1. Struts 2 Development

2. Topics  Roles in Struts Development  Control Flow  Actions  Struts 2 Views and Target  Struts 2 Custom Tags  Validation  Form Submission  Error Handling  Resource Bundles  JSTL and JSF

3. Roles in Struts Development  Web Developer  Uses Struts custom tags, Java Server pages and sample files to create custom web apps  Uses XML, HTML, CSS, JSP and scripting languages to customize pages  Java Developer  programs in Java to develop Controller classes  develops Java Components (Servlets, JavaBeans, etc.) for multi-application use

4. The Controller  FilterDispatcher  Behaves like an Action factory

5. Control Flow Client Request FilterDispatcher Should an action be invoked? ActionMapper

6. Control Flow ActionProxy struts.xml FilterDispatcher ActionInvocation Look up Action class

7. Control Flow Action execute() ActionInvocation struts.xml Look up Result Code

8. The Action Class  POJO  Can contain an instance of the model as member variable because Action classes are instantiated for each request (thread-safe)  Override the execute() method public String execute()  Returns a simple String that serves as a symbolic name to determine what should happen next

9. Configuring the Action Class  Compile the new Action and put it in Web application’s classpath  Add an element to struts.xml  Several elements can use the same Action class as long as name attribute is different..

10. Struts 2 Views  Composed of JSPs, custom tag libraries, and ActionForm objects  JSPs  Present Data  Gather Data  Targets of Action result

11. JSP Targets  Action-Specific Forward <action.... Welcome.jsp Login.jsp 

12. Struts 2 Custom Tags  Tag Library: 

13. Struts 2 Custom Tags  Struts 2 utilizes FreeMarker to generate the markup for the tags.  FreeMarker can generate any type of markup: HTML, XSLT, WML, etc.

14. Validation  Validation is managed at the object level  Fields in an Action class can be checked through configuration file: -validation.xml

15. Validation Example LoginAction-validation.xml <!DOCTYPE validators PUBLIC “-//OpenSymphony Group//Xwork Validator 1.0.2//EN” http://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtdhttp://www.opensymphony.com/xwork/xwork-validator-1.0.2.dtd>

16. Struts 2 Form Submission  Form state/data combined with Action class

17. Struts 2 Error Handling  Establish ActionError tag on view  Use addActionError to accumulate message on ValueStack addActionError(getText(“error.login”));

18. Defining Resource Bundles  ResourceBundle is a file which contains a series of name/value pairs  Naming format is ResourceBundleName.properties  For example a file named ApplicationResources.properties might contain the entry error.age.invalid=Invalid Age

19. Deploying ResourceBundles  Place a copy of the resource bundles in the /WEB- INF/classes directory of your web application using appropriate package directory structure  Place the following entry in struts.xml

20. Retrieving Localized Messages  Web Page: key attribute  Java: getText() getText(“promptTitle”);

21. JSP Standard Tag Library (JSTL)  Establish a common set of custom tags  Create syntax that eliminates scripting within Web pages  Supports  Core operations (iteration, conditionals)  XML Processing  Internationalization formatting  Database access  The Jakarta Taglibs Standard 1.0 tag library is an implementation of JSTL 1.0.

22. JavaServer Faces (JSF)  Component model for building user interfaces for Web Applications  APIs for managing UI state, handling events and input validation, page navigation  JSP Custom tag library  Benefits  Ease-of-Use  Standardization  Device Independence

23. Review  Roles in Struts Development  Control Flow  Actions  Struts 2 Views and Target  Struts 2 Custom Tags  Validation  Form Submission  Error Handling  Resource Bundles  JSTL and JSF