JAVA 计算两个经纬度间的距离

有一个需求。需要根据当前地址，搜索周围的小区

这里是 一个计算两点经纬度距离的方法

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

	public 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;
	}