The upgrade path from WebWork 2 to Struts 2 is smooth glide. Here's the roadmap.

System Platform

• Struts 2 is dependant on XWork 2 (beta-1).
• Java 1.5 is required to build Struts 2.
  • For Java 1.4 deployments, RetroTranslater JARS are available with the distribution.

For other changes from WebWork 2, see the "Members to rename", "New property settings", "New features or feature changes", and "Removed or deprecated" sections.

Members to rename

The tag prefix conventions in the example applications have changed.

New property settings

It is recommended that all applications specify the DynamicMethodInvocation setting for now, since the default may change. The recommended approach to action aliasing is to use wildcard aliases instead of the hardwired bang.

New features and feature changes

• Various changes to ConfigurationManager
  • ConfigurationManager is no longer a static factory. It is now an instance created through Dispatcher. Custom configuration could be done through DispatcherListener.
  • Custom configuration to ConfigurationManager and Configuration cannot be done statically anymore, instead use Dispatcher's DispatcherListener to achieve the same effect.
• The prepare interceptor now uses reflection to call prepare_Method_ where method is the action method configured for the particular action in struts.xml.

     <action name="myAction" method="insert" ....>
       .....
     </action>
  
     // with the above configuration, and PrepareInterceptor in play, 
     // callsequence will be 
     1] prepareInsert() (If it exists)
     2] prepare() (Unless Interceptor's alwaysInvokePrepare parameter is set to false)
     3] insert()
  

• DefaultWorkflowInterceptor (named workflow in struts-default.xml) now uses reflection to call validateMethod on the action class that implements Validateable interface where method is the action method configured for the particular action in struts.xml.

  <action name="myAction" method="insert" ...>
         ...
      </action>
  
      // with the above configuration, and DefaultWorkflowInterceptor in play, 
      // call sequence for action that implements Validateable interface will be 
      1] validateInsert()
      2] validate() (unless Interceptor's alwaysInvokeValidate parameter is set to false)
      3] insert()
  

• The tooltip library used by the xhtml theme was replaced by Dojo's tooltip component.
• Datepicker tag has been renamed to datetimepicker and is now using dojo (limited in terms functionality and internationalization)
• Tiles integration plugin is available.
• Wildcards can be specified in action mappings.
• MessageStoreInterceptor is introduced to allow field errors / action errors and messages to be store and retrieve through session, resulting them to be preservable across request.

Removed or deprecated

  <action name="..." method="submit">
    ...
  </action>