Lately i've been developing a Spring boot application with Angular 5 frontend and i got a little confused about the architecture of it. I was taught to write repositories, services and controllers in spring and to follow the MVC pattern. I started to write the documentation for the app and im trying to describe the arhitecture. So as i think View is the Angular app, C consists of the controller classes, and i described the third layer as buisniss logic which consists of the entity and service classes. But what is the Model really? Did i manage to follow the MVC pattern? In addition i have a controlleradvice, exception classes and security classes that make the authentication and authorization using jwts, but i guess these classes totally stay out from the MVC.
I've searched for the explanation but didnt seem to find it. Could someone please explain this to me? Thank you!
UPDATE
So basically what i dont understand is how the spring classes + angular meet the requirements of the MVC pattern
For example this is one of the first diagrams on the internet when you search for spring layers but as i see these are different from MVC
enter image description here
As mentioned in the comments, both your backend with Spring boot and your frontend with Angular can be seen as different applications, each following the Model-View-Controller design pattern.
You also posted a screenshot of the three-tier architecture. This type of architecture only tells you about how to structure your code. Typically, the MVC-part of your application is within the presentation layer (in your screenshot it's called the web layer).
So, if you would look at your backend application, you can identify the following parts:
Data tier/Repository layer: Repositories
Business tier/Service layer: Services
Presentation tier/Web layer: Model-View-Controller + Dispatcher
Model: Whatever you expose within your services (could be DTOs)
View: JSON structure/mapping
Controller: Spring controllers
And for your frontend you could identify them as well:
Data tier: HTTP calls
Business tier: Angular services
Presentation tier: Components + Router
Model: Whatever you expose within your services (probably a similar structure as the one you expose in your backend)
View: Templates
Controller: Components
This is a bit oversimplified though, and probably not something everyone will agree with.
I am working on the same project with angular as a frontend and spring boot as a backend, and i am still a little bit confused about it's architecture just like you, but i finally had to adopt the MVC model since i am actually using controllers, defining models and rendering views (the json results).
Obviously your front end uses a CBA (component based architecture and your backend is using an MVC pattern since spring MVC is embedded inside spring boot so it actually uses the same logic.
here's a brief image of how spring boot dispatches between controllers and handles requests, you can consider your dispatcher servlet as the middleware between your front end and your backend (but keep in mind that it is embedded inside the spring boot container)
Angular is an SPA, a single-page-application. It contains everything, Model (changing of business data), View (templates with HTML) and Controller (your click- and other event-handlers in your components).
The Spring backend is an extension of the Model, for performing further data transformation and storing it on a database.
The Model-View-Something (there is also MVVM and derivations) is a pattern that comes from desktop-applications, but it doesn't really fit in the world of SPAs. And the Controller in MVC is often seen as redundant even in desktop-applications (because it just delegates stuff and not taking as big role as View and Model).
Important for you to know when you work with Angular is rather the Component-pattern. It is valid in Angular, in React, Vue and even in Vaadin. A component is chunk of both HTML and script-code manipulating that HTML. And components can nest each other allowing a hierarchical architecture.
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I'm trying to learn dependency injection. The book/example I am following seems to be using an MVC project as just the UI layer within a broader architecture. The example includes a separate project for the domain layer and yet another project for the data access layer.
When I first learned MVC I came away thinking MVC was the entire architecture. V for view for UI layer, C for controller for domain layer, and M for model for data access layer.
So is using an MVC project as only the UI layer a proper and/or commonly accepted application of the MVC framework?
So is using an MVC project as only the UI layer a proper and/or commonly accepted application of the MVC framework?
Yes.
While it is possible to make an application entirely within the context of ASP.NET MVC, doing so means that the application will have to be written from scratch to use a different UI framework. Isolating the business logic into a separate set of services that are not coupled to ASP.NET MVC means that only the top layer would need to be replaced to move to a different UI framework, which also means that the application's lifecycle may extend beyond the end of ASP.NET MVC and/or it can be made into an application with a different UI framework (WebApi, WPF, etc) without too much trouble.
The purpose of dependency injection is to decouple your services from all other parts of the application, including each other. So by extension, it is only natural to build the business layer separately from the UI layer. Whether you physically have them in one assembly or multiple is really just a matter of preference.
Applying SRP to the MVC design pattern will lead you there. Same goes for MVVM. You are extracting logic from Model to other classes like Interactors, Services, Repositories etc.
From any point of view this is perfectly normal(and desirable). Your Model is just an abstraction of Several different layers.
I would suggest you to take a look at VIPER (not a car) - https://www.objc.io/issues/13-architecture/viper/ and you will see something that is occuring to you right now.
I have a design problem at hand. Traditionally I had been developing Spring MVC/Struts/jsf applications with either REST/SOAP service serving the data.
