android device ID获取

private static String getGsfAndroidId(Context context) 
    {
        Uri URI = Uri.parse("content://com.google.android.gsf.gservices");
        String ID_KEY = "android_id";
        String params[] = {ID_KEY};
        Cursor c = context.getContentResolver().query(URI, null, null, params, null);
        if (!c.moveToFirst() || c.getColumnCount() < 2)
            return null;
        try 
        {
            return Long.toHexString(Long.parseLong(c.getString(1)));
        } 
        catch (NumberFormatException e) 
        {
            return null;
        }
    }