I created a web application using Spring Boot for Backend and Angular 8 for Frontend with the help of the JHipster framework. The frontend communicates with the backend using a REST API.
I know that both Spring and Angular use of the MVC model. As such, in the case of Spring :
the database, JPA classes, and repositories are the Model
the REST Controllers are the Controller
My question is: what is the View part in the Spring application? My guess is that the entire Angular application takes the role of the view. Is that correct?
The view part in Spring was popular due to the Spring MVC concept where the view comprised of JSP (Dynamic) and HTML (Static) pages.
As you rightly said Spring and Angular both are MVC based frameworks, but now the current trend is moving towards Microservices architecture instead of Monololithic architecture.
Microservices architecture is language independent for its operation and communicates using REST services.
Currently, the focus is on separation of concerns and how quickly the code can be delivered.
1. Angular framework handles the UI part
2. Spring framework handles the backend operations (Business logics, interactions with the database and other servers.
In spring framework the MVC means
Model - The class that carries data
View -The view page (JSP/HTML)
Controller - The class that manages the operation
As you said on the post The database, JPA classes, and repositories are the Model these are nothing but the repository pattern which is integrated with the MVC pattern to communicate with the database.
To start Angular does not use MVC, Angular uses MVVM (model-view-view-model) or MVW (model-view-whatever)
Secondly your backend uses the n-layer pattern
Service Layer: Implement business logic
Data Access Objects: These are abstractions that your service layer will call to get / update the data it needs. This layer will generally either call a Database or some other system (eg: LDAP server, web service, or NoSql-type DB)
Controller Layer: Which will receive client requests.
In other words, you have a client-server architecture, with an n-layer pattern, where the angular (view layer) uses the MVVM pattern.
Observation:
Your Model you use may or may not come from your services. You may want to take the results your service gives you and manipulate them into a Model that's more specific to your medium (eg: a web page).
differentiate between database models (dao - data access object) and transfer model (dto - data transfer object)
Related
In regards to the MVC-pattern and the three-layer architecture, I'm a bit confused.
I know the difference between the two, but let's take an example of a java web project. Where we have a JSP-component, Servlet, Java Bean and a connection to a Database.
Is my understanding correct, that in the MVC-pattern, the JSP-page is the view that is presented to the user, the controller is the servlet that handles the request sent to the view, and the model is the objects (for example a java bean), that is sent through the controller to display dynamic content on the JSP-page.
Where is the three-tier architecture both the JSP, and Servlet component is the presentation layer, since that is what is being processed and displayed to the user, whereas the logic-tier is the java beans, where the methods of calculations are being processed, and the data tier, is the database along with the components of the JDBC?
Three tier is simple, you have a client, a server, and a database.
In the web world its a browser, a server(An example being a java application), and some sort of data store(Like a MySql server).
MVC is a design pattern used within an application that takes data and creates a presentation of that data. You can actually have it within every layer of a three tier architecture but it is most common within the server tier. In a single page application you may have a MVC in the client code, although, most client side frameworks take different approaches when compared to classic MVC.
I am considering moving from server-side rendering view technologies like JSP, Struts to client-side rendering view technologies using AngularJS,
A popular Javascript framework for modern browsers.
When we are making this change and what are all the things that I may encounter.
If anybody who are experienced in Spring Web MVC and JSP development and would know how Spring MVC can work together with a client-side Javascript like AngularJS.
Kindly Answer.
You have to rewrite the view part using angularJS, and replace the logic from the server with a REST API.
It's often a huge work, and the hardest part is to migrate the existing server-side session management to the browser, because a REST API is stateless.
Below is one of the suggested way in which i recently migrated my existing spring MVC web-application in Single page application using AngularJs as client side java-script framework:
1).First you needs to bisect your core business logic which must needs to handle in DB layer,if not done already. i.e. SP's,trigger's,etc...
2).Then for the thing mentioned as hardest by Toilal ("to migrate the existing server-side session management to the browser, because a REST API is stateless"), you can consider Spring Boot as one of the options to build things quickly instead of Spring MVC with fusion of java8 features to yield the JSON response via API's.
3).And than last but not the least, build UI layer with AngularJS in front End encapsulating the data returned by the spring boot API's. Please note that as angular is super power full, you can do most of your business logic at client side,your DB layer just needs to give you the whole bunch of business data to render the screen,other things you can easily handle in angular.
Thus, this way by making the DB layer thin and imbibing angular at front end, you can improve performance of your existing application drastically.
You can also check this AngularJS with Spring-mvc useful thread in same context.
I want to develop an enterprise level application using spring MVC in presentation layer and spring in Business Logic Layer and hibernate in data access layer.
But i want to keep the presentation layer in a web server, multiple business logic layer in multiple server and data access layer in another physical server that means i want to establish a n tier solution using spring mvc.
I am able to separate the layer in my architecture. But the problem is my solution is just work on a single server. I cant do a architecture for multiple physical server.
