Multiple database Schema with Spring+Hibernate+JPA - spring

Question

I have same database schema database_1 and database_2 and want to configuration of these two database(database schema is same) and decide run time which database is use.
My persistence.xml is as below:
<persistence-unit name="first" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>com.model.AboutUs</class>
<class>com.model.AccessCards</class>
<properties>
<property name="hibernate.dialect" value="com.util.customMySQLDialect" />
<property name="hibernate.hbm2ddl.auto" value="none" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.cache.provider_class" value="org.hibernate.cache.HashtableCacheProvider" />
<property name="hibernate.jdbc.batch_size" value="20"/>
<property name="hibernate.cache.use_query_cache" value="true"/>
<property name="hibernate.cache.use_second_level_cache" value="true"/>
</properties>
</persistence-unit>
Persistence name second configure here as below :
<persistence-unit name="second" transaction-type="RESOURCE_LOCAL">
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<class>com.model.AboutUs</class>
<class>com.model.AccessCards</class>
<properties>
<property name="hibernate.dialect" value="com.util.customMySQLDialect" />
<property name="hibernate.hbm2ddl.auto" value="none" />
<property name="hibernate.show_sql" value="true" />
<property name="hibernate.cache.provider_class" value="org.hibernate.cache.HashtableCacheProvider" />
<property name="hibernate.jdbc.batch_size" value="20"/>
<property name="hibernate.cache.use_query_cache" value="true"/>
<property name="hibernate.cache.use_second_level_cache" value="true"/>
</properties>
</persistence-unit>
Both persistence units load same classes .
and now my database-configure.xml as where i configure persistence unit with data source. as below first persistence unit name configare with datasource name datasource as :
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="persistenceUnitName" value="first" />
<property name="persistenceXmlLocation" value="classpath*:META-INF/persistence.xml"/>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
</property>
</bean>
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<property name="driverClass" value="${datasource.driverClassName}" />
<property name="jdbcUrl" value="${datasource.url}" />
<property name="user" value="${datasource.username}" />
<property name="password" value="${datasource.password}" />
<property name="acquireIncrement" value="1" />
<property name="acquireRetryAttempts" value="1" />
<property name="maxIdleTime" value="300" />
<property name="maxPoolSize" value="20" />
<property name="minPoolSize" value="3" />
<property name="maxStatements" value="300" />
<property name="testConnectionOnCheckin" value="true" />
</bean>
Now this code for configure second persistence unit name with data source name datasource5 as below :
<bean id="transactionManager5" class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory5" />
</bean>
<bean id="entityManagerFactory"
class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource5" />
<property name="persistenceUnitName" value="second" />
<property name="persistenceXmlLocation" value="classpath*:META-INF/persistence.xml"/>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
</property>
</bean>
<bean id="dataSource5" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
<property name="driverClass" value="${datasource.driverClassName}" />
<property name="jdbcUrl" value="${datasource5.url}" />
<property name="user" value="${datasource5.username}" />
<property name="password" value="${datasource5.password}" />
<property name="acquireIncrement" value="1" />
<property name="acquireRetryAttempts" value="1" />
<property name="maxIdleTime" value="300" />
<property name="maxPoolSize" value="20" />
<property name="minPoolSize" value="3" />
<property name="maxStatements" value="300" />
<property name="testConnectionOnCheckin" value="true" />
</bean>
Now i use entity manager for save data in database and i am using mysql database . I got entity manager with persistence unit name first and second .
#PersistenceContext(unitName="first")
private EntityManager entityManager;
#PersistenceContext(unitName="second")
private EntityManager entityManager2;
Now entity manager save data in database using persist( object) method successfully .
entityManager.persist(project);
and entityManager2 save data in database using persist( object ) method successfully (No Exception here). But data does not store in database datbase_2 .
entityManager2.persist(project);
If I change the order of persistence unit first and second in persistence.xml then entityManager2 save data in database and entitymanager does not save data in database .
Any one have idea how i can make multiple entitymanager for same database schema .

Answer 1

There are a few limitations:
#Transactional corresponds to single TransactionManager.
JpaTransactionManager corresponds to single EntityManager(Factory).
Thus use separate methods with #Transactional annotation for each transaction manager:
#Transactional(transactionManager = "tmBeanName")
After that entity managers will work fine.
Also, some workaround exists to break the second limitation (DO NOT USE IT in this case):
It is possible to use single JtaTransactionManager instead of several JpaTransactionManager: distributed transaction will cover both entity managers and they will work fine too.