OpenAPI Specification

符合OpenAPI规范 接口变更时，我们只需要更改对应的OpenAPI描述文件 让我们能专注于业务代码的开发

基础的OpenAPI描述文件

• openapi version
• info description
• paths restfull

paths endpoint（interface）

• Path Item Object (sub path route)
• Operation Object (medthod)
• Responses Object (status description content)

#### Responses  Content 
*  The Content Field （application/json  text/html）
*  The Schema Object  （Field: type）



#### 示例

openapi: 3.1.0
info:
  title: Tic Tac Toe
  description: |
    This API allows writing down marks on a Tic Tac Toe board
    and requesting the state of the board or of individual squares.
  version: 1.0.0
paths:
  # Whole board operations
  /board:
    get:
      summary: Get the whole board
      description: Retrieves the current state of the board and the winner.
      responses:
        "200":
          description: "OK"
          content:
            application/json: # 响应体格式
              schema:
                type: object # 响应体是个object
                properties:  # 它的属性有:
                    winner:  # winner,类型为string
                      type: string
                      enum: [".", "X", "O"] # winner的值只能为. X 或 O中的一个
                      description: |
                        Winner of the game. . means nobody has won yet.
                    board: # board属性
                      type: array # 类型为数组
                      maxItems: 3 # 最大3个元素
                      minItems: 3 # 最小3个元素
                      items:
                          type: array # 数组的元素依然是数组
                          maxItems: 3 # 最大三个元素
                          minItems: 3 # 最小三个元素
                          items:
                            type: string # 这个数组的元素为string
                            enum: [".", "X", "O"] # 值只能为. X或O
                            description: |
                              Possible values for a board square.
                              . means empty square.
  ...