//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訂單服務(wù)的配置和啟動類
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文件里的配置加載進來 -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations" value="classpath:jdbc.properties"/>
</bean>
<!-- 將配置文件里的值注入到庫存服務(wù)的數(shù)據(jù)庫連接池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>
<!-- 創(chuàng)建數(shù)據(jù)庫連接池代理，通過DataSourceProxy代理stockDataSource數(shù)據(jù)庫連接池 -->
<bean id="orderDataSourceProxy" class="io.seata.rm.datasource.DataSourceProxy">
<constructor-arg ref="orderDataSource"/>
</bean>
<!-- 將數(shù)據(jù)庫連接池代理orderDataSourceProxy注入到JdbcTemplate數(shù)據(jù)庫操作組件中-->
<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"/>
<!-- 將JdbcTemplate數(shù)據(jù)庫操作組件注入到OrderServiceImpl中 -->
<bean id="service" class="io.seata.samples.dubbo.service.impl.OrderServiceImpl">
<property name="jdbcTemplate" ref="jdbcTemplate"/>
<property name="accountService" ref="accountService"/>
</bean>
<!-- 全局事務(wù)注解掃描組件 -->
<bean class="io.seata.spring.annotation.GlobalTransactionScanner">
<constructor-arg value="dubbo-demo-order-service"/>
<constructor-arg value="my_test_tx_group"/>
</bean>
</beans>
啟動類：
//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業(yè)務(wù)服務(wù)的配置和啟動類
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>
<!-- 全局事務(wù)注解掃描組件 -->
<bean class="io.seata.spring.annotation.GlobalTransactionScanner">
<constructor-arg value="dubbo-demo-app"/>
<constructor-arg value="my_test_tx_group"/>
</bean>
</beans>
啟動類：
//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"}
);
//模擬調(diào)用下單接口
final BusinessService business = (BusinessService)context.getBean("business");
business.purchase("U100001", "C00321", 2);
}
}
2.seata-samples業(yè)務(wù)服務(wù)啟動時的核心工作
BusinessService業(yè)務(wù)服務(wù)啟動時，會創(chuàng)建兩個服務(wù)接口的動態(tài)代理。一個是OrderService訂單服務(wù)接口的Dubbo動態(tài)代理，另一個是StockService庫存服務(wù)接口的Dubbo動態(tài)代理。BusinessService業(yè)務(wù)服務(wù)的下單接口會添加@GlobalTransaction注解，通過@GlobalTransaction注解開啟一個分布式事務(wù)，Seata的內(nèi)核組件GlobalTransactionScanner就會掃描到這個注解。
//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"}
);
//模擬調(diào)用下單接口
final BusinessService business = (BusinessService)context.getBean("business");
business.purchase("U100001", "C00321", 2);
}
}
public class BusinessServiceImpl implements BusinessService {
private static final Logger LOGGER = LoggerFactory.getLogger(BusinessService.class);
private StockService stockService;
private OrderService orderService;
private Random random = new Random();
@Override
@GlobalTransactional(timeoutMills = 300000, name = "dubbo-demo-tx")//分布式事務(wù)如果5分鐘還沒跑完，就是超時
public void purchase(String userId, String commodityCode, int orderCount) {
LOGGER.info("purchase begin ... xid: " + RootContext.getXID());
stockService.deduct(commodityCode, orderCount);
orderService.create(userId, commodityCode, orderCount);
if (random.nextBoolean()) {
throw new RuntimeException("random exception mock!");
}
}
//Sets stock service.
public void setStockService(StockService stockService) {
this.stockService = stockService;
}
//Sets order service.
