loginservlet.java

本源码主要从数据库的开发过程出发

/*
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 * and open the template in the editor.
 */
package Source;

import java.io.*;
import java.sql.*;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.servlet.*;
import javax.servlet.http.*;

public class LoginServlet extends HttpServlet {

    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException, SQLException {
        HttpSession session = request.getSession();
        
        String userID = "";
        String userName = "";
        String password="";
        String title = "";
        int position = 0;
        String sql = "";
        JDBCBean jdbcbean = new JDBCBean();
        ResultSet rs = null;

        userID = request.getParameter("userid");
        password = request.getParameter("password");
        position = Integer.parseInt(request.getParameter("position"));

        switch (position) {
            case 1:
                title = "student";
                sql = "select * from student where userId='" + userID + "'";
                break;
            case 2:
                title = "teacher";
                sql = "select * from teacher where userId='" + userID + "'";
                break;
            case 3:
                title = "admin";
                sql = "select * from admin where userId=\"" + userID + "\"";
                break;
        }

        rs=jdbcbean.executeQuery(sql);
        if (rs.next()) {
            if (password != null && password.equals(rs.getString("password"))) {
                userInf userinf = new userInf(userID, rs.getString("userName"), password, title, position, true);
                session.setAttribute("userinf", userinf);
                response.sendRedirect(title+".jsp");
            } else {
                position = 0;
                title = "";
                response.sendRedirect("Login.jsp");
            }
        } else {
            response.sendRedirect("Login.jsp");
        }
        rs.close();
        jdbcbean.close();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        try {
            processRequest(request, response);
        } catch (SQLException ex) {
            ex.printStackTrace();
        }
    }

    /** 
     * Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        try {
            processRequest(request, response);
        } catch (SQLException ex) {
            Logger.getLogger(LoginServlet.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    /** 
     * Returns a short description of the servlet.
     */
    public String getServletInfo() {
        return "Short description";
    }
    // </editor-fold>
}