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">
<bean >
<property name="locations" value="classpath:jdbc.properties"/>
</bean>
<bean name="accountDataSource"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>
<bean id="accountDataSourceProxy" >
<constructor-arg ref="accountDataSource"/>
</bean>
<bean id="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"/>
<bean id="service" >
<property name="jdbcTemplate" ref="jdbcTemplate"/>
</bean>
<bean >
<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">
<bean >
<property name="locations" value="classpath:jdbc.properties"/>
</bean>
<bean name="stockDataSource"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>
<bean id="stockDataSourceProxy" >
<constructor-arg ref="stockDataSource"/>
</bean>
<bean id="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"/>
<bean id="service" >
<property name="jdbcTemplate" ref="jdbcTemplate"/>
</bean>
<bean >
<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">
<bean >
<property name="locations" value="classpath:jdbc.properties"/>
</bean>
<bean name="accountDataSource"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>
<bean id="accountDataSourceProxy" >
<constructor-arg ref="accountDataSource"/>
</bean>
<bean id="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"/>
<bean id="service" >
<property name="jdbcTemplate" ref="jdbcTemplate"/>
</bean>
<bean >
<constructor-arg value="dubbo-demo-account-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" >
<property name="orderService" ref="orderService"/>
<property name="stockService" ref="stockService"/>
</bean>
<bean >
<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。
//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);
}
}
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")//分布式事务如果5分钟还没跑完，就是超时
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库存服务的连接池配置
首先会把jdbc.properties文件里的配置加载进来，然后将配置配置的值注入到库存服务的数据库连接池，接着通过Seata的DataSourceProxy对数据库连接池进行代理。
一.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();
}
}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">
<bean >
<property name="locations" value="classpath:jdbc.properties"/>
</bean>
<bean name="accountDataSource"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>
<bean id="accountDataSourceProxy" >
<constructor-arg ref="accountDataSource"/>
</bean>
<bean id="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"/>
<bean id="service" >
<property name="jdbcTemplate" ref="jdbcTemplate"/>
</bean>
<bean >
<constructor-arg value="dubbo-demo-account-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对数据库连接池代理配置的分析
数据库连接池代理DataSourceProxy，会注入到JdbcTemplate数据库操作组件中。这样库存或者订单服务就可以通过Spring数据库操作组件JdbcTemplate，向Seata数据库连接池代理DataSourceProxy获取一个数据库连接。然后通过数据库连接，把SQL请求发送给MySQL进行处理。
5.Dubbo RPC通信过程中传递全局事务XID
BusinessService对StockService进行RPC调用时，会传递全局事务XID。StockService便可以根据RootContext.getXID()获取到全局事务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")//分布式事务如果5分钟还没跑完，就是超时
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机制)
Seata与Dubbo整合的Filter过滤器ApacheDubboTransactionPropagationFilter会将向SeataServer注册的全局事务xid，设置到RootContext中。
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
# Seata网络通信相关的配置
transport {
# 网络通信的类型是TCP
type = "TCP"
# 网络服务端使用NIO模式
server = "NIO"
# 是否开启心跳
heartbeat = true
# 是否允许Seata的客户端批量发送请求
enableClientBatchSendRequest = true
# 使用Netty进行网络通信时的线程配置
threadFactory {
bossThreadPrefix = "NettyBoss"
workerThreadPrefix = "NettyServerNIOWorker"
serverExecutorThread-prefix = "NettyServerBizHandler"
shareBossWorker = false
clientSelectorThreadPrefix = "NettyClientSelector"
clientSelectorThreadSize = 1
clientWorkerThreadPrefix = "NettyClientWorkerThread"
# 用来监听和建立网络连接的Boss线程的数量
bossThreadSize = 1
# 默认的Worker线程数量是8
workerThreadSize = "default"
}
shutdown {
# 销毁服务端的时候的等待时间是多少秒
wait = 3
}
# 序列化类型是Seata
serialization = "seata"
# 是否开启压缩
compressor = "none"
}
# Seata服务端相关的配置
service {
# 分布式事务的分组
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"
# 是否开启降级
enableDegrade = false
# 是否禁用全局事务
disableGlobalTransaction = false
}
# Seata客户端相关的配置
client {
# 数据源管理组件的配置
rm {
# 异步提交缓冲区的大小
asyncCommitBufferLimit = 10000
# 锁相关的配置：重试间隔、重试次数、回滚冲突处理
lock {
retryInterval = 10
retryTimes = 30
retryPolicyBranchRollbackOnConflict = true
}
reportRetryCount = 5
tableMetaCheckEnable = false
reportSuccessEnable = false
}
# 事务管理组件的配置
tm {
commitRetryCount = 5
rollbackRetryCount = 5
}
# 回滚日志的配置
undo {
dataValidation = true
logSerialization = "jackson"
logTable = "undo_log"
}
# log日志的配置
log {
exceptionRate = 100
}
}
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