计算两个经纬度点之间的距离[java]

private final static double PI = 3.14159265358979323; private final static double R = 6371229;   //纬线圈所在的半径长度，单位米  public double getDistance(double longt1, double lat1, double longt2,double lat2) {                 double x, y, distance;          x = (longt2 - longt1) * PI * R* Math.cos(((lat1 + lat2) / 2) * PI / 180) / 180;          y = (lat2 - lat1) * PI * R / 180;          distance = Math.hypot(x, y);          return distance;}