With the building blocks described above you can use Spring in all sorts of scenarios, from applets up to fully-fledged enterprise applications using Spring's transaction management functionality and web framework integration.
By using Spring's declarative transaction management
features the web application is fully transactional, just as it
would be when using container managed transactions as provided by
Enterprise JavaBeans. All your custom business logic can be implemented
using simple POJOs, managed by Spring's IoC container. Additional services
include support for sending email, and validation that is independent of
the web layer enabling you to choose where to execute validation rules.
Spring's ORM support is integrated with JPA, Hibernate, JDO and iBatis;
for example, when using Hibernate, you can continue to use your existing
mapping files and standard Hibernate
SessionFactory configuration. Form
controllers seamlessly integrate the web-layer with the domain model,
removing the need for
ActionForms or other classes
that transform HTTP parameters to values for your domain model.
Sometimes the current circumstances do not allow you to completely
switch to a different framework. The Spring Framework does
not force you to use everything within it; it is not
an all-or-nothing solution. Existing front-ends built
using WebWork, Struts, Tapestry, or other UI frameworks can be integrated
perfectly well with a Spring-based middle-tier, allowing you to use the
transaction features that Spring offers. The only thing you need to do is
wire up your business logic using an
ApplicationContext and integrate your web layer
When you need to access existing code via web services, you can use
classes. Enabling remote access to existing applications suddenly is not
that hard anymore.
The Spring Framework also provides an access- and abstraction- layer for Enterprise JavaBeans, enabling you to reuse your existing POJOs and wrap them in Stateless Session Beans, for use in scalable, failsafe web applications that might need declarative security.