API, in fact, is a function that has been written by others to achieve specific functions, and you only need to provide a good interface according to him, that is, call his method, pass in his specified parameters, and then this function will help you achieve these Function, probably the meaning of the empty glove white wolf, otherwise you can complete these functions yourself, but this is very difficult, because sometimes you need to understand a lot of principles and so on, if you are not a rule maker, then use these well Interface, in the end, if you are a good person, you can also provide api for others to use, and become a god in others’ mouths
You write a function for others to use, and others can call it directly.
But if you don’t want others to see your function logic, and don’t want to have limitations (you write a function in Java, the caller can call it in Python), you just wrap it up, use the http protocol, and then others pass you through URL to call your function
In fact, the interface is that simple.