Applications With The Struts FrameworkSession WE06 – 11.ppt

Building Web Applications With The Struts Framework Session WE06 – 11/20/2002 – 10:00-11:00 Craig R. McClanahan Senior Staff Engineer Sun Microsystems, Inc. Session Outline Web Applications Backgrounder The Model-View-Controller Architecture The Struts Framework Building A Web Application With Struts Resources Web Applications Backgrounder Web Applications Backgrounder Web applications run over the HTTP protocol: Request/response oriented Stateless Web applications use varied presentation (markup) languages, and talk to varied client hardware devices: “Standard HTML” -- not! Varying dynamic and JavaScript capabilities Wireless devices vary in capabilities, language dialect, and input device support Simple Solutions ... for Simple Problems For relatively simple applications, a simple architecture works fine For each page in the user interface ... Create a servlet, JSP page, or something similar The page includes: Logic to create the user interface Logic to retrieve required information from the database Logic to perform the appropriate business transaction Logic to update the corresponding database information And its all mixed together in one source file This works fine for a Guest Book app, but what about something bigger? What About Large Scale Applications? Disparate skill sets required: Presentation Layer-- User interface design, visual appearance, interaction model Application Layer – Functional business logic to perform required transactions Persistence Layer – Databases, directory servers, messaging, Enterprise JavaBeansTM (EJBs) Application Deployment – Networks, firewalls, public key infrastructures, load balancing, failover We need a fundamental organizing principle: The Model-View-Controller (MVC) architecture The Model-View-Controller (MVC) Architecture The Model-View-Controller Architecture Divides the overall functionality of an application into three layers: Model Layer – Contains the functional business logic of the application, as well as a repr