The difference between poetry appreciation metaphor and metonymy is simple!

1. Metaphorically, two things are similar. Let's take A as an example of B, which needs no example.

2. Metonymy is a rhetorical way, which replaces what you want to express with related things. Remember, this rhetoric doesn't directly say who or what you want to say.

For example, Lei Feng's need for Lei Feng is metonymy, and political power out of the barrel of a gun is an abstract representation.