Java中经纬度计算两点距离与区域校验的五种方法

在Java中，根据经纬度计算两点之间的距离有多种方法。以下为您推荐五种常见的方法：

1. 使用Haversine公式：Haversine公式是一个常用的计算两点之间球面距离的公式。它基于地球的近似椭球形状，适用于大多数情况。以下是一个使用Haversine公式的示例：

   public static double calculateDistance(double lat1, double lon1, double lat2, double lon2) {
   double dLat = Math.toRadians(lat2 - lat1);
   double dLon = Math.toRadians(lon2 - lon1);
   lat1 = Math.toRadians(lat1);
   lat2 = Math.toRadians(lat2);
   double a = Math.sin(dLat / 2) * Math.sin(dLat / 2) +
   Math.cos(lat1) * Math.cos(lat2) *
   Math.sin(dLon / 2) * Math.sin(dLon / 2);
   double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
   double distance = EARTH_RADIUS * c; // EARTH_RADIUS is the Earth radius in kilometers (6371km by default)
   return distance;
   }

2. 使用Vincenty’s formulae：Vincenty’s formulae是一种更精确的计算两点之间距离的方法，适用于需要更高精度的应用。以下是一个使用Vincenty’s formulae的示例：
   ```java
   public static double calculateDistanceVincenty(double lat1, double lon1, double lat2, double lon2) {
   final int EARTH_RADIUS = 6371; // Earth radius in kilometers (by default)
   double a = 6086980; // major axis of Earth ellipsoid (in meters)
   double b = 6356300; // minor axis of Earth ellipsoid (in meters)
   double f = 1 / 298.257223563; // flattening of Earth ellipsoid
   double L = Math.toRadians(lon2 - lon1);
   double U1 = Math.atan((1 - f) Math.tan(Math.toRadians(lat1)));
   double U2 = Math.atan((1 - f) Math.tan(Math.toRadians(lat2)));
   double sinU1 = Math.sin(U1);
   double cosU1 = Math.cos(U1);
   double sinU2 = Math.sin(U2);
   double cosU2 = Math.cos(U2);
   double lambda = L;
   double lambdaP = 2 Math.PI;
   double sinSigma = 0;
   double cosSigma = 0;
   double sigma = 0;
   double cosSqAlpha = 0;
   double cos2SigmaM = 0;
   double C = f / 16384 100000; // fictitious constant (arc seconds)
   int iterLimit = 100; // maximum number of iterations for Vincenty’s formulae
   while (Math.abs(lambda - lambdaP) > 1e-12 && —iterLimit > 0) {
   double sinLambda = Math.sin(lambda);
   double cosLambda = Math.cos(lambda);
   sinSigma = Math.sqrt((cosU2 sinLambda) (cosU2 sinLambda) +
   (cosU1 sinU2 - sinU1 cosU2 cosLambda) (cosU1 sinU2 - sinU1 cosU2 cosLambda));
   if (sinSigma == 0) return 0; // co-incident points (infinity distance)
   cosSigma = sinU1 sinU2 + cosU1 cosU2 * cosLambda;
   sigma = Math.atan2(sinSigma, cosSigma); // calculate the arc length [rad] between two