The Spring Framework provides integration with NHibernate in terms of resource management, DAO implementation support, and transaction strategies. For example for NHibernate, there is first-class support with lots of IoC convenience features, addressing many typical NHibernate integration issues. All of these support packages for O/R (Object Relational) mappers comply with Spring's generic transaction and DAO exception hierarchies. There are usually two integration styles: either using Spring's DAO 'templates' or coding DAOs against the 'plain' NHibernate APIs. In both cases, DAOs can be configured through Dependency Injection and participate in Spring's resource and transaction management.
You can use Spring's support for NHibernate without needing to use Spring IoC or transaction management functionality. The NHibernate support classes can be used in typical 3rd party library style. However, usage inside a Spring IoC container does provide additional benefits in terms of ease of configuration and deployment; as such, most examples in this section show configuration inside a Spring container.
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