选课管理系统(jsp+servlet+java)

package com.course; import java.io.*; import java.sql.*; import javax.servlet.*; import javax.servlet.http.*; public class StudentSvlt extends HttpServlet{ public void doGet(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { //获得学生ID String stu_id =req.getParameter("id"); int success = 0; // 获取请求中的参数 String action = action = req.getParameter("action"); student stu = null; String message=""; //如果请求中包含新建学生参数 if ("new".equalsIgnoreCase(action)) { // 调用新建学生方法 stu = doNew(req,res); // 并将新建学生存储在request上下文中，然后转向getStudent.jsp页面 sendBean(req, res, stu, "/getStudent.jsp"); } // 如果请求中包含修改学生参数 if ("update".equalsIgnoreCase(action)) { try{ // 调用修改学生信息方法 stu = doUpdate(req,res, stu_id); // 并将修改后的学生信息存储在request上下文中，然后转向getStudent.jsp页面 sendBean(req,res,stu,"/getStudent.jsp"); } catch(SQLException e){} } // 如果请求中包含删除学生参数 if ("delete".equalsIgnoreCase(action)) { try{ //调用删除学生方法 success = doDelete(stu_id); } catch(SQLException e){} if (success != 1) { doError(req, res, "StudentSvlt: Delete unsuccessful. Rows affected: " + success); } else { res.sendRedirect("http://localhost:8080/test/getStudent.jsp"); } } } //新建学生方法定义 public student doNew(HttpServletRequest req,HttpServletResponse res ) throws ServletException,IOException{ student stu= new student(); String stu_id=req.getParameter("id"); String name=new String(req.getParameter("name").getBytes("ISO8859_1")); String password= req.getParameter("password"); String dep=new String (req.getParameter("dep").getBytes("ISO8859_1")); String sex = new String(req.getParameter("sex").getBytes("ISO8859_1")); String jiguan = new String(req.getParameter("jiguan").getBytes("ISO8859_1")); if(isTrue(req,res,stu_id,name,password) && hasLogin(req,res,stu_id)){ stu.setId(stu_id); stu.setName(name); stu.setPassword(password); stu.setDep(dep); stu.setSex(sex); stu.setJiguan(jiguan); stu.addStudent(); } return stu; } //更新学生信息方法 public student doUpdate(HttpServletRequest req,HttpServletResponse res , String id) throws ServletException,IOException,SQLException { student stu = new student(); String name=new String(req.getParameter("name").getBytes("ISO8859_1")); String password = req.getParameter("password"); String dep = new String(req.getParameter("dep").getBytes("ISO8859_1")); String sex = new String(req.getParameter("sex").getBytes("ISO8859_1")); String jiguan = new String(req.getParameter("jiguan").getBytes("ISO8859_1")); if(isTrue(req,res,id,name,password)){ stu.setId(id); stu.setName(name); stu.setPassword(password); stu.setDep(dep); stu.setSex(sex); stu.setJiguan(jiguan); stu.updateStudent();} return stu; } //删除学生方法 public int doDelete(String id) throws SQLException { int num=0; student stu=new student(); num=stu.deleteStudent(id); return num; } //保存学生信息的JavaBean到request上下文中 public void sendBean(HttpServletRequest req, HttpServletResponse res, student stu, String target) throws ServletException, IOException { req.setAttribute("stu", stu); RequestDispatcher rd = getServletContext().getRequestDispatcher(target); rd.forward(req, res); } //错误处理方法 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); } //判断学生是否被注册过 public boolean hasLogin(HttpServletRequest req, HttpServletResponse res,String id) throws ServletException, IOException{ boolean f=true; String message="对不起，该学生号已经被注册过了!"; student stu= new student(); f= stu.hasLogin(id); if(f==false){ doError(req,res,message); } return f; } //判断学生注册是否成功 public boolean isTrue(HttpServletRequest req, HttpServletResponse res, String id,String name,String password) throws ServletException, IOException { boolean f=true; String message =""; if(id==null || id.equals("")) { f=false; message="错误，学生号不能为空！"; doError(req,res,message); } if(name==null || name.equals("")) { f=false; message="学生姓名不能为空，请重新填写！"; doError(req,res,message); } if(password==null || password.equals("")) { f=false; message="密码不能为空，请重新填写！"; doError(req,res,message); } return f; } //响应post请求 public void doPost(HttpServletRequest req, HttpServletResponse res) throws ServletException, IOException { doGet(req, res); } }