java 百度坐标转高德

以下是Java实现百度坐标转高德坐标的代码，其中bd_encrypt将BD-09坐标转换成GCJ-02坐标，gcj_decrypt_exact将GCJ-02坐标转换成WGS-84坐标，wgs84_to_gcj02将WGS-84坐标转换成GCJ-02坐标，gcj02_to_bd09将GCJ-02坐标转换成BD-09坐标。

public class CoordinateTransformUtil {
    private static final double pi = 3.1415926535897932384626;
    private static final double a = 6378245.0;
    private static final double ee = 0.00669342162296594323;

    private static double transformLat(double x, double y) {
        double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y + 0.2 * Math.sqrt(Math.abs(x));
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;
        ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0;
        return ret;
    }

    private static double transformLon(double x, double y) {
        double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1 * Math.sqrt(Math.abs(x));
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;
        ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;
        ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0 * pi)) * 2.0 / 3.0;
        return ret;
    }

    /**
     * BD-09坐标转GCJ-02坐标
     *
     * @param bdLat BD-09坐标纬度
     * @param bdLon BD-09坐标经度
     * @return GCJ-02坐标：[纬度，经度]
     */
    public static double[] bd_encrypt(double bdLat, double bdLon) {
        double x = bdLon - 0.0065;
        double y = bdLat - 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 ggLng = z * Math.cos(theta);
        double ggLat = z * Math.sin(theta);
        return new double[]{ggLat, ggLng};
    }

    /**
     * GCJ-02坐标转WGS-84坐标
     *
     * @param gcjLat GCJ-02坐标纬度
     * @param gcjLon GCJ-02坐标经度
     * @return WGS-84坐标：[纬度，经度]
     */
    public static double[] gcj_decrypt_exact(double gcjLat, double gcjLon) {
        double initDelta = 0.01;
        double threshold = 0.000000001;
        double dLat = initDelta, dLon = initDelta;
        double mLat = gcjLat - dLat, mLon = gcjLon - dLon;
        double pLat = gcjLat + dLat, pLon = gcjLon + dLon;
        double wgsLat, wgsLon, i = 0;
        while (true) {
            wgsLat = (mLat + pLat) / 2;
            wgsLon = (mLon + pLon) / 2;
            double[] tmp = wgs84_to_gcj02(wgsLat, wgsLon);
            dLat = tmp[0] - gcjLat;
            dLon = tmp[1] - gcjLon;
            if ((Math.abs(dLat) < threshold) && (Math.abs(dLon) < threshold))
                break;

            if (dLat > 0) pLat = wgsLat;
            else mLat = wgsLat;
            if (dLon > 0) pLon = wgsLon;
            else mLon = wgsLon;

            if (++i > 10000) break;
        }
        return new double[]{wgsLat, wgsLon};
    }

    /**
     * WGS-84坐标转GCJ-02坐标
     *
     * @param wgLat WGS-84坐标纬度
     * @param wgLon WGS-84坐标经度
     * @return GCJ-02坐标：[纬度，经度]
     */
    public static double[] wgs84_to_gcj02(double wgLat, double wgLon) {
        if (outOfChina(wgLat, wgLon)) {
            return new double[]{wgLat, wgLon};
        }
        double dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
        double dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
        double radLat = wgLat / 180.0 * pi;
        double magic = Math.sin(radLat);
        magic = 1 - ee * magic * magic;
        double sqrtMagic = Math.sqrt(magic);
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);
        dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);
        double mgLat = wgLat + dLat;
        double mgLon = wgLon + dLon;
        return new double[]{mgLat, mgLon};
    }

    /**
     * GCJ-02坐标转BD-09坐标
     *
     * @param gcjLat GCJ-02坐标纬度
     * @param gcjLon GCJ-02坐标经度
     * @return BD-09坐标：[纬度，经度]
     */
    public static double[] gcj02_to_bd09(double gcjLat, double gcjLon) {
        double x = gcjLon, y = gcjLat;
        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 bdLon = z * Math.cos(theta) + 0.0065;
        double bdLat = z * Math.sin(theta) + 0.006;
        return new double[]{bdLat, bdLon};
    }

    /**
     * 判断是否在国内，不在国内不做偏移
     *
     * @param lat 纬度
     * @param lon 经度
     * @return 是否在国内
     */
    public static boolean outOfChina(double lat, double lon) {
        if (lon < 72.004 || lon > 137.8347)
            return true;
        if (lat < 0.8293 || lat > 55.8271)
            return true;
        return false;
    }
}