public class GCJ02_BD09 {

	public static double pi = 3.141592653589793 * 3000.0 / 180.0;

	public static void main(String[] args) {

		// GCJ02 ——> BD09
		gcj02_To_Bd09(116.422954, 40.010749).print();

		// BD09 ——> GCJ02
		bd09_To_Gcj02(121.481085, 31.236173).print();

	}

	/**
	 * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法 将 GCJ-02 坐标转换成 BD-09 坐标
	 * 
	 * @param gg_lat
	 * @param gg_lon
	 * @return
	 */
	public static Gps gcj02_To_Bd09(double gg_lon, double gg_lat) {
		double x = gg_lon, y = gg_lat;
		double z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * pi);
		double theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * pi);
		double bd_lon = z * Math.cos(theta) + 0.0065;
		double bd_lat = z * Math.sin(theta) + 0.006;
		return new Gps(bd_lon, bd_lat);
	}

	/**
	 * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法   将 BD-09 坐标转换成GCJ-02 坐标 
	 * 
	 * @param bd_lon
	 * @param bd_lat
	 * @return
	 */
	public static Gps bd09_To_Gcj02(double bd_lon, double bd_lat) {
		double x = bd_lon - 0.0065, y = bd_lat - 0.006;
		double z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * pi);
		double theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * pi);
		double gg_lon = z * Math.cos(theta);
		double gg_lat = z * Math.sin(theta);
		return new Gps(gg_lon, gg_lat);
	}

	//Gps类
	public static class Gps {

		public double lat;
		public double lon;

		public Gps(double lon, double lat) {
			this.lat = lat;
			this.lon = lon;
		}

		public void print() {
			System.out.println(this.lon + "," + this.lat);
		}
	}

}