Springdoc, Openapi how to write Multipart/form-data, file upload interface

First go to the official document of Swagger:

https://swagger.io/specification/#schema

The SpringDoc version I use is 1.69
Reference content:

Special Considerations for multipart Content

It is common to use multipart/form-data as a Content-Type when transferring request bodies to operations. In contrast to 2.0, a schema is REQUIRED to define the input parameters to the operation when using multipart content. This supports complex structures as well as supporting mechanisms for multiple file uploads.

When passing in multipart types, boundaries MAY be used to separate sections of the content being transferred — thus, the following default Content-Types are defined for multipart:

• If the property is a primitive, or an array of primitive values, the default Content-Type is text/plain
• If the property is complex, or an array of complex values, the default Content-Type is application/json
• If the property is a type: string with format: binary or format: base64 (aka a file object), the default Content-Type is application/octet-stream

The translation is:

Special precautions for Multipart content

When transmitting the request body to the operation, Multipart/Form-Data is usually used as the Content-Type. Unlike 2.0, when using multiple parts, the mode is required, which is used to define the input parameters of the operation. This supports complex structure and supports multi -file upload mechanism.

When passing multiple parts, the boundary can be used to separate the various parts of the content that is being passed on. Therefore, the following default content type is defined for multiple parts:

• If the attribute is the base of the base element or the element value, the default Content-Type is Text/PLAIN
• If the attribute is complex or a complex value, the default Content-Type is Application/JSON
• If the attribute is Type: String, the format is: binary or format: base64 (also known as File object), then the default Content-Type is Application/OCTET-Stream

Example Examples:

requestBody:
  content:
    multipart/form-data:
      schema:
        type: object
        properties:
          id:
            type: string
            format: uuid
          address:
            # default Content-Type for objects is `application/json`
            type: object
            properties: {}
          profileImage:
            # default Content-Type for string/binary is `application/octet-stream`
            type: string
            format: binary
          children:
            # default Content-Type for arrays is based on the `inner` type (text/plain here)
            type: array
            items:
              type: string
          addresses:
            # default Content-Type for arrays is based on the `inner` type (object shown, so `application/json` in this example)
            type: array
            items:
              type: '#/components/schemas/Address'

According to the above instruction
(You can change the commonresult to string)

@Operation(summary = "upload files")
@PostMapping("/files/upload")
@RequestBody(content = {@Content(
    mediaType = "multipart/form-data",
    schema = @Schema(type = "object"),
    schemaProperties = {
        @SchemaProperty(
            name = "multipartFile",
            schema = @Schema(type = "string",format = "binary")
        ),
        @SchemaProperty(
            name = "info",
            schema = @Schema(type = "object")
        )}
)})
public CommonResult<String> upload(MultipartFile multipartFile,
                     String info){
    return CommonResult.success(multipartFile.toString() + info);
}

http: // localhost: 8888/v3/api-docs:

{
  "/files/upload": {
    "post": {
      "tags": [
        "File Management"
      ],
      "summary": "upload files",
      "operationId": "upload",
      "requestBody": {
        "content": {
          "application/form-data": {
            "schema": {
              "type": "object",
              "properties": {
                "file": {
                  "type": "string",
                  "format": "binary"
                },
                "info": {
                  "type": "object"
                }
              }
            }
          }
        }
      },
      "responses": {
        "200": {
          "description": "OK",
          "content": {
            "*/*": {
              "schema": {
                "$ref": "#/components/schemas/CommonResultString"
              }
            }
          }
        }
      }
    }
  }
}

Swagger-UI:

Send requests and responses:

success!

Summary: The official documentation must be carefully read