Today, Anhui java course/will explore the layered types in software architecture.

I hope that by reading this article, you can have more knowledge and understanding of the field of software architecture.

Classic three-tier architecture: 1. Basic layer: dao, help class, IO reading and writing, resource loading and other infrastructure, which can be combined into business layer and service layer as the basic modules of the whole system. 2. Business layer and service layer: Service is typical, which carries more business realization, resource combination scheduling, transaction realization and so on. Here is the core of the whole system, and the following integrates the underlying dao and. According to the business and scenario, business logic and the underlying basic unit are flexibly spliced and combined to provide specific business processing logic for the presentation layer. 3. Presentation layer: accepting external requests, calling corresponding services to operate specific services, and feeding back the final results to callers or users. On the basis of the basic layer, it can be divided into one layer: domain layer, basic layer or providing basic data operation and IO and network operation. The domain layer encapsulates and integrates the basic layer again, with the purpose of facilitating the integration of the underlying resources, facilitating the call of the service layer and simplifying the complex dependence between the business layer and the basic layer. Static business object: the data object used in the ViewObject:VO interface displays the DomainObject:DO domain layer object, which can be simply understood as a javabean object. The basic model class BussinessObject:BO business object extracted from business is generally in the service business layer. If DO can't be fully expressed, you can use BO to express more information, or you can encapsulate persistan object:PO of entity information in reuse DO, which generally acts on the dao layer. DataTransferObject: DTO data transfer object corresponding to database entity is used to encapsulate parameters. Dynamic processing objects will be used in the list of transmission and reconstruction process methods in data: Controller controller, Manager management class, Service class, Repository, DAO data source, Client client, Dispather transponder, Handler processor, Interceptor Helper, Dynamic configuration files and properties of Utils help class: some commonly used switches and thresholds must be written in the configuration file or distributed by the configuration center, so don't write them in the program, there should be a refresh mechanism corresponding to api interface, and common configuration parameters should be forced to refresh after being called, such as: start and end dates of activities, large values in business, external URIs such as limit values, file upload addresses, Static resource location, etc. .....................................................................................................................................................