public synchronized Message recv() throws IOException {
		MsgHead head = new MsgHead();
		head.read(in);//读取消息头
		Message msg = null;
		switch (head.getCommand()) {
		case -2147483647://Bind响应命令
			msg = new BindResp();
			msg.read(in);
			break; 
		case -2147483644:
			msg = new DeliverResp();
			msg.read(in);
			break; 
		case -2147483643:
			msg = new ReportResp();
			msg.read(in);
			break; 
		case -2147483645:
			msg = new SubmitResp();
			msg.read(in);
			break; 
		case -2147483646:
			msg = new UnbindResp();
			msg.read(in);
			break;
		}
		if (msg != null) msg.setHead(head);
		return msg; 
	}