DI: Useful when just starting out?

[Keith Fiske]

I've only recently started getting into Struts development and when I asked for some advice to see if I was on the right path with my initial development, someone responded I might want to look into incorporating things like Dependency Injection into my design.

I've only just learned about DI. How important is it for someone just getting into web application development to start incorporating it? My application is working fine so far without me specifically designing it in. Should I consider going back now and trying to work it in, or wait til I'm more comfortable with designing in Struts and then go back and see where it may be more useful?

[David Newton]

Like I said--it's probably not important yet. But IMO it's critical for testability, if nothing else.

[Hong Anderson]

I recommend you to try to use it. You don't need to go back, you can continue using Struts and try DI maybe by using Spring Framework at the same time.

[Jimmy Clark]

Keith, since you just started with Struts-based GUI development, I would suggest that you stay focused on learning Struts. You can learn about the Dependency Injection design pattern, and once you truly understand how it can be effectively applied, then you might incorporate it in the business applications that you create.

The Struts framework is very solid and there is very little that you can alter here.

[Dhanji Prasanna]

I hope you mean Struts2 and not Struts (avoid the latter at all costs!)

As James says, it is important to learn the principles behind DI and they will help you later in your career. However splitting your attention between too many things as you are just starting out may not be ideal. Perhaps learn about it, but decide whether you need to apply it at a later stage.

[Keith Fiske]

Yes, I'm starting with Struts2

Thanks all for the responses!

[Hong Anderson]

I agree that you should learn concepts of DI before applying it. But please keep in mind that sooner you apply it lesser your work (it case you want to refactor to use DI later).
You have to analyze what is better between 1) Higher cost at first and low cost later and 2) Lower cost at first but higher cost later.