login_confirm.java

一个学生课绩管理系统

package control;

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

public class login_confirm extends HttpServlet {

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

		String message = null;
		String id = null;
		id = req.getParameter("id");
		HttpSession session = req.getSession(true);
		session.setAttribute("id", String.valueOf(id));
		String password = null;
		password = req.getParameter("password");

		String kind = null;
		kind = req.getParameter("kind");
		String temp = getPassword(req, res, id, kind);
		if (password.equals(temp))
			goo(req, res, kind);
		else {
			message = "用户名或密码有误！";
			doError(req, res, message);
		}
	}

	public void goo(HttpServletRequest req, HttpServletResponse res, String kind)
			throws ServletException, IOException {
		if (kind.equals("student")) {
			RequestDispatcher rd = getServletContext().getRequestDispatcher(
					"/student.jsp");
			rd.forward(req, res);
		}
		if (kind.equals("teacher")) {
			RequestDispatcher rd = getServletContext().getRequestDispatcher(
					"/teacher.jsp");
			rd.forward(req, res);
		}
		if (kind.equals("admin")) {
			RequestDispatcher rd = getServletContext().getRequestDispatcher(
					"/admin.jsp");
			rd.forward(req, res);
		}
	}

	public String getPassword(HttpServletRequest req, HttpServletResponse res,
			String id, String kind) throws ServletException, IOException {
		sqlBean db = new sqlBean();
		String pw = "";
		String sql = "select password from " + kind + " where id='" + id + "'";
		try {
			ResultSet rs = db.executeQuery(sql);
			if (rs.next()) {
				pw = rs.getString("password");
			}
		} catch (Exception e) {
			System.out.print(e.toString());
		}
		return pw;
	}

	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 void doGet(HttpServletRequest req, HttpServletResponse res)
			throws ServletException, IOException {
		String action = action = req.getParameter("action");
		if ("logout".equalsIgnoreCase(action)) {
			HttpSession session = req.getSession(true);
			session.invalidate();
			RequestDispatcher rd = getServletContext().getRequestDispatcher(
					"/login.jsp");
			rd.forward(req, res);
		}
	}

}