全国省市区json数据，扁平树结构。通过districtCode和parentCode将父子级关系串联起来。 示例片段： { "id": "297", "districtCode": "297", "districtName": "武汉市", "parentCode": "24", "districtType": "3", "postCode": "", "zipCode": "", "isValid": "1", "createdBy": "1", "createdTime": "1", "updatedBy": "1", "updatedTime": "1", "deleted": "1" }, { "id": "298", "districtCode": "298", "districtName": "宜昌市", "parentCode": "24", "districtType": "3", "postCode": "", "zipCode": "", "isValid": "1", "createdBy": "1", "createdTime": "1", "updatedBy": "1", "updatedTime": "1", "deleted": "1" }, ......