How to inject JPA EntityManager using spring

Question

Is it possible to have Spring inject the JPA entityManager object into my DAO class without extending JpaDaoSupport  If yes  does Spring manage the transaction in this case   I m trying to keep my Spring configuration as simple as possible    lt bean id  transactionManager  class  org springframework orm jpa JpaTransactionManager  gt       lt property name  entityManagerFactory  ref  em   gt   lt  bean gt   lt bean id  em  class  org springframework orm jpa LocalEntityManagerFactoryBean  gt       lt property name  persistenceUnitName  value  myPU   gt   lt  bean gt

User · Answer

Is it possible to have spring to inject the JPA entityManager object into my DAO class whitout extending JpaDaoSupport? if yes, does spring manage the transaction in this case?

This is documented black on white in 12.6.3. Implementing DAOs based on plain JPA:

It is possible to write code against the plain JPA without using any Spring dependencies, using an injected EntityManagerFactory or EntityManager. Note that Spring can understand @PersistenceUnit and @PersistenceContext annotations both at field and method level if a PersistenceAnnotationBeanPostProcessor is enabled. A corresponding DAO implementation might look like this (...)

And regarding transaction management, have a look at 12.7. Transaction Management:

Spring JPA allows a configured JpaTransactionManager to expose a JPA transaction to JDBC access code that accesses the same JDBC DataSource, provided that the registered JpaDialect supports retrieval of the underlying JDBC Connection. Out of the box, Spring provides dialects for the Toplink, Hibernate and OpenJPA JPA implementations. See the next section for details on the JpaDialect mechanism.

User · Answer

The latest Spring   JPA versions solve this problem fundamentally   You can learn more how to use Spring and JPA togather in a separate thread

User · Answer

Yes  although it s full of gotchas  since JPA is a bit peculiar  It s very much worth reading the documentation on injecting JPA EntityManager and EntityManagerFactory  without explicit Spring dependencies in your code   http   static springsource org spring docs 3 0 x spring-framework-reference html orm html orm-jpa  This allows you to either inject the EntityManagerFactory  or else inject a thread-safe  transactional proxy of an EntityManager directly  The latter makes for simpler code  but means more Spring plumbing is required

[java] How to inject JPA EntityManager using spring

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