json格式，分为 中国>大区>省>市>区县。。按全国7大区分的。 "id": 1, "pid": 0, "district_code": "", "district_name": "中国", "type": 0, "hierarchy": 0, "chindren": [ { "id": 2, "pid": 1, "district_code": "", "district_name": "东北大区", "type": 0, "hierarchy": 1, "chindre