jsp学生管理

import java.io.*; import java.sql.*; import javax.servlet.*; import javax.servlet.http.*; public class CourseSvlt extends HttpServlet{ public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { String cour_id =req.getParameter("id"); int success = 0; String action = action = req.getParameter("action"); course cour = null; String message=""; if ("new".equalsIgnoreCase(action)) { cour = doNew(req,res); sendBean(req, res, cour, "/getcourse.jsp"); } if ("update".equalsIgnoreCase(action)) { try{ cour = doUpdate(req,res, cour_id); sendBean(req,res,cour,"/getcourse.jsp"); } catch(SQLException e){} } if ("delete".equalsIgnoreCase(action)) { try{ success = doDelete(cour_id); } catch(SQLException e){} if (success != 1) { doError(req, res, "CourseSvlt: Delete unsuccessful. Rows affected: " + success); } else { res.sendRedirect("http://localhost:8080/test/getcourse.jsp"); }} } public course doNew(HttpServletRequest req,HttpServletResponse res ) throws ServletException,IOException{ course cour= new course(); String cour_id=req.getParameter("id"); int mark; String name=new String(req.getParameter("name").getBytes("ISO8859_1")); try{ mark= Integer.parseInt(req.getParameter("mark")); }catch(NumberFormatException e){mark=0;} String dep=new String (req.getParameter("dep").getBytes("ISO8859_1")); String prepare =req.getParameter("prepare"); if(isTrue(req,res,cour_id,name) && hasLogin(req,res,cour_id) && isCompare(prepare,dep,req,res)){ cour.setId(cour_id); cour.setName(name); cour.setDep(dep); cour.setPrepare(prepare); cour.setMark(mark); cour.addCourse(); } return cour; } public boolean isCompare(String prepare,String dep, HttpServletRequest req,HttpServletResponse res)throws ServletException,IOException{ boolean f=true; String tempDep=null; String message=null; course cour= new course(); if( !prepare.equalsIgnoreCase("0") ){ tempDep=cour.getPrepareDep(prepare) ; if(tempDep.equals("public")) return true; if(dep.equalsIgnoreCase(tempDep)) f=true; else { f=false; message="错误，课程所在系与预修课所在系不一致！"; doError(req,res,message); }} return f; } public course doUpdate(HttpServletRequest req,HttpServletResponse res , String id) throws ServletException,IOException,SQLException { course cour = new course(); String name=new String(req.getParameter("name").getBytes("ISO8859_1")); int mark = Integer.parseInt(req.getParameter("mark")); String dep = req.getParameter("dep"); String prepare = req.getParameter("prepare"); if(isTrue(req,res,id,name) && isCompare(prepare,dep,req,res)){ cour.setName(name); cour.setMark(mark); cour.setDep(dep); cour.setPrepare(prepare); cour.updateCourse(id);} return cour; } public int doDelete(String id) throws SQLException { int num=0; course cour=new course(); num=cour.deleteCourse(id); return num; } public void sendBean(HttpServletRequest req, HttpServletResponse res, course cour, String target) throws ServletException, IOException { req.setAttribute("cour", cour); 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 hasLogin(HttpServletRequest req, HttpServletResponse res,String id) throws ServletException, IOException{ boolean f=true; String message="对不起，该课程号已经被注册过了!"; course cour= new course(); f= cour.hasLogin(id); if(f==false){ doError(req,res,message); } return f; } public boolean isTrue(HttpServletRequest req, HttpServletResponse res, String id,String name) throws ServletException, IOException { boolean f=true; String message =""; if(id==null || id.equals("")) { f=false; message="错误，课程号不能为空！"; doError(req,res,message); } if(name==null || name.equals("")) { f=false; message="课程名不能为空，请重新填写！"; doError(req,res,message); } return f; } public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { doGet(req, res); } }