往服务器连续写7个字节的数据作为命令，但是javabyte类型的范围为-128-127。这样要转换

bos.write(60);Log.i("CommandService","send db playerId:"+PreviewActivity.playerId);    byte[] b = new byte[4];for(int i = 0;i < 4;i++){ b[i] = (byte)(PreviewActivity.playerId >> (24 - i * 8));    }for(int i=3;i>=0;i--){bos.write(b[i]);}bos.write(50);bos.write(reqCode);bos.flush();