Now we have HTML5 and other javascript frameworks. In this light, do we still need to create Spring MVC applicationS as such (assume that the data is served from a RESTful service)
If I go ahead with pure HTML5, CSS UI (with Ajax calls to RESTful services), what are the possible issues that I may get into? does this approach have security holes like being prone to cross site scripting?
Is it a good approach to start off with? Would this approach be called a single page app?
You still need to serve your single page app from somewhere, along w images and css files. This could be a Spring MVC servlet, or whatever.
I'd look into Spring Data REST which is a servlet that creates RESTful HATEOAS endpoints for you.
It's probably easier if your SPA and REST service are on the same domain, so you don't have to worry about cross-domain restrictions.
They are still vulnerable to XSS, as is any system unless you take counter-measures. Spring security can help here. Make sure you follow the OWASP guidelines.
Use Hibernate Validator's #SafeHTML annotation to prevent unsafe HTML input into your database. Use Spring Security's <content-type-options/> , <xss-protection/> , and <header name="Content-Security-Policy" value="..."/> settings to help fight XSS.
Spring MVC, Struts, etc. provide two core functions: Routing, and Binding.
Routing is dispatching an HTTP request to the relevant piece of code.
Binding is converting the world of Strings that the HTTP request sends you in to something more useful, such as a generic Java bean with not just Strings, but integers and dates.
Along for the ride are aspects such as validation.
Finally, they provide an environment that's particularly friendly to your view layer.
None of these aspects, per se, are obsolete in a world where all you have is JSON coming up and JSON heading back. You still need routing, but now you may care to route not simply on the request url itself, but on HTTP verb. You still need binding, having the framework marshal the JSON payload into some easier for java to work with is very handy.
But, (and I speak in general terms, not specifics as I don't know Spring or Struts well at all), while the MVC frameworks can fill the role of a backend system for a more JSON oriented and raw HTTP world, the specific REST frameworks do the job better.
There's no mistake that the MVC frameworks were a significant step up over raw Servlets. Raw Servlets are functional, but simply too primitive for real work. But with design decisions made from a world 10 years ago, some parts show their age and get in the way in the new world of more raw HTTP requests.
If you're doing a mixed app, some MVC, and some HTTP/Ajax methods, then it's better to work with your MVC framework than adopt a new one.
If you're doing a pure singe page app, then it's worth your while to adopt a framework that tends to that niche. They'll simply be a better fit.
Mind, also, they can live side by side. You can have both co-habitate in a single WAR if you wish, particularly if you're adding SPA features to a legacy application. It doesn't have to be an either/or situation.
But I wouldn't introduce an entire new infrastructure component simply to handle a couple of ajax calls. In the end, they're just HTTP calls, and the MVC frameworks (in contrast to most component frameworks) do just fine with raw HTTP for the most part.
I currently have a web application that is based upon a 3 Tier architecture. I wish to change my Presentation layer from using Web Forms to MVC4.
Now I have done some research and from what I read I understood that the View represents the .aspx of a Web Form. The Controller represents the Code Behind (.cs) of a Web Form.
The problem that I have is that I do not see any use for the Model. This is because I can directly call methods from the Business Logic Layer directly from the Controller making the purpose of the Model useless.
Is there something that I am misunderstanding? If so what are you views on implementing an MVC design patter for the presentation layer in a 3 layer architecture?
In a simple application the model in MVC can simply be the DTOs from the Application or Business Layer. In this case you're right, you probably don't need a separate model in the UI.
An application is both JS intensive and has a complex business logic +huge data flow that uses backboneJS to structure JavaScript code and there is a necessity for the server side MVC also (Spring in this case).
Is it a good idea to implement server side MVC (spring ) along with client side MVC (backbone) and are there any compatibility issues between them?
In case both can be implemented.How am i going to coordinate the spring views with the backbone view.
How will client side MVC with template engine collaborate with 'View' of Spring.
Though this question has been asked before, I could not find suitable answer for this. Can somebody help me with a detailed answer?
Backbone.js is primarily used for SPA's (Single Page Applications). Your backbone.js segments ('views') are rendered and re-rendered by data, that is fetched or changed. If your application is going to be javascript intensive, backbone is a great minimal framework that will help organize your application. However, backbone is not so simple when your javascript application becomes quite large. You have to have a thorough understanding of the fundamentals of javascript and have a programming decided pattern. Otherwise you application can become quite a mess even with the use of backbone.js.
Anyhow I digress. Think of you client side application (backbone.js driven) completely separate from your server side application (MVC driven). All your client application needs from your server application is the data. That is why backbone.js is built around a REST API. If you are looking to develop a large javascript application, I would look at using MVC 4's Web API for your REST API, and backbone.js to help organize and standardize your client application.
