记录 两对经纬度计算距离

private static final  double EARTH_RADIUS = 6378137;//赤道半径
private static double rad(double d){
    return d * Math.PI / 180.0;
}
public static double GetDistance(double lon1,double lat1,double lon2, double lat2) {
    double radLat1 = rad(lat1);
    double radLat2 = rad(lat2);
    double a = radLat1 - radLat2;
    double b = rad(lon1) - rad(lon2);
    double s = 2 *Math.asin(Math.sqrt(Math.pow(Math.sin(a/2),2)+Math.cos(radLat1)*Math.cos(radLat2)*Math.pow(Math.sin(b/2),2))); 
    s = s * EARTH_RADIUS;    
   return s;//单位米
}