I am looking for a good tutorial on migrating from struts to spring. I have multiple struts actions that I would like to refactor into spring components.
Here's one (assuming you're talking about Struts 1, although you don't specify).
Not sure how helpful it will be; depending on how clean the original Struts code was it could be relatively straight-forward, or brutal.
In my experience the bulk of the work lies in the JSPs, not the actions themselves, particularly if the S1 code made extensive use of the Struts tags. The actions themselves are easier to deal with because of strong IDE support.
Related
I have a Struts 1 application and I am exploring different options for upgrading the system. One option is Spring MVC or Spring Boot. If I were to choose either framework to migrate the application to, can I do so transitionally (piece by piece) or would it be a complete wholesale change or complete rewrite. Don't know if I'm making myself understood.
Spring 3.0, had explicit support for integrating struts 1. This was two major versions of spring and 9 years ago. There is documentation here:
https://docs.spring.io/spring/docs/3.0.5.RELEASE/reference/web-integration.html#struts
Integration consisted in either using the ContextLoaderPlugin to allow spring to manage all your action classes, or to make your action classes aware of the spring context. A fair amount of struts specific code was available to do things like map struts action handlers to action beans in the spring context.
You could probably reproduce a lot of this in spring 5, but you'd have to do a lot of heavy lifting on your own. There are probably very few struts/spring 5 users out there to help you.
You could also go with spring 3.0 to make the integration easier, allowing you to do the migration in steps, but then you are in a different bad place. You have an old version of spring that fewer people use, and none of the goodness that 9 years of releases have wrought.
If you want to migrate your struts 1 app to spring, you are probably going to have to do it all at once. Redo your action classes as springmvc controllers and then rewrite your views (templates). spring mvc is pretty view agnostic and there are many good choices.
Good luck and have fun!
I've inherited an incomplete but small web project (Java EE 5, running on WebSphere 7).
The project consists mostly of JSPs that are accessed directly via their URL, and most JSPs look up their own reference to the EJBs (services) they need. Also, there's a Servlet for every form that gets submitted by the HTML code in the JSPs.
Architecturally speaking, is there anything wrong with this?
I was thinking it would be better to have an MVC design. I don't want to convert everything to JSF because I don't want to convert all the HTML and embedded Java scriptlets into JSF tags and managed beans.
I don't really want to use Struts or Spring MVC because they're not part of the Java EE 5 toolkit that comes out of the box with WebSphere, and I don't want to add additional complexity with the additional libs and config files.
I was thinking about building my own little MVC with a "ControllerServlet" that accepts a command and dynamically build and execute the command object, and redirect to the JSP view.
But I ask myself again, is there anything "wrong" with JSPs that post to Servlets? It's actually kind of elegant in its simplicity.
What do you think?
Any suggestions are GREATLY appreciated! Rob
You're asking a rather subjective/localized question. But ala.
There's technically nothing wrong with individual JSPs that submit to individual servlets. The only real problem is when the servlets turn out to contain duplicated code for quite common tasks like collecting request parameters, converting/validating them, setting bean properties, invoking actions, performing navigation. That is not DRY and is what a MVC framework with a single front controller and a well definied lifecycle is supposed to solve.
Or, if the servlet's tasks are actually well refactored with homegrown code to perform those common tasks, then this is in turn not very maintainable as no one else than the original developer knows the ins and outs of this custom framework. So it's hard to find anyone else willing to maintain this webapp without learning another framework again which the new developer wouldn't likely to see in other future webapps. That is why companies usually adopt an existing and well-developed MVC framework like JSF, Spring MVC, Stripes, Struts, etc.
I m a newbie & i m good at Struts framework. Today i tried a tutorial for Spring MVC Framework.
The example url that i tried following is as below:
http://static.springsource.org/docs/Spring-MVC-step-by-step/part6.html
I think they have made this tutorial much more complex especially near its end. I saw some errors mainly typos in part 5, part 6 of tutorial. I found Spring framework as not properly organized and how would we know what classes to extend especially when their names are so weird (pardon my language) e.g. AbstractTransactionalDataSourceSpringContextTests.
Overall i found that Spring is making things much more complex than it should be. I'm surprised why there is such a hype about Springs being very easy to learn.
any suggestion how to learn spring easily ? how to judge what to extend ? is there a quick reference or something?
The tutorial you have referred to covers all the layers of the application - data access, business logic and web. For someone who is looking to only get a feel of Spring MVC, which addresses concerns specific to the web layer of the application, this could be more information than required. Probably that is why you got the feeling that the tutorial is complex.
