(A primary business management system, user characters are divided into administrators, publishers, individual users and visitors. The first three have their own corresponding functions, and the administrator has the right to repair personal and user data and product information. Publishers have the right to publish products and change personal information. Individual users have the right to purchase products and repair personal information. Visitors only need to read. The project uses sqlite as the storage of stand-alone data, and the source code has specific comments. Can be used as graduation design source. The default administrator user name is javaapk password 123456)