@Override
    protected void setResponseContentType(HttpServletRequest request, HttpServletResponse response) {
        if (getJsonpParameterValue(request) != null) {
            response.setContentType(DEFAULT_JSONP_CONTENT_TYPE);
        } else {
            super.setResponseContentType(request, response);
        }
    }
Filters out undesired attributes from the given model. The return value
can be either another {@link Map}, or a single value object.
<p>
Default implementation removes {@link BindingResult} instances and
entries not included in the {@link #setRenderedAttributes(Set)
renderedAttributes} property.

@param model the model, as passed on to {@link #renderMergedOutputModel}
@return the object to be rendered
src/main/java/com/alibaba/fastjson/support/spring/FastJsonJsonView.java