C#封装百度Web服务API处理包含（Geocoding API，坐标转换API）

1、创建基础参数类

   public static class BaiduConstParams
     {
         public const string PlaceApIv2Search = "http://api.map.baidu.com/place/v2/search";
         public const string PlaceApIv2Detail = "http://api.map.baidu.com/place/v2/detail";
         public const string PlaceApIv2Eventsearch = "http://api.map.baidu.com/place/v2/eventsearch";
         public const string PlaceApIv2Eventdetail = "http://api.map.baidu.com/place/v2/eventdetail";
         public const string GeocodingApIv2 = "http://api.map.baidu.com/geocoder/v2/";
         public const string GeocodingApIv2Reverse = "http://api.map.baidu.com/geocoder/v2/";
         public const string TranslateApi = "http://openapi.baidu.com/public/2.0/bmt/translate";
         public const string GeoconvApi = "http://api.map.baidu.com/geoconv/v1/";
     }

     public static class BaiduErrorMessages
     {
         public const string NotKey = "密钥不存在";
         public const string LackParam = "缺少必要请求参数";
     }

2、定义API错误信息与产品信息

 public enum BaiduLbsType
     {
         PlaceApIv2Search,
         PlaceApIv2Detail,
         PlaceApIv2Eventsearch,
         PlaceApIv2Eventdetail,
         GeocodingApIv2,
         GeocodingApIv2Reverse,
         Translate,
         Geoconv
     }

     public enum Status
     {
         /// <summary>
         /// 正常
         /// </summary>
         Ok = ,
         /// <summary>
         /// 请求参数非法
         /// </summary>
         ParameterInvalid = ,
         /// <summary>
         /// 权限校验失败
         /// </summary>
         VerifyFailure = ,
         /// <summary>
         /// 配额校验失败
         /// </summary>
         QuotaFailure = ,
         /// <summary>
         /// 不存在或者非法
         /// </summary>
         AkFailure = ,
         /// <summary>
         /// Transform 内部错误
         /// </summary>
         InternalError = ,
         /// <summary>
         /// from非法
         /// </summary>
         FromIllegal = ,
         /// <summary>
         /// to非法
         /// </summary>
         ToIllegal = ,
         /// <summary>
         /// coords非法
         /// </summary>
         CoordsIllegal = ,
         /// <summary>
         /// coords个数非法，超过限制
         /// </summary>
         CoordsCountIllegal = 

     }

3、定义API结果返回实体映射类

 public class BaiduGeocodingResults
    {
        /// <summary>
        /// 返回结果状态值， 成功返回0，其他值请查看附录。
        /// </summary>
        [JsonProperty(PropertyName = "status")]
        public Status Status;

        /// <summary>
        /// 返回结果状态值， 成功返回0，其他值请查看附录。
        /// </summary>
        [JsonProperty(PropertyName = "result")]
        public BaiduGeocodingResult Result;
    }

    public class BaiduGeocodingResult
    {
        /// <summary>
        /// 经纬度坐标
        /// </summary>
        [JsonProperty(PropertyName = "location")]
        public BaiduGeocodingLoaction Location;
        /// <summary>
        /// 位置的附加信息，是否精确查找。1为精确查找，0为不精确。
        /// </summary>
        [JsonProperty(PropertyName = "precise")]
        public int Precise;
        /// <summary>
        /// 可信度
        /// </summary>
        [JsonProperty(PropertyName = "confidence")]
        public int Confidence;
        /// <summary>
        /// 地址类型
        /// </summary>
        [JsonProperty(PropertyName = "level")]
        public string Level;

        /// <summary>
        /// 结构化地址信息
        /// </summary>
        [JsonProperty(PropertyName = "formatted_address")]
        public string FormattedAddress;

        /// <summary>
        /// 所在商圈信息，如 "人民大学,中关村,苏州街"
        /// </summary>
        [JsonProperty(PropertyName = "business")]
        public string Business;

        /// <summary>
        /// 具体地址
        /// </summary>
        [JsonProperty(PropertyName = "addressComponent")]
        public BaiduGeocodingAddress AddressComponent;
    }

    public class BaiduGeocodingLoaction
    {
        /// <summary>
        /// 纬度值
        /// </summary>
        [JsonProperty(PropertyName = "lat")]
        public decimal Lat;
        /// <summary>
        /// 经度值
        /// </summary>
        [JsonProperty(PropertyName = "lng")]
        public decimal Lng;
    }

    public class BaiduGeocodingAddress
    {
        /// <summary>
        /// 城市名
        /// </summary>
        [JsonProperty(PropertyName = "city")]
        public string City;
        /// <summary>
        /// 区县名
        /// </summary>
        [JsonProperty(PropertyName = "district")]
        public string District;
        /// <summary>
        /// 省名
        /// </summary>
        [JsonProperty(PropertyName = "province")]
        public string Province;
        /// <summary>
        /// 街道名
        /// </summary>
        [JsonProperty(PropertyName = "street")]
        public string Street;
        /// <summary>
        /// 街道门牌号
        /// </summary>
        [JsonProperty(PropertyName = "street_number")]
        public string StreetNumber;
    }

