public Object showInfoTableHead(String listName) {
		String line = null;
		String[] head = null;
		if (listName.equals("user_list")) {
			listName = "login_list";
		}
		if (!(listName.equals("student_list") || listName.equals("login_list") || listName
				.equals("log_list"))) {
			listName = "teacher_list";
		}
		String cmd = "show；" + listName + "_head";
		try {
			NetService client = initNetService();
			client.sendCommand(cmd);
			line = client.receiveFeedback();
			head = line.split("；");
		} catch (Exception e) {
			e.printStackTrace();
			return Feedback.INTERNET_ERROR;
		}
		return head;
	}