class BannerEntity { String id; String image; int serialNo; int type; String url; BannerEntity({this.image,this.url="http://www.edtyun.com"}); BannerEntity.fromJsonMap(Map map): id = map["id"], image = map["image"], serialNo = map["serialNo"], type = map["type"], url = map["url"]??""; Map toJson() { final Map data = new Map(); data['id'] = id; data['image'] = image; data['serialNo'] = serialNo; data['type'] = type; data['url'] = url; return data; } }