JpaTemplate

Class Overview

Helper class that allows for writing JPA data access code in the same style as with Spring's well-known JdoTemplate and HibernateTemplate classes. Automatically converts PersistenceExceptions into Spring DataAccessExceptions, following the org.springframework.dao exception hierarchy.

The central method is of this template is "execute", supporting JPA access code implementing the JpaCallback interface. It provides JPA EntityManager handling such that neither the JpaCallback implementation nor the calling code needs to explicitly care about retrieving/closing EntityManagers, or handling JPA lifecycle exceptions.

Can be used within a service implementation via direct instantiation with a EntityManagerFactory reference, or get prepared in an application context and given to services as bean reference. Note: The EntityManagerFactory should always be configured as bean in the application context, in the first case given to the service directly, in the second case to the prepared template.

NOTE: JpaTemplate mainly exists as a sibling of JdoTemplate and HibernateTemplate, offering the same style for people used to it. For newly started projects, consider adopting the standard JPA style of coding data access objects instead, based on a "shared EntityManager" reference injected via a Spring bean definition or the JPA PersistenceContext annotation. (Using Spring's SharedEntityManagerBean / PersistenceAnnotationBeanPostProcessor, or using a direct JNDI lookup for an EntityManager on a Java EE 5 server.)

JpaTemplate can be considered as direct alternative to working with the native JPA EntityManager API (through a shared EntityManager reference, as outlined above). The major advantage is its automatic conversion to DataAccessExceptions; the major disadvantage is that it introduces another thin layer on top of the native JPA API. Note that exception translation can also be achieved through AOP advice; check out PersistenceExceptionTranslationPostProcessor.

LocalContainerEntityManagerFactoryBean is the preferred way of obtaining a reference to an EntityManagerFactory, at least outside of a full Java EE 5 environment. The Spring application context will manage its lifecycle, initializing and shutting down the factory as part of the application. Within a Java EE 5 environment, you will typically work with a server-managed EntityManagerFactory that is exposed via JNDI, obtained through Spring's JndiObjectFactoryBean.

Summary

[Expand] Inherited Fields
From class org.springframework.orm.jpa.EntityManagerFactoryAccessor protected final Log logger Logger available to subclasses

[Expand] Inherited Methods
From class org.springframework.orm.jpa.JpaAccessor void afterPropertiesSet() Eagerly initialize the JPA dialect, creating a default one for the specified EntityManagerFactory if none set. void flushIfNecessary(EntityManager em, boolean existingTransaction) Flush the given JPA entity manager if necessary. EntityManager getEntityManager() Return the JPA EntityManager to use. JpaDialect getJpaDialect() Return the JPA dialect to use for this accessor. boolean isFlushEager() Return if this accessor should flush changes to the database eagerly. void setEntityManager(EntityManager entityManager) Set the JPA EntityManager to use. void setFlushEager(boolean flushEager) Set if this accessor should flush changes to the database eagerly. void setJpaDialect(JpaDialect jpaDialect) Set the JPA dialect to use for this accessor. RuntimeException translateIfNecessary(RuntimeException ex) Convert the given runtime exception to an appropriate exception from the org.springframework.dao hierarchy if necessary, or return the exception itself if it is not persistence related Default implementation delegates to the JpaDialect.
From class org.springframework.orm.jpa.EntityManagerFactoryAccessor EntityManager createEntityManager() Obtain a new EntityManager from this accessor's EntityManagerFactory. EntityManagerFactory getEntityManagerFactory() Return the JPA EntityManagerFactory that should be used to create EntityManagers. Map<String, Object> getJpaPropertyMap() Allow Map access to the JPA properties to be passed to the persistence provider, with the option to add or override specific entries. EntityManager getTransactionalEntityManager() Obtain the transactional EntityManager for this accessor's EntityManagerFactory, if any. void setEntityManagerFactory(EntityManagerFactory emf) Set the JPA EntityManagerFactory that should be used to create EntityManagers. void setJpaProperties(Properties jpaProperties) Specify JPA properties, to be passed into EntityManagerFactory.createEntityManager(Map) (if any). void setJpaPropertyMap(Map<String, Object> jpaProperties) Specify JPA properties as a Map, to be passed into EntityManagerFactory.createEntityManager(Map) (if any).
From class java.lang.Object Object clone() boolean equals(Object arg0) void finalize() final Class<?> getClass() int hashCode() final void notify() final void notifyAll() String toString() final void wait() final void wait(long arg0, int arg1) final void wait(long arg0)
From interface org.springframework.beans.factory.InitializingBean abstract void afterPropertiesSet() Invoked by a BeanFactory after it has set all bean properties supplied (and satisfied BeanFactoryAware and ApplicationContextAware).
From interface org.springframework.orm.jpa.JpaOperations abstract boolean contains(Object entity) abstract <T> T execute(JpaCallback<T> action) abstract List executeFind(JpaCallback<?> action) abstract <T> T find(Class<T> entityClass, Object id) abstract List find(String queryString, Object... values) abstract List find(String queryString) abstract List findByNamedParams(String queryString, Map<String, ?> params) abstract List findByNamedQuery(String queryName, Object... values) abstract List findByNamedQuery(String queryName) abstract List findByNamedQueryAndNamedParams(String queryName, Map<String, ?> params) abstract void flush() abstract <T> T getReference(Class<T> entityClass, Object id) abstract <T> T merge(T entity) abstract void persist(Object entity) abstract void refresh(Object entity) abstract void remove(Object entity)