public void setOrderService(OrderService orderService) {
this.orderService = orderService;
}
}
3.seata-samples庫存服務(wù)的連接池配置
首先會把jdbc.properties文件里的配置加載進來，然后將配置配置的值注入到庫存服務(wù)的數(shù)據(jù)庫連接池，接著通過Seata的DataSourceProxy對數(shù)據(jù)庫連接池進行代理。
一.啟動類
//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();
}
}
二.dubbo-stock-service.xml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文件里的配置加載進來 -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations" value="classpath:jdbc.properties"/>
</bean>
<!-- 將配置文件里的值注入到庫存服務(wù)的數(shù)據(jù)庫連接池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>
<!-- 創(chuàng)建數(shù)據(jù)庫連接池代理，通過DataSourceProxy代理stockDataSource數(shù)據(jù)庫連接池 -->
<bean id="stockDataSourceProxy" class="io.seata.rm.datasource.DataSourceProxy">
<constructor-arg ref="stockDataSource"/>
</bean>
<!-- 將數(shù)據(jù)庫連接池代理stockDataSourceProxy注入到JdbcTemplate數(shù)據(jù)庫操作組件中-->
<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"/>
<!-- 將JdbcTemplate數(shù)據(jù)庫操作組件注入到StockServiceImpl中 -->
<bean id="service" class="io.seata.samples.dubbo.service.impl.StockServiceImpl">
<property name="jdbcTemplate" ref="jdbcTemplate"/>
</bean>
<!-- 全局事務(wù)注解掃描組件 -->
<bean class="io.seata.spring.annotation.GlobalTransactionScanner">
<constructor-arg value="dubbo-demo-stock-service"/>
<constructor-arg value="my_test_tx_group"/>
</bean>
</beans>
三.jdbc.properties文件文件
jdbc.account.url=jdbc:mysql://localhost:3306/seata jdbc.account.username=root jdbc.account.password=123456 jdbc.account.driver=com.mysql.jdbc.Driver # stock db config jdbc.stock.url=jdbc:mysql://localhost:3306/seata jdbc.stock.username=root jdbc.stock.password=123456 jdbc.stock.driver=com.mysql.jdbc.Driver # order db config jdbc.order.url=jdbc:mysql://localhost:3306/seata jdbc.order.username=root jdbc.order.password=123456 jdbc.order.driver=com.mysql.jdbc.Driver
4.Seata對數(shù)據(jù)庫連接池代理配置的分析
數(shù)據(jù)庫連接池代理DataSourceProxy，會注入到JdbcTemplate數(shù)據(jù)庫操作組件中。這樣庫存或者訂單服務(wù)就可以通過Spring數(shù)據(jù)庫操作組件JdbcTemplate，向Seata數(shù)據(jù)庫連接池代理DataSourceProxy獲取一個數(shù)據(jù)庫連接。然后通過數(shù)據(jù)庫連接，把SQL請求發(fā)送給MySQL進行處理。
5.Dubbo RPC通信過程中傳遞全局事務(wù)XID
BusinessService對StockService進行RPC調(diào)用時，會傳遞全局事務(wù)XID。StockService便可以根據(jù)RootContext.getXID()獲取到全局事務(wù)XID。
public class BusinessServiceImpl implements BusinessService {
private static final Logger LOGGER = LoggerFactory.getLogger(BusinessService.class);
private StockService stockService;
private OrderService orderService;
private Random random = new Random();
@Override
@GlobalTransactional(timeoutMills = 300000, name = "dubbo-demo-tx")//分布式事務(wù)如果5分鐘還沒跑完，就是超時
public void purchase(String userId, String commodityCode, int orderCount) {
LOGGER.info("purchase begin ... xid: " + RootContext.getXID());
stockService.deduct(commodityCode, orderCount);
orderService.create(userId, commodityCode, orderCount);
if (random.nextBoolean()) {
throw new RuntimeException("random exception mock!");
}
}
...
}
public class StockServiceImpl implements StockService {
private static final Logger LOGGER = LoggerFactory.getLogger(StockService.class);
private JdbcTemplate jdbcTemplate;
@Override
public void deduct(String commodityCode, int count) {
LOGGER.info("Stock Service Begin ... xid: " + RootContext.getXID());
LOGGER.info("Deducting inventory SQL: update stock_tbl set count = count - {} where commodity_code = {}", count, commodityCode);
jdbcTemplate.update("update stock_tbl set count = count - ? where commodity_code = ?", new Object[] {count, commodityCode});
LOGGER.info("Stock Service End ... ");
}
...
