Now, we understand the overall request flow and responsibility of each component in a typical Spring MVC application. However, this is not enough for us to build an online web store application. We also need to know the best practices to develop an enterprise-level web application. One of the best practices in a typical web application is to organize source code into layers, which will improve reusability and loose coupling. A typical web application normally has four layers: the presentation, domain, services, and persistence. So far, whatever we have seen, such as the dispatcher servlet, controllers, view resolvers, and so on, is considered a part of the presentation layer components. Let's understand the remaining layers and components one by one.