classsvlt.java

一个学生课绩管理系统

package control;

import java.io.*;
import java.sql.*;
import javax.servlet.*;
import javax.servlet.http.*;

import database.classp;

public class ClassSvlt extends HttpServlet {

	public void doGet(HttpServletRequest req, HttpServletResponse res)
			throws ServletException, IOException {

		String class_id = req.getParameter("id");
		int success = 0;
		String action = action = req.getParameter("action");
		classp cla = null;
		String message = "";

		if ("new".equalsIgnoreCase(action)) {
			cla = doNew(req, res);

			sendBean(req, res, cla, "/getClass.jsp");
		}

		if ("update".equalsIgnoreCase(action)) {
			try {
				cla = doUpdate(req, res, class_id);
				sendBean(req, res, cla, "/getClass.jsp");
			} catch (SQLException e) {
			}
		}

		if ("delete".equalsIgnoreCase(action)) {
			try {
				success = doDelete(class_id);
			} catch (SQLException e) {
			}
			if (success != 1) {
				doError(req, res,
						"ClassSvlt: Delete unsuccessful. Rows affected: "
								+ success);
			} else {
				res.sendRedirect("http://localhost:8080/test/getClass.jsp");
			}
		}

	}

	public classp doNew(HttpServletRequest req, HttpServletResponse res)
			throws ServletException, IOException {
		classp cla = new classp();
		String class_id = req.getParameter("id");
		String tea_id = req.getParameter("tea_id");
		String cour_id = req.getParameter("cour_id");
		String room_id = req.getParameter("room_id");
		String cour_time = req.getParameter("cour_time");

		if (isTrue(req, res, class_id)
				&& hasMoreclass(tea_id, cour_time, req, res)) {
			cla.setId(class_id);
			cla.setTea_id(tea_id);
			cla.setCour_id(cour_id);
			cla.setRoom_id(room_id);
			cla.setCour_time(cour_time);
			cla.addClass();
		}
		return cla;

	}

	public boolean hasMoreclass(String tea_id, String cour_time,
			HttpServletRequest req, HttpServletResponse res)
			throws ServletException, IOException {
		boolean f = true;
		String temp = "";
		String message = "";
		classp cla = new classp();
		temp = cla.hasMoreclass(tea_id, cour_time);
		if (temp == "no")
			f = true;
		else {
			f = false;
			message = "对不起，该教师(" + tea_id + ")在" + cour_time + "时间已经安排有课"
					+ temp + "";
			doError(req, res, message);
		}
		return f;

	}

	public boolean hasChange(String tea_id, String cour_time,
			HttpServletRequest req, HttpServletResponse res)
			throws ServletException, IOException {
		boolean f = false;
		String tea_id0 = req.getParameter("tea_id0");
		String cour_time0 = req.getParameter("cour_time0");
		if (!tea_id.equals(tea_id0) || !cour_time.equals(cour_time0))
			f = true;
		return f;
	}

	public classp doUpdate(HttpServletRequest req, HttpServletResponse res,
			String id) throws ServletException, IOException, SQLException {
		classp cla = new classp();
		String tea_id = req.getParameter("tea_id");
		String cour_id = req.getParameter("cour_id");
		String room_id = req.getParameter("room_id");
		String cour_time = req.getParameter("cour_time");
		if (hasChange(tea_id, cour_time, req, res)) {
			if (hasMoreclass(tea_id, cour_time, req, res)) {
				cla.updateClass(id, tea_id, cour_id, room_id, cour_time);
			}
		} else {
			cla.updateClass(id, cour_id, room_id);
		}
		return cla;
	}

	public int doDelete(String id) throws SQLException {
		int num = 0;
		classp cla = new classp();
		num = cla.deleteClass(id);
		return num;
	}

	public void sendBean(HttpServletRequest req, HttpServletResponse res,
			classp cla, String target) throws ServletException, IOException {
		req.setAttribute("cla", cla);
		RequestDispatcher rd = getServletContext().getRequestDispatcher(target);
		rd.forward(req, res);
	}

	public void doError(HttpServletRequest req, HttpServletResponse res,
			String str) throws ServletException, IOException {

		req.setAttribute("problem", str);
		RequestDispatcher rd = getServletContext().getRequestDispatcher(
				"/errorpage.jsp");
		rd.forward(req, res);
	}

	public boolean isTrue(HttpServletRequest req, HttpServletResponse res,
			String id) throws ServletException, IOException {
		classp cla = new classp();
		boolean f = true;
		String message = "";
		if (id == null || id.equals("")) {
			f = false;
			message = "错误，班级号不能为空！";
			doError(req, res, message);
		}
		if (cla.hasLogin(id)) {
			f = false;
			message = "对不起，班级(" + id + ")已经注册了！";
			doError(req, res, message);
		}
		return f;

	}

	public void doPost(HttpServletRequest req, HttpServletResponse res)
			throws ServletException, IOException {

		doGet(req, res);

	}

}