private Object strangeCodeForJackson(Object obj) {
        if (obj != null) {
            String className = obj.getClass().getName();
            if ("com.fasterxml.jackson.databind.node.ObjectNode".equals(className)) {
                return obj.toString();
            }
        }
        return obj;
    }
Add serialize filter.

@param filter the filter
@see FastJsonConfig#setSerializeFilters(SerializeFilter...)
@deprecated
src/main/java/com/alibaba/fastjson/support/spring/FastJsonHttpMessageConverter.java