cometta cometta - 25 days ago 23
Java Question

Spring multiple @Transactional datasources

<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="data.emf" />
</bean>

<tx:annotation-driven transaction-manager="transactionManager" />


<bean id="transactionManager2" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="data.emf" />
</bean>

<tx:annotation-driven transaction-manager="transactionManager2" />




In my service layer, can I use
@Transactional(name="transactionManager2");
to identify which transaction manager I use if I have multiple transaction managers?

Answer

You can specify which tx manager to use with @Transactional using the value attribute:

A qualifier value for the specified transaction.

May be used to determine the target transaction manager, matching the qualifier value (or the bean name) of a specific PlatformTransactionManager bean definition.

For example:

@Transactional("txManager1");

Alternatively, you can use the more explicit TransactionProxyFactoryBean, which gives you finer-grained control over what objects gets proxied by what tx managers. This still uses the annotations, but it doesn't auto-detect beans, it's configured explicitly on a bean-by-bean basis.

This normally isn't an issue, but it's not wise to have multiple transaction managers unless you have a very good reason to do so. If you find yourself needing two tx managers, it's usually better to see if you can make do with one. For example, if you have two data sources configured in your app server, you can incorporate both in a single JtaTransactionManager, rather than two seperate JpaTransactionManager or DataSourceTransactionmanagers.

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