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Common J2EE Design Patterns

There are a common set of design patterns for the J2EE platform.
Intercepting filter--This pattern applies to request pre- and post-processing of request. It applies additional services needed to process a request. For example, an intercepting filter such as a servlet filter may handle all incoming requests to the Web site and provide a central mechanism for authorization. View helper--A view helper encapsulates the presentation and data access logic portions of a view, thus refining the view and keeping it simpler. Presentation logic concerns formatting data for display on a page, while data access logic involves retrieving data.
View helpers are often JSP tags for rendering or representing data and JavaBeans for retrieving data. Composite view--This pattern makes view presentation more manageable by creating a template to handle common page elements for a view. Often, Web pages contain a combination of dynamic content and static elements, such as a header, footer, logo, background, an…