如何理解 restful 中操作的无状态 “stateless”?

怎样用通俗的语言解释REST，以及RESTful？

From there, an API could be considered more "mature" as a REST API as it adopted the following ideas: Level 1: Resources (e.g. a resource-aware URL layout, contrasted with an opaque URL layout as in XML-RPC) Level 2: HTTP Verbs (using GET, POST, DELETE, etc. properly) Level 3: Hypermedia Controls (e.g. links) Level 3 is where the uniform interface comes in, which is why this level is considered the most mature and truly "The Glory of REST"