public void beforeBodyWriteInternal(MappingFastJsonValue bodyContainer, MediaType contentType,
                                        MethodParameter returnType, ServerHttpRequest request, ServerHttpResponse response) {
        HttpServletRequest servletRequest = ((ServletServerHttpRequest) request).getServletRequest();
        for (String name : this.jsonpQueryParamNames) {
            String value = servletRequest.getParameter(name);
            if (value != null) {
                if (!isValidJsonpQueryParam(value)) {
                    continue;
                }
                // MediaType contentTypeToUse = getContentType(contentType, request, response);
                // response.getHeaders().setContentType(contentTypeToUse);
                bodyContainer.setJsonpFunction(value);
                break;
            }
        }
    }
Invoked only if the converter type is {@code FastJsonpHttpMessageConverter4}.
src/main/java/com/alibaba/fastjson/support/spring/FastJsonpResponseBodyAdvice.java