protected boolean isValidJsonpQueryParam(String value) {
        return CALLBACK_PARAM_PATTERN.matcher(value).matches();
    }
Validate the jsonp query parameter value. The default implementation
returns true if it consists of digits, letters, or "_" and ".".
Invalid parameter values are ignored.

@param value the query param value, never {@code null}
src/main/java/com/alibaba/fastjson/support/spring/FastJsonpResponseBodyAdvice.java