下面的消息返回要9秒，是什么原因？

StringBuilder url = new StringBuilder();

url.append(“https://api.weixin.qq.com/sns/jscode2session?”);

url.append(String.format(“appid=%s”, g_regAppId));

url.append(String.format("&secret=%s", g_regAppSecret));

url.append(String.format("&js_code=%s", code));

url.append("&grant_type=authorization_code");

MsgSender sender = new MsgSender();

String res = sender.sendMsgByUrl(url.toString(), “”, 3000);