根据经纬度计算两者距离

/**
 * Created with IntelliJ IDEA.
 * User: Java God
 * Date: 2018/3/16 下午2:21
 * Description:
 * 根据两个位置的经纬度，来计算两地的距离（单位为KM）
 * 参数为double类型
 *  long1 位置1经度
 *  lat1  位置1纬度
 *  long2 位置2经度
 *  lat2  位置2纬度
 */
public class Distance {

    private static final double EARTH_RADIUS = 6378.137;

    private static double rad(double d) {
        return d * Math.PI / 180.0;
    }

    public static double GetDistance(double long1, double lat1, double long2, double lat2) {
        double a, b, d, sa2, sb2;
        lat1 = rad(lat1);
        lat2 = rad(lat2);
        a = lat1 - lat2;
        b = rad(long1 - long2);

        sa2 = Math.sin(a / 2.0);
        sb2 = Math.sin(b / 2.0);
        d = 2 * EARTH_RADIUS
                * Math.asin(Math.sqrt(sa2 * sa2 + Math.cos(lat1)
                * Math.cos(lat2) * sb2 * sb2));
        return d;
    }

    public static void main(String[] args) {
        //根据两点间的经纬度计算距离，单位：km
        System.out.println(GetDistance(118.904838, 32.107081, 116.536017, 39.986811));
    }
}