}
6.Seata跟Dubbo整合的Filter(基于SPI機制)
Seata與Dubbo整合的Filter過濾器ApacheDubboTransactionPropagationFilter會將向SeataServer注冊的全局事務(wù)xid，設(shè)置到RootContext中。
7.seata-samples的AT事務(wù)例子原理流程
8.Seata核心配置文件file.conf的內(nèi)容介紹
# Seata網(wǎng)絡(luò)通信相關(guān)的配置
transport {
# 網(wǎng)絡(luò)通信的類型是TCP
type = "TCP"
# 網(wǎng)絡(luò)服務(wù)端使用NIO模式
server = "NIO"
# 是否開啟心跳
heartbeat = true
# 是否允許Seata的客戶端批量發(fā)送請求
enableClientBatchSendRequest = true
# 使用Netty進行網(wǎng)絡(luò)通信時的線程配置
threadFactory {
bossThreadPrefix = "NettyBoss"
workerThreadPrefix = "NettyServerNIOWorker"
serverExecutorThread-prefix = "NettyServerBizHandler"
shareBossWorker = false
clientSelectorThreadPrefix = "NettyClientSelector"
clientSelectorThreadSize = 1
clientWorkerThreadPrefix = "NettyClientWorkerThread"
# 用來監(jiān)聽和建立網(wǎng)絡(luò)連接的Boss線程的數(shù)量
bossThreadSize = 1
# 默認的Worker線程數(shù)量是8
workerThreadSize = "default"
}
shutdown {
# 銷毀服務(wù)端的時候的等待時間是多少秒
wait = 3
}
# 序列化類型是Seata
serialization = "seata"
# 是否開啟壓縮
compressor = "none"
}
# Seata服務(wù)端相關(guān)的配置
service {
# 分布式事務(wù)的分組
vgroupMapping.my_test_tx_group = "default"
# only support when registry.type=file, please don't set multiple addresses
default.grouplist = "127.0.0.1:8091"
# 是否開啟降級
enableDegrade = false
# 是否禁用全局事務(wù)
disableGlobalTransaction = false
}
# Seata客戶端相關(guān)的配置
client {
# 數(shù)據(jù)源管理組件的配置
rm {
# 異步提交緩沖區(qū)的大小
asyncCommitBufferLimit = 10000
# 鎖相關(guān)的配置：重試間隔、重試次數(shù)、回滾沖突處理
lock {
retryInterval = 10
retryTimes = 30
retryPolicyBranchRollbackOnConflict = true
}
reportRetryCount = 5
tableMetaCheckEnable = false
reportSuccessEnable = false
}
# 事務(wù)管理組件的配置
tm {
commitRetryCount = 5
rollbackRetryCount = 5
}
# 回滾日志的配置
undo {
dataValidation = true
logSerialization = "jackson"
logTable = "undo_log"
}
# log日志的配置
log {
exceptionRate = 100
}
}
后端技術(shù)棧的基礎(chǔ)修養(yǎng) 文章被收錄于專欄
詳細介紹后端技術(shù)棧的基礎(chǔ)內(nèi)容，包括但不限于：MySQL原理和優(yōu)化、Redis原理和應(yīng)用、JVM和G1原理和優(yōu)化、RocketMQ原理應(yīng)用及源碼、Kafka原理應(yīng)用及源碼、ElasticSearch原理應(yīng)用及源碼、JUC源碼、Netty源碼、zk源碼、Dubbo源碼、Spring源碼、Spring Boot源碼、SCA源碼、分布式鎖源碼、分布式事務(wù)、分庫分表和TiDB、大型商品系統(tǒng)、大型訂單系統(tǒng)等
