mybatis中事務的管理和集成spring后如何將事務交給spring管理

　　　1.mybatis中事務的管理

　　　　SqlSessionFactory開啟一個SqlSession后，會給當前sqlsession注入事務工廠TransactionFactory：

　　　　

private SqlSession openSessionFromDataSource(ExecutorType execType, TransactionIsolationLevel level, boolean autoCommit) {    
 Transaction tx = null;
try { final Environment environment = configuration.getEnvironment(); final TransactionFactory transactionFactory = getTransactionFactoryFromEnvironment(environment); tx = transactionFactory.newTransaction(environment.getDataSource(), level, autoCommit); final Executor executor = configuration.newExecutor(tx, execType); return new DefaultSqlSession(configuration, executor, autoCommit); } catch (Exception e) { closeTransaction(tx); // may have fetched a connection so lets call close() throw ExceptionFactory.wrapException("Error opening session. Cause: " + e, e); } finally { ErrorContext.instance().reset(); } } 　　
//事務的生產交給TransactionFactory

  private TransactionFactory getTransactionFactoryFromEnvironment(Environment environment) {
    if (environment == null || environment.getTransactionFactory() == null) {
      return new ManagedTransactionFactory();
    }
    return environment.getTransactionFactory();
  }

 

 

所以mybatis事務的生產由TransactionFactory生產，該類是個接口，而具體實現才是執行真正邏輯的地方，在spring集成mybatis中，SpringManagedTransactionFactory實現了該接口，由此將mybatis的事務管理交給了spring進行管理

實現交接的邏輯：

  <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="mapperLocations" value="classpath*:*.xml"/>
    </bean>

在spring中配置的SqlSessionFactoryBean會執行afterPropertiesSet方法，該方法會初始化SqlsessionFactory,並且設置TransactionFactory為SpringManagedTransactionFactory

 

 <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.*.**"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
    </bean>

而MapperScannerConfigurer會執行postProcessBeanDefinitionRegistry方法，實現Mapper接口的代理，並將代理對象交給spring容器管理