Java Reference
In-Depth Information
These POJO business components can be made available as distributed objects
through the various remoting options available with Spring. They can also be used to
develop as well as connect to distributed EJB components. With Spring AOP, it is possible
to transparently apply system services such as transactions, security, and instrumenta-
tion to POJO components. Spring JDBC and object-relational mapping (ORM)
components allow simplified interaction with databases. As an application framework,
Spring provides easy standards-based integration with disparate information systems
through Java Connector Architecture ( JCA) and web services. Last but not least, Spring
security is a comprehensive solution to cater to the security requirements of any
enterprise application.
Spring Framework's Building Blocks
Spring is an application framework and is divided into several modules or components.
Each module provides a specified set of functionality and works more or less independ-
ently of the others. Needless to say, these modules can be leveraged to build scalable yet
flexible enterprise Java applications. This system is very flexible, because developers can
choose to use only the module that is most appropriate in the context of a problem. For
example, a developer can just use the Spring DAO module and build the rest of the appli-
cation with non-Spring components. Moreover, Spring provides integration points to
work with other frameworks and APIs. If you think Spring is unsuitable in a particular
scenario, you can use alternatives. In case the development team is more proficient in
Struts, for example, it can be used instead of Spring MVC while the rest of the application
uses Spring components and features such as JDBC and transactions. In the two scenar-
ios described here, the developers need not deploy the entire Spring Framework. They
will require only the relevant module (like Spring DAO) along with the Spring IOC con-
tainer and the Struts libraries.
Figure 2-1 shows the various modules of the Spring Framework.
