dao层的一个工具类，实现加载、关闭驱动、增删改统一方法(Dao layer of a tool class, to achieve loading, closing the drive, additions and deletions to the same method)

dao层的一个工具类，实现加载、关闭驱动、增删改统一方法(A tool class in the Dao layer to implement a unified method of loading, closing, driving, adding and deletions)