Migrating to Struts 2, Part 2; First Struts 2 Dev Build Released
In the first part of the article series, Ian explained (for Struts developers) the high level architecture, basic request workflow, configuration semantics and differences in the action framework in the new Struts 2 (formerly WebWork) and Struts 1. In this part of the Struts 2 migration series, Struts committer Ian Roughely looks at a real application and compares the Struts and Struts 2 implementations, identifies how to convert actions, configuration changes, and what parts of the codebase don't need to be converted.
Read Migrating to Struts 2, Part II, published today.
According to the Struts 2.0.1 release announcement, some key changes are:
- Improved Design - All Struts 2 classes are based on interfaces. Core interfaces are HTTP independent.
- Intelligent Defaults - Most configuration elements have a default value that we can set and forget.
- Enhanced Results - Unlike ActionForwards, Struts 2 Results can actually help prepare the response.
- Enhanced Tags - Struts 2 tags don't just output data, but provide stylesheet-driven markup, so that we can create consistent pages with less code.
- First-class AJAX support - The AJAX theme gives interactive applications a significant boost.
- Stateful Checkboxes - Struts 2 checkboxes do not require special handling for false values.
- QuickStart - Many changes can be made on the fly without restarting a web container.
- Easy-to-test Actions - Struts 2 Actions are HTTP independent and can be tested without resorting to mock objects.
- Easy-to-customize controller - Struts 1 lets us customize the request processor per module, Struts 2 lets us customize the request handling per action, if desired.
- Easy-to-tweak tags - Struts 2 tag markup can be altered by changing an underlying stylesheet. Individual tag markup can be changed by editing a FreeMarker template. No need to grok the taglib API! Both JSP and FreeMarker tags are fully supported.
- Easy cancel handling - The Struts 2 Cancel button can go directly to a different action.
- Easy Spring integration - Struts 2 Actions are Spring-aware. Just add Spring beans!
- Easy plugins - Struts 2 extensions can be added by dropping in a JAR. No manual configuration required!
- POJO forms - No more ActionForms! We can use any JavaBean we like or put properties directly on our Action classes. No need to use all String properties!
- POJO Actions - Any class can be used as an Action class. We don't even have to implement an interface!
What will be the version number for the first Production quality release of Struts 2?
Re: Version Numbers
A bit confused...
Firstly, thanks for writing the article. I enjoy reading through it.
I have a question regarding what you wrote in this 2nd tutorial, in particular about the "ModelDriven" interface. From the sample code, it seems that this interface specifies the "getModel()" method. When does this method gets called (which presumably by the framework itself - i think)?
"Now, instead of finding a setter on the action, the model is first retrieved and checked to see whether it has a setter matching the attribute name. If there is no such setter on the model object, but there is on the action, then the value will be set on the action."
--> Isnt the model null initially? The framework wants to call setId().. and it
tries to do so on the model first. But the model gets initialized on the prepare() method. But looking at your prepare() method, it needs the "blogId", which is initialized on the setId() method. So by that time, "blogId" is null, and hence.. everything does not work. I'm sure I'm missing an important point here. It would be great if you can enlighten me :)
As this article was about converting application, it made sense to provide the XML configurations - as this is what most people using Struts would be farmiliar with.
Re: A bit confused...
The interceptor stack for the action in question is the "paramsPrepareParamsStack". The interceptors for this stack go like this... (1) params - to apply parameters to the action (so the id is set on the action), (2) prepare - to call the prepare() method using the id that has been previously set, and then (3) params again to set the values on the model.
Please note that there is a little redundancy here, as the action and possibly the model will not have the setters for the parameters that are trying to be set against them.
PS - Sorry for the delay in answering, I have been on vacation.
Re: A bit confused...
I tried by implementing ModelDriven intercpetor as in struts2 tutorial but in vain to get them into the action class.
Please help me.
source code missing classes.
Re: source code missing classes.
Re: A bit confused...
Forward to the action in Struts 2
But in article is this solution for forwarding to list.action
I think in struts 2 is better to write
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