To answer your questions, Spring is easy to learn because the whole framework is designed to work with POJOs, instead of relying on special interfaces, abstract classes or such. Developers can write software as normal Java applications - interfaces, classes and enums and use Spring to wire the components up, without having to go out of the way to achieve the wiring. The tutorial you have referred to tries to explain things in a little bit more detail than experienced programmers would typically do in a real application, probably because the authors wanted the readers to get enough insight into how Spring works so that concepts are understood well.
In most applications (regardless of their size or nature), there is typically no need to extend Spring classes or to implement specialised classes. The Spring community is quite large and an even larger ecosystem of readily available components exists that integrate with Spring. It is therefore very rare that one has to implement a Spring component to achieve something. For example, let us take the example of the data access layer. Different teams like using different approaches to accessing databases. Some like raw JDBC, others like third-party ORMs like iBatis or Hibernate while some others like JPA. Spring distributions contain classes to support all these approaches. Similarly, lets say someone was looking to incorporate declarative transaction management in their application. Again, transaction management can be done in many different ways and a large number of transaction management products are available for people to use. Spring integration is available for most of these products, allowing teams to simply choose which product they want to use and configure it in their Spring application.
Recent Spring releases have mostly done away with extensive XML based configuration files, which being external to the Java code did make Spring application a bit cumbersome to understand. Many things can be done nowadays with annotations. For example,
#Controller
public class AuthenticationController
{
...
}
Indicates that AuthenticationController is a web MVC controller class. There are even ways to avoid using the Controller annotation and follow a convention-over-configuration approach to simplify coding even further.
A good and simple tutorial to Spring MVC is available at http://www.vaannila.com/spring/spring-mvc-tutorial-1.html. This tutorial uses XML based configuration for Spring beans instead of annotations but the concepts remain the same.
I have seen tutorial you follow , Its seems you have follow wrong one first , you first tried to simple one, Instead of tutorials you should go for book first
I recommend you two books to understand the power of Spring
spring in action and spring recipes.
For practical you can use STS a special ide for spring project development.Its have some predefined template you dont't need to write whole configuration yourself.
In starting just see simple tutorials like Spring mvc hello world , form controller than go for big ones
Spring is very cool , All the best.
I am learning Java EE and wanna build up a complete management system for a restaurant. Now I am confused what presentation layer should I use for my RMS because I heard that the struts 2 is one of the best UI layer but, the thing is, if I am using spring for my business logic layer then I can use the spring MVC can't I? By the way, I am really interested to build a complete application which is follow the multi-tier architecture.
Yes, of course you can use Spring MVC.
You can use Struts 2 if you'd like as well, because Spring integrates with it nicely.
But I don't see any reason why you'd want to do that. The person who told you that Struts 2 is
one of the best UI layer [sic]
is misguided. If you compare it to Spring MVC, you'll see that the two are based on similar ideas, but Spring improves on Struts. JSF has superceded Struts as the default Java EE web view technology, so it's not even considered "best" by the Java EE standard.
Stick with Spring. You won't be sorry.
I will not blame struts 2, indeed it's a great product, I work with it every day. But in my experience spring MVC is a lot simpler and clearer. This doesn't mean you don't get as much features.
Try both, and you'll see what I mean.
Tell us which one you choose!
Scenario: A fairly mature project uses Struts2 and Spring and Hibernate. I say mature because it has been going on a for a while and there are many struts actions written already.
Suppose we wanted to remove Struts2 from the project and instead depend entirely on Spring MVC without rewriting the entire project.
Is this something that should even be considered?
Are there any migration guides out there?
Has anyone done this before and would like to warn me against it?
If it ain't broke, don't fix it. You have very likely better things to do than a migration that won't add any value to the product (and will certainly introduce some bugs). If I were the business, I would never buy such a migration (with close to zero benefits).
I have to ask: What advantages do you see with Spring MVC that aren't being fulfilled by Struts 2?
If there's not at least a handful of "smoking hot" features, or the amount of time saved is more than enough to overcome the time taken for the migration in the first place then it's probably best to stick with what you have.
You can do it slowly. Struts is a MVC framework. The rest of your application (business and data tiers) are classes which can be invoked by action classes. Struts is a plugin based architecture and it is easy for you to define a plugin in struts configuration file.
Take a look at this link. This may help.
With Struts2 security vulnerabilities being exposed and reported often, this task takes on more importance.