Java下面根据两点经纬度坐标来算距离

public class Test {  private static final double EARTH_RADIUS = 6378137;  private static double rad(double d)     {        return d * Math.PI / 180.0;     }          /** *//**      * 根据两点间经纬度坐标（double值），计算两点间距离，单位为米      * @param lng1      * @param lat1      * @param lng2      * @param lat2      * @return      */     public static double GetDistance(double lng1, double lat1, double lng2, double lat2)   {        double radLat1 = rad(lat1);        double radLat2 = rad(lat2);        double a = radLat1 - radLat2;        double b = rad(lng1) - rad(lng2);        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;        s = Math.round(s * 10000) / 10000;        return s;     }               /**       * @param args      */     public static void main(String[] args)     {     // TODO 自动生成方法存根         double distance = GetDistance(121.491909,31.233234,121.411994,31.206134);         System.out.println("Distance is:"+distance);     }}