类 LocalEntityManagerFactoryBean

public class LocalEntityManagerFactoryBean
extends AbstractEntityManagerFactoryBean

FactoryBean that creates a JPA EntityManagerFactory according to JPA's standard standalone bootstrap contract. This is the simplest way to set up a shared JPA EntityManagerFactory in a Spring application context; the EntityManagerFactory can then be passed to JPA-based DAOs via dependency injection. Note that switching to a JNDI lookup or to a LocalContainerEntityManagerFactoryBean definition is just a matter of configuration!

Configuration settings are usually read from a META-INF/persistence.xml config file, residing in the class path, according to the JPA standalone bootstrap contract. Additionally, most JPA providers will require a special VM agent (specified on JVM startup) that allows them to instrument application classes. See the Java Persistence API specification and your provider documentation for setup details.

This EntityManagerFactory bootstrap is appropriate for standalone applications which solely use JPA for data access. If you want to set up your persistence provider for an external DataSource and/or for global transactions which span multiple resources, you will need to either deploy it into a full Java EE application server and access the deployed EntityManagerFactory via JNDI, or use Spring's LocalContainerEntityManagerFactoryBean with appropriate configuration for local setup according to JPA's container contract.

Note: This FactoryBean has limited configuration power in terms of what configuration it is able to pass to the JPA provider. If you need more flexible configuration, for example passing a Spring-managed JDBC DataSource to the JPA provider, consider using Spring's more powerful LocalContainerEntityManagerFactoryBean instead.

NOTE: Spring's JPA support requires JPA 2.0 or higher, as of Spring 4.0. JPA 1.0 based applications are still supported; however, a JPA 2.0/2.1 compliant persistence provider is needed at runtime.