106 lines
3.0 KiB
C#
106 lines
3.0 KiB
C#
using Microsoft.CodeAnalysis.CSharp.Syntax;
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using System;
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using System.Collections.Generic;
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using System.Globalization;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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namespace Admin.NET.Core.Service
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{
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/// <summary>
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/// 根据经纬度获取城市
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/// </summary>
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[ApiDescriptionSettings(Order = 101)]
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[AllowAnonymous]
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public class LocationService : IDynamicApiController, ITransient
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{
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private readonly SqlSugarRepository<SysRegion> _region;
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public LocationService(SqlSugarRepository<SysRegion> reginService)
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{
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this._region = reginService;
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}
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/// <summary>
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/// Haversine公式计算距离
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/// </summary>
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/// <param name="lat1"></param>
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/// <param name="lon1"></param>
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/// <param name="lat2"></param>
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/// <param name="lon2"></param>
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/// <returns></returns>
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private double CalculateDistance(double lat1, double lon1, double lat2, double lon2)
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{
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const double R = 6371; // 地球半径，单位：千米
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double dLat = (lat2 - lat1) * (Math.PI / 180);
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double dLon = (lon2 - lon1) * (Math.PI / 180);
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double a = Math.Sin(dLat / 2) * Math.Sin(dLat / 2) +
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Math.Cos(lat1 * (Math.PI / 180)) * Math.Cos(lat2 * (Math.PI / 180)) *
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Math.Sin(dLon / 2) * Math.Sin(dLon / 2);
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double c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));
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return R * c;
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}
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// 根据传入的经纬度查找最近的城市
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[NonAction]
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private CityData FindNearestCity(List<CityData> _cityDataList, double targetLatitude, double targetLongitude)
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{
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if (_cityDataList.Count == 0)
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{
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return new CityData() { };
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}
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double minDistance = double.MaxValue;
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var nearestCity = new CityData();
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foreach (var cityData in _cityDataList)
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{
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double distance = CalculateDistance(targetLatitude, targetLongitude, cityData.Latitude, cityData.Longitude);
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if (distance < minDistance)
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{
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minDistance = distance;
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nearestCity = cityData;
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}
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}
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return nearestCity;
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}
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/// <summary>
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/// 根据经纬度获取城市
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/// </summary>
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/// <param name="lng"></param>
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/// <param name="lat"></param>
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/// <returns></returns>
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[HttpGet("getcity")]
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public dynamic GetCity([FromQuery] double lng, [FromQuery] double lat)
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{
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var citylist = this._region.AsQueryable().Where(e => e.Level == 1).ToList();
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List<CityData> cities = citylist.Select(s => new CityData()
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{
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Latitude = s.Lat,
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Longitude = s.Lng,
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CityName = s.Name,
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LocationCode = s.Code
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}).ToList();
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return FindNearestCity(cities, lat, lng);
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}
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}
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}
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