The article illustrates Separation of Concerns beyond AOP by refactoring a reconciliation service that mixes WeChat Pay and Alipay SDK calls with business logic, introducing a wrapper layer with custom types to isolate SDK-specific parsing from core matching rules, enabling independent evolution of each concern.
The article explains that returning a Result wrapper from the Service layer mixes business logic with presentation concerns, leading to tighter coupling, reduced reusability, cumbersome error handling, harder testing, poorer DDD alignment, limited interface flexibility, and ambiguous transaction boundaries.
Backend development underpins every software application, and mastering practices such as input validation, robust error handling, separation of concerns, and thorough testing and documentation ensures applications are secure, maintainable, and scalable, empowering developers to build resilient server‑side systems.
The article explains layered (n‑tier) architecture as a universal software design pattern, detailing its purpose, typical four‑layer structure, design considerations, advantages, and drawbacks such as limited agility, deployment challenges, and potential for the sinkhole anti‑pattern, while offering guidance for effective implementation.
The article explains why maintainable, human‑readable code matters for evolving software, outlines core concepts like high cohesion and low coupling, details the SOLID and other practical principles, and describes common refactoring techniques to improve readability and flexibility.
This article explains why scalability is essential for web apps and outlines core architectural principles—separation of concerns and horizontal scaling—along with practical server roles, load balancing, CDN usage, and worker processes to handle high traffic efficiently.
