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Struts Framework

Struts Framework. Anna Pa ščenko. What is Struts?. An open source framework for building Java web applications. A Good Framework is…. A defined support structure in which another software project can be organized and developed. A Good Framework is….

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Struts Framework

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  1. Struts Framework Anna Paščenko

  2. What is Struts? • An open source framework for building Java web applications.

  3. A Good Framework is… • A defined support structure in which another software project can be organized and developed.

  4. A Good Framework is… • A defined support structure in which another software project can be organized and developed. • Allows to spend more time on meeting software requirements, not onmore tedious low level detailsof providing a working system.

  5. A Good Framework is… • A defined support structure in which another software project can be organized and developed. • Allows to spend more time on meeting software requirements, not onmore tedious low level detailsof providing a working system. • Provides proven and reliable design patterns and code architecture to an application.

  6. Java Web Frameworks • > 50 open source frameworks only • Struts • Tapestry • Spring • Cocoon • Maverick • Echo

  7. Struts • One of the most popular and widely used Java Web frameworks: • stable and mature • good documentation • large user community • open source • developed by industry experts • flexible and extendable

  8. Struts • Application architectures based on the Model 2 approach, a variation of the classic Model-View-Controller (MVC) design paradigm.

  9. MVC architecture • The MVC architecture divides applications into three layers: • model, • view, • controller

  10. MVC architecture • The MVC architecture divides applications into three layers: • model, • view, • controller • Each layer handles specific tasks and has specific responsibilities to the other areas.

  11. MVC architecture

  12. MVC architecture • A model • represents • business data and • business logic or operations that access and modify this business data • notifies views when it changes • provides the ability for the view to query the model about its state • provides the ability for the controller to access application functionality

  13. MVC architecture

  14. MVC architecture • A view • renders the contents of a model • accesses data from the model and specifies how that data should be presented • updates data presentation when the model changes • forwards user input to a controller

  15. MVC architecture

  16. MVC architecture • A controller • defines application behavior • an application typically has one controller for each set of related functionality • dispatches user requests • selects views for presentation • interprets user inputs and maps them into actions to be performed by the model

  17. MVC Model 2

  18. Struts MVC

  19. Struts MVC • Struts provides its own Controller component and integrates with other technologies to provide the Model and the View.

  20. Struts MVC • For the Model, Struts can interact with • standard data access technologies (JDBC, EJB), • most any third-party packages (Hibernate, iBATIS, Object Relational Bridge etc.).

  21. Struts MVC • For the View, Struts works well with • JavaServer Pages, including JSTL and JSF, • Velocity Templates, • XSLT, • etc.

  22. Struts Architecture

  23. Struts Controller Layer • ActionServlet • struts-config.xml • Action • ActionForward • ActionForm

  24. ActionServlet • Handles requests to a Struts application. • configured as Servlet in the web.xml file

  25. ActionServlet • Handles requests to a Struts application. • configured as Servlet in the web.xml file • specifies the url patternto be handled by the servlet

  26. ActionServlet • Handles requests to a Struts application. • configured as Servlet in the web.xml file • specifies the url patternto be handled by the servlet • uses the configuration defined in struts-config.xml file to decide the destination of the request

  27. struts-config.xml • <form-beans> • describes a particular form bean, which is a JavaBean that implements the org.apache.struts.action.ActionForm class

  28. struts-config.xml <form-beans> <!-- sample form bean descriptor for a DynaActionForm <form-bean name="logonForm“ type="org.apache.struts.action.DynaActionForm"> <form-property name="username" type="java.lang.String"/> <form-property name="password" type="java.lang.String"/> </form-bean> end sample --> </form-beans>

  29. ActionForm • Encapsulates the form properties. • Passed to an Action class methods as a parameter.

  30. struts-config.xml • <form-beans> • describes a particular form bean, which is a JavaBean that implements the org.apache.struts.action.ActionForm class • <global-forwards> • configures the global mappings of logical names to mappable resources

  31. struts-config.xml <global-forwards> <forward name="welcome" path="/Welcome.do"/> </global-forwards>

  32. ActionForward • Represents a destination to which the controller might be directed after finishing the processing activities. • Is a return value of the Action class methods.

  33. struts-config.xml • <form-beans> • describes a particular form bean, which is a JavaBean that implements the org.apache.struts.action.ActionForm class • <global-forwards> • configures the global mappings of logical names to mappable resources • <action-mappings> • contains action definitions

  34. struts-config.xml <action-mappings> <action path="/Login" type="myPackage.LoginAction" <forward name="forwardNext" path="/pages/NextAction.jsp"/> </action-mappings>

  35. ActionMapping • Stores the mapping information. • Passed to an Action class methods as a parameter.

  36. Action • The Struts framework provides an abstract Action class that you must extend for your own needs. • The ActionServlet calls the Action's execute() method to perform whatever task the Action class was meant to perform. • Within the overridenexecute() method, you can put in whatever logic you need in order to fulfill the request.

  37. Action public class LoginAction extends Action { /** * Called by the ActionServlet when the a user attempts to login. */ public ActionForward execute(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception { // Check username and password. return mapping.findForward("forwardNext"); } }

  38. Struts Examples • Several example applications are bundled with the Struts distribution: • Blank - A simple template for starting new Struts applications. • MailReader - The original Struts example application. • Examples - Various demonstration applications combined as separate modules.

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