1. Introduction to Spring Framework
Spring provides a lightweight solution for JavaEE development, mainly as follows:
- The core mechanism of IOC (or DI) provides a bean factory (Spring container), which reduces the complexity of business object replacement and improves the decoupling between components;
- AOP centrally manages some common tasks, such as security, transactions, logs, etc., which improves the reusability and the convenience of management;
- ORMs and DAOs provide good integration with third-party persistence layer frameworks, simplifying underlying data access;
- Provides an excellent Web MVC framework
It can be said that Spring is a framework that runs through the presentation layer, business layer, and persistence layer, providing a one-stop solution for javaEE. In addition, using Spring has the following advantages
- low intrusion design, extremely low code pollution;
- applications based on the Spring framework, It can be independent of various application servers, realize write once, run anywhere;
- Spring can be well integrated with third-party frameworks (such as ORM, DAO and other modules integrated with other frameworks), but at the same time Spring provides a high degree of openness, applications will not be Forced dependence on Spring, developers can freely choose part or all of Spring
2. Spring Architecture
The Spring framework exists in sub-modules. Except for the core Spring Core Container (ie, the Spring container), which is a necessary module, other modules are optional, depending on the needs. The architecture diagram of the
official document Spring 4.0 includes more than 20 modules. These sub-modules can be roughly divided into four categories: 1) Core Container (Core Container) 2) Data Access and Integration (Data Access/Integration) 3) Web 4) AOP