When comparing Flask vs Spring MVC, the Slant community recommends Flask for most people. In the question“What are the best backend web frameworks?” Flask is ranked 4th while Spring MVC is ranked 12th. The most important reason people chose Flask is:
Even though it's pretty minimalistic out of the box, Flask still provides the necessary tools to build a quick prototype for a web app right after a fresh install. With all the main components pretty much packed in the `flask` package, building a simple web app in a single Python file is as easy as it gets.
Ranked in these QuestionsQuestion Ranking
Pro Extremely easy to build a quick prototype
Even though it's pretty minimalistic out of the box, Flask still provides the necessary tools to build a quick prototype for a web app right after a fresh install. With all the main components pretty much packed in the
flask package, building a simple web app in a single Python file is as easy as it gets.
Pro Lots of resources available online
Flask is one of the most popular Python web frameworks, if not the most popular one. As such, there's plenty of guides, tutorials, and libraries available for it. A large number of important Python libraries, such as SQLAlchemy have libraries for Flask, which add valuable bindings to make the development process and the integration between these libraries and Flask as easy as possible.
Pro Minimalist without losing power
Flask is very easy to get up and going, with vanilla HTML or with bootstrap pieces. It doesn't take much lines of Python to load Flask to get headers working, etc, and since it's all modular you don't have to have something you don't want in your application.
Pro Very flexible
Flask gives developers a lot of flexibility in how they develop their web applications.
For example, the choice of not having an ORM, but instead choosing one suited to the task, or another area where Flask gives a lot of options to developers is the templating. They can use Jinja2, Flask's default templating language or choose from a number of different templating languages they desire.
Pro Great documentation
The official documentation is very thorough and complete. Everything is explained in-depth and followed by extremely well-explained tutorials that tackle real-world problems.
Pro Spring MVC has a massive community
Being the oldest and most used JVM web framework, means that Spring MVC has a massive community of followers who are very helpful and have provided numerous tutorials and answers on SO.
Spring even holds an annual conference called SpringOne. The Spring forums and SO are great places to ask and get help about anything Spring related. The website blog and newsletter keep developers informed on every news related with the framework.
Pro Spring apps are highly scalable
Applications are meant to scale as the framework is used in large-scale applications worldwide. Components like EhCache are used to scale memory cache and it also contains components used for parallel processing.
Batch enables processing of large volumes of records and job processing statistics.
Pro Great documentation that covers almost everything.
The official documentation covers virtually everything. The official website also has a series of great tutorials in video and text formats. There are links to Github repositories for Spring sample applications and there are also a lot of third-party tutorials out there for the fact that Spring MVC is so widely used by many experienced developers.
Pro Spring has an extensive ecosystem
It is based and is dependent on the Spring Framework, therefore it benefits from tools like for example Roo and Spring Tool Suite and many more tools included in the Spring Framework. All Maven dependencies are available in a public Maven repository.
There are also 3rd-party solutions for Spring, such as MyEclipse which includes scaffolding capability for Spring MVC.
Con Not async-friendly
Flask is explicitly not designed to handle async programming.
Con Threadlocals and globals used everywhere
The default way of creating applications in flask makes it hard to use reusable and clean code.
Con Setting up a large project requires some previous knowledge of the framework
Setting up a large project with Flask is not that easy considering how there's no "official" way of doing it. Blueprints are a useful tool in this regard but require some additional reading and are a bit tricky to get right for a beginner.
The lack of some defaults can also be problematic. Having to choose between different libraries for a certain task is never easy, especially if you have never worked with Flask before.
Con Lacking in UI development
While actually very good and with a very complete and rich feature set to develop and maintain code on the server side, it still doesn't provide any rich framework for building good user interfaces.
Con Updating and code maintenance can be a grueling task if you are a beginner.
Updating your project is manageable if you’re already familiar with the framework and the project itself, but if you’re just diving in it can be a little overwhelming and hard.
Con Complex and not newbie friendly
Spring MVC architecture although simple has a lot of layers and abstractions which can be hard to debug if problems arise. It is also highly dependant on the Spring core.
It's an old and mature framework that has numerous amount of ways to extend and configure it – and this actually makes it fairly complex.
Con Bloated legacy DI API
Spring DI is bloated and rather complex in comparison to CDI.
Con Slow Prototyping
If you are looking to build a quick prototype fast and easy, Spring isn't going to help much. It's very large and quite hard to grasp if you are just beginning with it.