> For the complete documentation index, see [llms.txt](https://despend.gitbook.io/despend/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://despend.gitbook.io/despend/technical-architecture/instant-messaging-systems.md).

# Instant messaging systems

The client can achieve functions such as registration, instant messaging, file transfer between users, screenshot sharing, and viewing historical chat records. When sending messages, offline reception can be implemented. The server should establish a ServerSocket and continuously monitor for client connections or disconnections (including timeouts for unresponsive connections). 

As the information hub, the server receives all client data and distributes it according to requirements. In the backend management system, users can perform operations like adding, deleting, modifying, or querying accounts, viewing online users, and kicking users offline. 

(1) Technical Feasibility Using Swing and socket technologies, it's easy to develop a practical, simple, and efficient web-based instant messaging system. Therefore, this is technically achievable. 

(2) Economic Feasibility With widespread computer networks, significant investment in network infrastructure is unnecessary. The system requires a MySQL database server. Due to limited concurrent users, Tomcat can serve as the web server, keeping costs low. 

(3) Operational Feasibility As long as multiple computers are connected within the same LAN, this system can be installed and used without any operational issues. For internet communication, simply run the server on a public network with a fixed IP address.


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