Suppose that, from controller i use #Autowired annotation to inject the object of business logic layer. But how can i establish a system where controller talks to business logic layer over the network and business logic layer talks to data access layer over network as well.
If anyone can describe the solution in details then it would be very helpful for me.
Thanks...
You should be able to divide your code quite easily. Let's call your data access layer a "Data Provider" service and business logic layer "Business Service".
Now, you have to decide what kind of network protocol are you going to use.
These days REST is the most popular one and also it is very easy to setup your REST endpoints with Spring MVC (use #RestController on the server and RestTemplate on the client). You can also use RMI if you want to really couple your services (Data Provider and Business Service) using the same Java code (interfaces, DTOs etc.)
We are developing an Enterprise application with the following technology stack:
Websphere Application Server
Spring (Webflow (Session in View pattern), JPA (Hibernate), Core)
DB2 osZ
Frontend (JSP Rendering HTML5 (CSS 2.0), Ajax in combination with webflow, JQuery)
Multiple Single Pages design combined by using webflow for supporting
subflows
Development Methodology
- Domain Driven/Component Driven Application
- Test Driven Development
Current Situation
Our domain model has very deep domain class hierarchy and therefore we decided to use webflow to allow deep class navigation in sub flows.
We are using the “session in view pattern” because there are many screens reflecting the class hierarchy of the domain model.
This worked very well because of having the backend managing session scoped data for the frontend.
What do we want to do next?
Single Page Design
Control User data in session
Control User data across screens
Support multiple instance of a browser in one user session
Want to be able to talk to the backend (Enterprise Java/Spring) to
retrieve data and persist
Support more state-of-art user experience
Technology Stack
Websphere Application Server
Spring (Webflow (Session in View pattern), JPA (Hibernate), Core)
DB2 osZ
Frontend (Angular, JQuery, Bootstrap 3)
So the discussion internally is how to integrate Angular?
Should we give up Webflow and solve everything with Angular?
Does a mix make sense?
We have taken the following chart as a reference:
http://vschart.com/compare/angularjs/vs/spring-framework
We know what both frameworks are able to do, and know how to make them work. We are interested in other teams experience on how to integrate Angular? Did someone ever mix Webflow and Angular?
We are interested to see some best practices and how teams have transitioned to either framework or keeping both?
Thanks for input,
Andrew
I suggest you to check the Java library thymeleaf in order to get directly the benefits of HTML5 which you can easily add AngularJS and build on top of it (with bootstrap if you need it), and use Spring Security for Auth & session management.
As loose coupling at all levels (front-end included) is most of the times desirable, try to avoid technology mixing (WebFlow & AngularJS in this case) where doesn't makes sense.
Last thing, you and your team can discuss the possibility to develop an Angular based single page application which consumes a server side API coded in Java.
It is too late but might be useful for someone looking for this sort of answer.
I would recommend
Angularjs SPA(single page application) and use html template instead jsp.
Implement Token based authentication rather session based and implement restful spring web mvc api.
web flow/navigation can be controlled using the Angular services or browser's localstorage. I would recommend Angular services to manage app state instead browser localstorage.
And obviously bootstrap 3 to make the UI pretty.
Example implementation: jhipster
I am preparing a document for a project. The project's backend is developed in Java, frontend is adobe flex.
I am not sure about the correct way of describe the project in Model-View-Controller way.
For Model layer: Using Hibernate Java beans to implement all the business logic and persistence?
For View Layer: Using Adobe flex send post or get request to Controller layer, and get respond in XML format.
For Controller Layer: Using Java servlet to handle requests from Flex client?
Thanks
Hibernate - Model
Flex - View
Servlets - Controller
Brief lift of complete nice article follows:
Model, is the data. Manipulates the internal state and fire events when the internal state changed.
View, the visual representation for the Model’s data (controls on the screen)
Controller, is responsible for interpreting the user actions on the view and make changes to the model. (usually an event handler in flex)
In reality there is no 100% demarcation between these three layers. Is not that easy to make them completely decoupled and usually we end up making some tradeoffs.
The controller will always know about the view and the view about the controller. Controller also knows about the model. In the end I could say that the model is the only piece of the MVC that can be “100% decoupled”.
You should check out the Adobe sponsored Cairngorm Framework for your Flex application. It's arguably the entire MVC design pattern in itself. Hibernate, Servlets, and your Java Beans are your application tier. There are other Flex MVC frameworks as well. Check out this other stackoverflow article for alternatives: Flex MVC Frameworks
The basic concept of Cairngorm is this:
Model: A singleton ModelLocator which stores the data that the Model needs to read from.
View: Your MXML/AS files that render the Model above.
Controller: The singleton FrontController that registers business events to a Command. The Commands represent a specific business logic task with associated logic/processing. This is usually where your API calls go to the Application tier to execute logic, fetch data, etc. When the Command is done, the Model is updated and your view will reflect those changes in the Model.
I could go in grave detail, but all of this information is described very well in the Cairngorm article linked above.