Struts2 is a Java web framework that uses the model-view-controller pattern and consists of 3 core components: Actions, Results, and Interceptors. Actions handle user requests, Results define page transitions, and Interceptors provide extensibility through filters. The document discusses the components and plugins of Struts2, provides examples, and notes pros like extensibility and cons like confusing programming models.

1. Struts2 in a nutshell Shinpei Ohtani(shot6) http://twitter.com/shot6/

2. Agenda About me What is Struts? The big picture The 3 core components Struts2 plugin Struts2 Pros and Cons Struts2 resources

3. About me Shinpei Ohtani HN : shot6 or shot Works at ISI Dentsu, Ltd Web developer/Open source developer Java/ActionScript/JavaScript/Silverlight/C# Contact information Blog : http://d.hatena.ne.jp/shot6/ (Japanese) Twitter : shot6 Skype : shot_6

4. About me(continued) Open source activity T2 web framework Web framework for Web2.0 style application Go to http://code.google.com/p/t-2/wiki/Index?wl=en

5. What is Struts? Struts is Web framework for java web application Based on Servlet and JSP spec MVC pattern2 based architecture It is licensed Apache Software License2 Develop at http://struts.apache.org/

6. What is Struts1? Struts1 is The defacto standard since 2002 Front controller pattern from PofEAA XML configuration User only develop Action and ActionForm, and jsp Action is a template pattern for accepts user action ActionForm is a DTO as user request

7. What is Struts2? Struts2 is Totally different from Struts1! Current version is 2.1.6-ga. It’s based on WebWork Core engine is Xwork core Action-based model(could be POJO) No more create ActionForm because Action takes that roll. Filter and command pattern basically Plug-in architecture(so many plugins) Multi view templates

8. The big picture From http://struts.apache.org/2.1.6/docs/nutshell.html

9. The components 3 core components Action Result Interceptor

10. Action The Action for user action created by: Implements Action interface from Xwork2 Just create as POJO with methods: Should have String execute() method. Or declared by struts.xml Or use @Action from struts2-convention-plugin All the samples take implement Action way though….

11. Action(continued) Other things of Action are: Default Action extension is .action . Action can chain one to one. Action can be configured by xml configuration or annotation.

12. Action sample

13. Action configuration Login action(mailreader2.Login) Login_input -> /Login.jsp Login_cancel -> redirect to Welcome action Login_expired -> chain to ChangePassword action Exception mapping

14. Action config by annotation Annotations are: @Result for page transition @Action for action method name instead of juse execute @Actions for multiple names for just one method

15. Result Implements Result interface from Xwork2 All the result of Action.These are: ServletDispatcherResult(default) ServletRedirectResult StreamResult JasperReportsResult from jasper-report-plugin FreeMarkerResult ChartResult and so on….

16. Result(continued) Result is configured by xml <result name=&quot;login&quot; type=&quot;redirectAction&quot;>Login_input</result> Annotation @Result(name = &quot;list&quot;, value = &quot;listPeople.action&quot;, type = ServletRedirectResult. class)

17. Default Result

18. Interceptor Interceptor is the filter hook for Action like AOP. Implements Interceptor interface from XWork2 Struts2 extension is basically built on this. Struts2 itself is also implemented on Interceptors. It is like AOP around invocation Interceptor is called from ActionProxy

19. Interceptor(continued) Interceptor IS the extensibility of Struts2. Autowired with Spring Debugging Exception mapping File upload Token generator and validator Security checker

20. Interceptor(continued2) To use Interceptor: by xml configuration by annotation

21. Configuration Interceptor

22. Plugins So many Struts2 Plugins out there! Almost all is based on Interceptor Some of these is based on Result These plugins is configured by struts.xml

23. Convention plugin Execute CoC Converntion over configuration Zero configuration(they are saying…) Directory traverse by convention

24. Convention plugin(cont’d) Convention The class named XxxAction is treated as Struts Action. Example1 : examples.action.HogeAction Translate to /hoge.action Match “ action|actions|struts|struts2 ” as root package by default Then, “Action” removes from the name and make it lower case string(hoge) Add “.action” -> hoge.action

25. Convention plugin(cont’d2) Convention Example2 : examples.action.mine.MyAction Translate to /mine/my.action Example.action package is as the root Subpackage(mine) treats as url So here comes result : /mine/my.action

26. Convention plugin sample

27. Convention plugin sample

28. Convention plugin sample Without it, it won’t work at my sample.

29. REST plugin Handle REST-like request Inspired from Rails REST-like convention Builts on Convention plugin Example examples.hoge.FooController -> /foo If succeed, go foo-success.jsp If failed, go foo-failed.jsp

30. REST convention Handle REST-like request(Rails-like conv) GET: /movies => method=&quot;index” GET: /movies/Thrillers => method=&quot;show&quot;, id=&quot;Thrillers” GET: /movies/Thrillers;edit => method=&quot;edit&quot;, id=&quot;Thrillers” GET: /movies/Thrillers/edit => method=&quot;edit&quot;, id=&quot;Thrillers” GET: /movies/new => method=&quot;editNew” POST: /movies => method=&quot;create”

31. REST sample(Action)

32. REST sample(jsp)

33. REST sample(xml)

34. Struts1 plugin Use legacy Struts1 codes at Struts2 Struts1 Action and ActionForm works without change. Supports commons-validator

35. Struts1 config sample Set Struts1Action to handle Set actual Action class

36. Struts2 Pros and Cons Pros Very extensible if you know the architecture Many plugins are already developed so don’t have to develop your own Easy to collaborate with other template engine Work with jsp/freemarker/velocity So many view components

37. Struts2 Pros and Cons Cons Confused with many programming model.Should be one unified model. Over-used CoC which is not maintainable. Don’t think it’s good idea to have convention plugin Confused between Xwork and Struts2 Should be merged as one good product Configuration inheritance is not good idea XML in jar file is not easy to find

38. Struts2 resources Struts2 tutorials http://struts.apache.org/2.1.6/docs/tutorials.html Struts2 developer guide http://struts.apache.org/2.1.6/docs/guides.html Plugins http://struts.apache.org/2.1.6/docs/plugins.html

39. Thanks Enjoy with Struts2!!