Java design mode job

Second: single-column mode

The above two can be used to realize: instantiation of classes.

Third: on-off.

The main entity classes are bean, dto and so on.

Also, the shopping system can query logistics and decide which logistics to query according to the internal status of the order: the status mode can be used.

Finally, to be honest, many web frameworks use many patterns. If you write it yourself, it is basically MVC mode. Basically, you just need to write action, server and dao, and you don't need any patterns.