4、创建API通用处理类

 public class BaiduLbs
     {
         private readonly string _key;

         public static string CurrentRequest = "";

         public BaiduLbs(string key)
         {
             _key = key;
         }

         /// <summary>
         /// 请求
         /// </summary>
         /// <param name="param"></param>
         /// <param name="baiduLbsType"></param>
         /// <param name="encoding"></param>
         /// <param name="action"></param>
         public void Request(string param, BaiduLbsType baiduLbsType, Encoding encoding, Action<string> action)
         {
             WebClient webClient = new WebClient { Encoding = encoding };
             string url = "";
             switch (baiduLbsType)
             {
                 case BaiduLbsType.PlaceApIv2Search:
                     url = string.Format(BaiduConstParams.PlaceApIv2Search + "?{0}", param);
                     break;
                 case BaiduLbsType.PlaceApIv2Detail:
                     url = string.Format(BaiduConstParams.PlaceApIv2Detail + "?{0}", param);
                     break;
                 case BaiduLbsType.PlaceApIv2Eventsearch:
                     url = string.Format(BaiduConstParams.PlaceApIv2Eventsearch + "?{0}", param);
                     break;
                 case BaiduLbsType.PlaceApIv2Eventdetail:
                     url = string.Format(BaiduConstParams.PlaceApIv2Eventdetail + "?{0}", param);
                     break;
                 case BaiduLbsType.GeocodingApIv2:
                 case BaiduLbsType.GeocodingApIv2Reverse:
                     url = string.Format(BaiduConstParams.GeocodingApIv2 + "?{0}", param);
                     break;
                 case BaiduLbsType.Translate:
                     url = string.Format(BaiduConstParams.TranslateApi + "?{0}", param);
                     break;
                 case BaiduLbsType.Geoconv:
                     url = string.Format(BaiduConstParams.GeoconvApi + "?{0}", param);
                     break;

             }
             CurrentRequest = url;
             action(webClient.DownloadString(url));
         }

         /// <summary>
         /// 响应
         /// </summary>
         /// <typeparam name="T"></typeparam>
         /// <param name="param"></param>
         /// <param name="baiduLbsType"></param>
         /// <param name="encoding"></param>
         public T Response<T>(string param, BaiduLbsType baiduLbsType, Encoding encoding)
         {
             T t = default(T);

             Request(param, baiduLbsType, encoding, json =>
                 {
                     if (baiduLbsType == BaiduLbsType.GeocodingApIv2 || baiduLbsType == BaiduLbsType.GeocodingApIv2Reverse)
                     {
                         if (json.Contains("\"result\":[]"))
                         {
                             json = json.Replace("\"result\":[]", "\"result\":{}");
                         }
                     }
                     t = (T)JsonConvert.DeserializeObject(json, typeof(T));
                 });
             return t;
         }

         public BaiduGeocodingResults BaiduGeocoding(string address, string city)
         {
             address = System.Web.HttpUtility.UrlEncode(address);
             city = System.Web.HttpUtility.UrlEncode(city);
             string request = string.Format("address={0}&output=json&ak={1}&city={2}", address, _key, city);
             var result = Response<BaiduGeocodingResults>(request, BaiduLbsType.GeocodingApIv2, Encoding.UTF8);
             if (result.Status == Status.Ok && result.Result.Location == null)
             {
                 request = string.Format("address={0}&output=json&ak={1}&city={2}", city + address, _key, city);
                 return Response<BaiduGeocodingResults>(request, BaiduLbsType.GeocodingApIv2, Encoding.UTF8);
             }
             return result;
         }

         public BaiduGeocodingResults BaiduGeocoding(string longitude, string dimensions, string pois)
         {
             var location = longitude + "," + dimensions;
             string request = string.Format("ak={0}&location={1}&pois={2}", _key, location, pois);
             return Response<BaiduGeocodingResults>(request, BaiduLbsType.GeocodingApIv2, Encoding.UTF8);
         }

         public GeoconvResults BaiduGeoconv(GeoconvParams geoconvParams, ref List<GeoconvPOI> geoconvPois)
         {
             geoconvParams.Ak = _key;
             return Response<GeoconvResults>(geoconvParams.ToString(ref geoconvPois), BaiduLbsType.Geoconv, Encoding.UTF8);
         }

         public GeoconvResults BaiduGeoconv(GeoconvParams geoconvParams, GeoconvPOI geoconvPoi)
         {
             geoconvParams.Ak = _key;
             List<GeoconvPOI> geoconvPois = new List<GeoconvPOI>
                                                {
                                                    geoconvPoi
                                                };
             return Response<GeoconvResults>(geoconvParams.ToString(ref geoconvPois), BaiduLbsType.Geoconv, Encoding.UTF8);
         }
     }