[BUG][Java][webclient] Json string in query param not supported

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?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

template : Java/webclient

Description

we get an api with a query param defined as a json string value. Example http://host/api?filter=[{"name":"john"}]

The swagger file is defined as :

swagger: '2.0'
  /doc:
    get:
      operationId: GetDoc
      produces:
        - application/json
      parameters:
        - name: filter
          in: query
          type: string
          description: 'like [{"name":"john"}]'

When we run the generated code, the following error message is thrown : Map has no value 'name'

Is it possible to use a query param with json value with Openapi generator 5.0.0 ? If yes, what's wrong with my config ?

openapi-generator version

5.0.0

OpenAPI declaration file content or url

Generation Details

Steps to reproduce

Related issues/PRs

Suggest a fix

Start by reproducing Java/webclient generation from the supplied Swagger YAML, then trace how the filter query parameter is serialized in the generated code and where the “Map has no value 'name'” error occurs. Done means a JSON-valued string query parameter is accepted and sent correctly, with a regression test covering the example.