public void setContext(SerialContext parent, Object object, Object fieldName, int features, int fieldFeatures) {
        if (out.disableCircularReferenceDetect) {
            return;
        }

        this.context = new SerialContext(parent, object, fieldName, features, fieldFeatures);
        if (references == null) {
            references = new IdentityHashMap<Object, SerialContext>();
        }
        this.references.put(object, context);
    }
Set global date format pattern in FastJsonConfig

@param dateFormatPattern global date format pattern
src/main/java/com/alibaba/fastjson/serializer/JSONSerializer.java