private static double PI = 3.14159265358979324;
public static double[] gcj02ToWgs(double lng, double lat) {
    double a = 6378245.0; //  a: 卫星椭球坐标投影到平面地图坐标系的投影因子。
    double ee = 0.00669342162296594323; //  ee: 椭球的偏心率。
    double lat1 = +lat;
    double lng1 = +lng;
    double dlat = transformLat(lng1 - 105.0, lat1 - 35.0);
    double dlng = transformLon(lng1 - 105.0, lat1 - 35.0);
    double radlat = lat1 / 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);
    dlng = (dlng * 180.0) / (a / sqrtmagic * Math.cos(radlat) * PI);
    double mglat = lat1 + dlat;
    double mglng = lng1 + dlng;
    double [] latlng = new double[2];
    latlng[0] = lng1 * 2 - mglng;
    latlng[1] = lat1 * 2 - mglat;
    return latlng;
}
public 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;
}
public 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;
}
public static void main(String[] args){
    Double lng = 116.315033;
    Double lat = 39.945199;
    double[] x = gcj02ToWgs(lng, lat);
    System.out.println(x[0]);
    System.out.println(x[1]);
}