This article describes how to make an application architecture with both server side MVC and JS MVC , respecting the MVC pattern.
http://blog.javascriptmvc.com/?p=68
I know that an MVC framework allows you to separate business logic, data base access and presentation, but why do we need a framework to do this.
Can't we just keep our classes separated, perhaps using different packages/folders for the model, view and controller classes?
In my opinion the thing you are talking about is the MVC pattern and not a specific framework. Of course you can go and keep all your classes within one project and still use the MVC pattern, as you have all your UI code in the views, the logic in the controllers, ...
A MVC framework on the other hand makes it easier for you to use this pattern. It may provide some base classes for controllers and a mechanism for the communication between view and controller.
I don't know if you are familiar with ASP.NET MVC. The framework itself is very small, but it helps you developing an application with the MVC pattern, as you don't have do think about the previously decribed areas...
Hope this helps
An MVC framework is a framework written to split up the the business logic, database access and presentation.
This is very useful in most web applications, and now lately into software/desktop applications.
This is due to the fact that following the MVC model, your code will be much clearer, cleaner and you keep your application DRY (Do not Repeat Yourself).
You can write your own classes and separate them into Model, View and Control. But again, you will need a framework to help you in accomplishing certain tasks. Like a List control in ASP.NET, or PHP framework being able to help you translate text between languages and so on. (Oh why reinvent the wheel?!)
MVC and framework is a different thing. MVC is just an architectural pattern, which can be applied with any project, with or without framework.
So you don't need a framework to do this. You can separate them by yourself. :)
MVC stands for “MODEL” “VIEW” “CONTROLLER”. ASP.NET MVC is an architecture to develop ASP.NET web applications in a different manner than the traditional ASP.NET web development. Web applications developed with ASP.NET MVC are even more SEO (Search Engine) friendly.
Developing ASP.NET MVC application requires Microsoft .NET Framework 3.5 or higher.
Model:
MVC model is basically a C# or VB.NET class.
A model is accessible by both controller and view.
A model can be used to
pass data from Controller to view.
A view can use model to display
data in page.
View:
View is an ASPX page without having a code behind file.
All page specific HTML generation and formatting can be done inside view.
One can use Inline code (server tags ) to develop dynamic pages.
A request to view (ASPX page) can be made only from a controller’s action method
Controller:
Controller is basically a C# or VB.NET class which inherits system.mvc.controller.
Controller is a heart of the entire MVC architecture.
Inside Controller’s class action methods can be implemented which are responsible for responding to browser OR calling views.
Controller can access and use model class to pass data to views
Controller uses ViewData to pass any data to view.
MVC is a code organization architecture style to organize your code-logic in a meaningful way for web applications. As a programmer I have almost puked when I have inherited other people's code when their code logic is all over the place and following their web application code turns into following a rabbit down the gutter hole. Why MVC? hmm.. well why should I use a filing cabinet or folders to organize my plethora of paper and not just have my papers stashed in a large pile and have others figure how they connect to each other. It increases code readability. With MVC it becomes very easy to follow code logic since you are following standard structure for a web application. Business logic is separated out from UI. Easier to delegate work decouple work on a project.
You can of course approach it yourself by segregating your classes. A framework supplies common scaffolding that you wouldn't have to build yourself. But it will also impose some structure on your code. You'll have to evaluate whether the framework helps more than it hurts.
You are correct, there are strategies that you can implement to help with separation of concerns without using MVC.
Microsoft's ASP.NET MVC framework is one strategy that can be employed, and that is what I think you are asking about.
This MVC framework makes such separation of concerns easy.
The other major advantage of MVC is testability - (depends on whether you believe in unit testing - I do).
The MVC framework ensures that all orchestration logic is on your controllers and through the FormControls collection allows full unit testing of all aspects of your application except for how it is presented.
As the MS MVC framework encourages adherence to common rules and structure of the application which should lead to greater maintainability.
The major downside of MVC is the code-in-front code weaving required for presentation, but this can be easily overcome.
Perhaps this is just a linguistic thing. I've seen "frameworks" referring to themselves as a DSL -- Domain Specific Language.
And you don't need a framework But here's something to consider: You already know for a web app you're going to want to do a few common things... route URLs, render pages, etc. Why re-write it all? For other problem domains you'll have generic things to do as well.
Hai Friends There are somemany types of architecture frame work has been there,firstly i know 2tier and 3 tier frame work ,the 3 tier and mvc ,entity framework are same but in different name's,so study a good background in any one architecture there fore if you went to any multinational companies ,you can easly score/highlight to your carrer.
Model View Controller or MVC as it is popularly called, is a software design
pattern for developing web applications. A Model View Controller pattern is made
up of the following three parts:
**Model** - The lowest level of the pattern which is responsible for maintaining data.
**View** - This is responsible for displaying all or a portion of the data to the user.
**Controller** - Software Code that controls the interactions between the Model and View