Quartz 4

Spring 中的事务管理

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Spring 对事务支持源码流程图

Spring 中的事务管理

Transaction Management

xml 配置示例

Example of Declarative Transaction Implementation (XML): Example of Declarative Transaction Implementation

<?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:aop="http://www.springframework.org/schema/aop"  
      xmlns:tx="http://www.springframework.org/schema/tx"  
      xsi:schemaLocation="  
      http://www.springframework.org/schema/beans
      https://www.springframework.org/schema/beans/spring-beans.xsd
      http://www.springframework.org/schema/tx
      https://www.springframework.org/schema/tx/spring-tx.xsd
	  http://www.springframework.org/schema/aop
	  https://www.springframework.org/schema/aop/spring-aop.xsd">  
   <!-- service bean-->  
   <bean id="userService" class="org.yang.learn.spring.tx.BookService" >  
      <property name="jdbcTemplate" ref="jdbcTemplate"></property>  
   </bean>  
   <!-- dao bean-->  
   <bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate" >  
      <property name="dataSource" ref = "dataSource"></property>  
   </bean>  
   <!-- 数据源 bean-->  
   <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" >  
      <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"></property>  
      <property name="url"  
              value="jdbc:mysql://192.168.40.171:3306/workflow_test?serverTimezone=Asia/Shanghai&amp;characterEncoding=utf8&amp;useSSL=false"/>  
      <property name="username" value="user_dev"></property>  
      <property name="password" value="xxxx"></property>  
   </bean>   <!-- 事务管理bean-->  
   <bean id="transactionManager" class="org.springframework.jdbc.support.JdbcTransactionManager" >  
      <constructor-arg ref="dataSource"></constructor-arg>  
   </bean>  
   <aop:config>  
      <!--切点配置   -->  
      <aop:pointcut id="serviceOperation"  
                 expression="execution(* org.yang.learn.spring.dto.UserServiceImpl.*(..))"/>  
      <!-- 通知/增强 配置 (事务增强)-->  
      <aop:advisor pointcut-ref="serviceOperation"  advice-ref="txAdvice"/>  
   </aop:config>  
  
   <tx:advice id="txAdvice" transaction-manager="transactionManager">  
      <tx:attributes>  
         <tx:method name="get*" read-only="true"/>  
         <tx:method name="insertWithTransaction" propagation="REQUIRED"/>  
      </tx:attributes>  
   </tx:advice>  
</beans>

NESTED

如果有外部事务: 挂起外部的事务, 再创建新的内部事务
如果没有外部事务: 创建新的事务

in short 总是以嵌套的方式执行, 可以无限嵌套, 目的是每一层都是新事务

Spring JdbcTemplate 怎么支持声明式事务?

org.springframework.jdbc.core.JdbcTemplate 关键在于确保数据源中获取的 JDBC连接 都是同一个, 而在声明式事务配置中, 无论是 dataSource 对象, 还是 jdbcTemplate Bean 都没有被代理; 从配置上, 来看也完全没有关联

其实是 JdbcTemplate 在获取连接时 适配了 Spring 事务相关的代码, 关键源码:

  • org.springframework.jdbc.core.JdbcTemplate#execute(org.springframework.jdbc.core.CallableStatementCreator, org.springframework.jdbc.core.CallableStatementCallback<T>)
  • org.springframework.jdbc.datasource.DataSourceUtils#getConnection
  • org.springframework.jdbc.datasource.DataSourceUtils#doGetConnection
public static Connection doGetConnection(DataSource dataSource) throws SQLException {  
   Assert.notNull(dataSource, "No DataSource specified");  
	//从 TransactionSynchronizationManager 获取连接 (由Spring声明式事务处理的连接)
   ConnectionHolder conHolder = (ConnectionHolder) TransactionSynchronizationManager.getResource(dataSource);  
   if (conHolder != null && (conHolder.hasConnection() || conHolder.isSynchronizedWithTransaction())) {  
      conHolder.requested();  
      if (!conHolder.hasConnection()) {  
         logger.debug("Fetching resumed JDBC Connection from DataSource");  
         conHolder.setConnection(fetchConnection(dataSource));  
      }  
      return conHolder.getConnection();  
   }  
   // Else we either got no holder or an empty thread-bound holder here.  
   logger.debug("Fetching JDBC Connection from DataSource");  
   Connection con = fetchConnection(dataSource);
......

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