[BUG][SPRING] Different in-parameter types generated for api and delegate

Created by: easymindster

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?

Description

When using the maven plugin to generate java code for spring using the delegate pattern, the API differs between the API and the delegate. The generated API gets a body of type Resource, but the delegate is generated with the type MultipartFile, see below. The expected in-parameter type would be a Resource.

    @ApiOperation(value = "Upload content", nickname = "apiUpload", notes = "", response = Resource.class, tags={  })
    @ApiResponses(value = { 
        @ApiResponse(code = 200, message = "OK", response = Resource.class) })
    @RequestMapping(value = "/upload",
        produces = { "application/octet-stream" }, 
        consumes = { "application/octet-stream" },
        method = RequestMethod.PUT)
    default ResponseEntity<Resource> apiUpload(@ApiParam(value = "" ,required=true )  @Valid @RequestBody Resource body) {
        return getDelegate().apiUpload(body);
    }

Generated code for the delegate:

    default ResponseEntity<Resource> apiUpload(MultipartFile body) {
        return new ResponseEntity<>(HttpStatus.NOT_IMPLEMENTED);
    }

openapi-generator version

openapi-generator-maven-plugin, v.4.3.1

OpenAPI declaration file content or url

openapi: '3.0.2'
info:
  title: Test API
  version: "0.0.1"
servers:
  - url: http://localhost:8080/test  
paths:
  /upload:
    put:
      summary: "Upload content"
      operationId: apiUpload
      requestBody:
        required: true
        content:
          application/octet-stream:
            schema:
              type: string
              format: binary
      responses:
        '200':
          description: OK
          content:
            application/octet-stream:
              schema:
                type: string
                format: binary   

Generation Details

Extract from pom.xml:

         <plugin>
           <groupId>org.openapitools</groupId>
           <artifactId>openapi-generator-maven-plugin</artifactId>
           <version>4.3.1</version>
           <executions>
             <execution>
               <id>generate-rest-api</id>
               <phase>generate-sources</phase>
               <goals>
                 <goal>generate</goal>
               </goals>
               <configuration>
                 <inputSpec>${project.basedir}/src/main/resources/openapi/testapi.yml</inputSpec>
                 <generatorName>spring</generatorName>
                  <modelPackage>${default.package}.openapi.test.model</modelPackage>
                  <apiPackage>${default.package}.openapi.test.api</apiPackage>
                  <invokerPackage>${default.package}.openapi.invoker</invokerPackage>
                 <configOptions>
                   <sourceFolder>src/gen3/java/main</sourceFolder>
                   <validateSpec>true</validateSpec>
                   <java8>true</java8>
                   <dateLibrary>java8</dateLibrary>
                   <interfaceOnly>false</interfaceOnly>
                   <delegatePattern>true</delegatePattern>
                 </configOptions>
               </configuration>
             </execution>
           </executions>
         </plugin>         

Steps to reproduce

Use maven to generate the sources, i.e. mvn clean generate-sources

Related issues/PRs

None found.