altergradeservlet.java

本源码主要从数据库的开发过程出发

/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package Source;

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

/**
 *
 * @author Administrator
 */
public class AlterGradeServlet extends HttpServlet {
   
    /** 
    * Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
    * @param request servlet request
    * @param response servlet response
    */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        HttpSession session = request.getSession();
        userInf userinf = (userInf) session.getAttribute("userinf");
        JDBCBean jdbcBean=(JDBCBean)session.getAttribute("jdbcBean");
        ResultSet rs=null;
        String CNo=request.getParameter("CNo");
        String SNo=request.getParameter("SNo");
        String grade=request.getParameter("grade");
        if(SNo!=null&&!SNo.equals("")){
            try {
                rs=jdbcBean.executeQuery("select * from student where userId='"+SNo+"'");
                if(rs.next()){
                    jdbcBean.executeUpdate("update grade set grade='"+grade+"' where CNo='"+CNo+"' and SNo='"+SNo+"'");
                }
                rs.close();
                jdbcBean.close();
            } catch (SQLException ex) {
                ex.printStackTrace();
            }
        }
    } 

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
    /** 
    * Handles the HTTP <code>GET</code> method.
    * @param request servlet request
    * @param response servlet response
    */
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    } 

    /** 
    * 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 {
        processRequest(request, response);
    }

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