[java] resttemplate library doesn't support API with response type:string and format:binary

• Use a openapi json that describes an API with the following configuration

responses:
        "200":
          description: Your request was successful
          content:
            application/json;charset=UTF-8:
              schema:
                type: string
                format: binary

• Use generator java with the following options

{
 "dateLibrary":"legacy",
 "library":"resttemplate"
}

• The client is not correctly generated to support the file download using Spring Rest Template framework.

ResponseEntity<T> responseEntity = restTemplate.exchange(requestEntity, returnType);

Where T is File and returnType is ParameterizedTypeReference<File>(). In this way File is treated as a json object to be mapped to the response.

An alternative piece of code must be generated to support the download of a generic binary stream to a tmp directory (like for example with the jersey2 library) and the use of class File as returned object to read that

Start with the generated RestTemplate client and the ResponseEntity exchange call shown in the report, then compare its binary download handling with the jersey2 library. Done means a response declared as string with format binary is downloaded to a temporary location and returned through File rather than JSON mapping.