Spring is a powerful Java application framework, used in a wide range of Java applications. It provides enterprise services to Plain Old Java Objects (POJOs). Spring uses dependency injection to achieve simplification and increase testability.
1. Spring provides a very clean division between controllers, JavaBean models, and views.
2. Spring’s MVC is very flexible. Unlike Struts, which forces your Action and Form objects into concrete inheritance (thus taking away your single shot at concrete inheritance in Java), Spring MVC is entirely based on interfaces. Furthermore, just about every part of the Spring MVC framework is configurable via plugging in your own interface. Of course we also provide convenience classes as an implementation option.
3. Spring, like WebWork, provides interceptors as well as controllers, making it easy to factor out behavior common to the handling of many requests.
4. Spring MVC is truly view-agnostic. You don’t get pushed to use JSP if you don’t want to; you can use Velocity, XLST or other view technologies. If you want to use a custom view mechanism – for example, your own templating language – you can easily implement the Spring View interface to integrate it.
5. Spring Controllers are configured via IoC like any other objects. This makes them easy to test, and beautifully integrated with other objects managed by Spring.
6. Spring MVC web tiers are typically easier to test than Struts web tiers, due to the avoidance of forced concrete inheritance and explicit dependence of controllers on the dispatcher servlet.
7. The web tier becomes a thin layer on top of a business object layer. This encourages good practice. Struts and other dedicated web frameworks leave you on your own in implementing your business objects; Spring provides an integrated framework for all tiers of your application.
8. No ActionForms. Bind directly to domain objects
9. More testable code (validation has no dependency on Servlet API)
10. Struts imposes dependencies on your Controllers (they must extend a Struts class), Spring doesn’t force you to do this although there are convenience Controller implementations that you can choose to extend.
11. Spring has a well defined interface to business layer
12. Spring offers better integration with view technologies other than JSP (Velocity / XSLT / FreeMarker / XL etc.)