GCJ02转WGS84

GCJ02转WGS84，加密代码和解密思路来自https://blog.51cto.com/zhangchanggong/1547863

和原文不同的地方主要是优化了坐标是否在中国的判断，判断方法的代码来自amap，请勿用于商业用途。

 解密的精度依赖于加密的精度，由于加密的精度不是特别高，所以解密的精度设置到0.0000001足够了。解密过程：

public class CoordinateConverter {

    public static double[] WGS84ToGCJ02(double lon, double lat) {
        double[] transform = EvilTransform.transform(lat, lon);
        return new double[]{transform[1], transform[0]};
    }

    public static double[] GCJ02ToWGS84(double lon, double lat) {
        double d = 0.0000001;
        double longitude = lon;
        double latitude = lat;
        double[] transform;

        do {
            transform = EvilTransform.transform(latitude, longitude);
            latitude += lat - transform[0];
            longitude += lon - transform[1];
        } while (lon - transform[1] > d || lat - transform[0] > d);

        return new double[]{longitude, latitude};
    }
}

加密代码：

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

    // World Geodetic System ==> Mars Geodetic System
    public static double[] transform(double wgLat, double wgLon) {
        double mgLat = 0;
        double mgLon = 0;
        if (outOfChina(wgLat, wgLon)) {
            mgLat = wgLat;
            mgLon = wgLon;
        } else {
            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);
            mgLat = wgLat + dLat;
            mgLon = wgLon + dLon;
        }
        double[] point = {mgLat, mgLon};
        return point;
    }

    private static boolean outOfChina(double lat, double lon) {
        return !inChina(lat, lon);
    }

    private static boolean inChina(double lat, double lon) {
        try {
            int var4 = (int) ((lon - 73.0D) / 0.5D);
            int var5 = (int) ((lat - 3.5D) / 0.5D);
            if (var5 >= 0 && var5 < 101 && var4 >= 0 && var4 < 124) {
                int var6 = 124 * var5 + var4;
                char var7 = "0000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000110000000101100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001110101011110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011011111111100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011110111111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000100011011110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111111111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111111110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001101011100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111001110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011000000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000101001110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011110011000100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000110000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111100011100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111111001100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000111100000000011100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011110000000000001011111010000001100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011111000000000111111111111111100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000011111111100000011111111111111111000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111110111111111111111111111110000000000000000000000000000000000000000000000000000000000000000000000000000000000000001111111111111111111111111111111111111100000000000000000000000000000000000000000000000000000000000000000000000000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                return var7 == '1';
            } else {
                return false;
            }
        } catch (Throwable var8) {
            var8.printStackTrace();
            return true;
        }
    }

    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;
    }
}

这里只有WGS84转GCJ02的加密方法，所以只有GCJ02转WGS84的方法。如果有WGS84转BD09的加密方法，按上面的思路应该也可以把BD09解密成WGS84。