简单的选课系统

package Servlet; import java.io.IOException; import java.io.PrintWriter; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Date; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import Entity.Course; import Entity.KeBiao; import Entity.Student; import MyDao.DBConnection; /** * Servlet implementation class LoginServlet */ public class LoginServlet extends HttpServlet { private static final long serialVersionUID = 1L; private static int flag; private static int index; public static int getIndex() { return index; } public static void setIndex(int index) { LoginServlet.index = index; } public int getFlag() { return flag; } public void setFlag(int flag) { this.flag = flag; } static ArrayList<Integer> la = new ArrayList<Integer>(); protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doPost(request, response); } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("utf-8"); la.add(0);la.add(1);la.add(2);la.add(3);la.add(4);la.add(5);la.add(6);la.add(7);la.add(8);la.add(9); String sname = request.getParameter("pram"); String stu_id = request.getParameter("stu_id"); DBConnection dbConnection = new DBConnection(); Statement statement = dbConnection.getStatement(); String sql=null; ArrayList<Student> ls = new ArrayList<Student>(); ArrayList<Course> ls2 = new ArrayList<Course>(); ArrayList<KeBiao> ls3 = new ArrayList<KeBiao>(); if(sname !=null&&sname.equals("student")){ setIndex(1); setFlag(0); sql = "select * from student"; ResultSet executeQuery; try { executeQuery = statement.executeQuery(sql); while (executeQuery.next()) { String id = executeQuery.getString("id"); String name = executeQuery.getString("name"); int courseNum = 0; Statement statment2 = dbConnection.getStatement(); String sql2 = "select count(*) from select_course where stu_id = '"+id+"'"; ResultSet executeQuery2 = statment2.executeQuery(sql2); if(executeQuery2.next()){ courseNum = executeQuery2.getInt(1); } System.out.println("course_num的值为:" + courseNum); String sql3="update student set course_num = "+courseNum+" where id = "+id+""; statment2.executeUpdate(sql3); Student Student = new Student(); Student.setId(id); Student.setName(name); Student.setCourseNum(courseNum); ls.add(Student); request.getSession().setAttribute("ls", ls); } request.getRequestDispatcher("WEB-INF/student_select.jsp").forward( request, response); } catch (SQLException e) { e.printStackTrace(); }finally{ try { statement.close(); dbConnection.closeConnection(); } catch (SQLException e) { e.printStackTrace(); } } }else if(sname !=null&&sname.equals("course")){ setIndex(2); String num = request.getParameter("pageNo"); int n = Integer.parseInt(num); //flag涓�琛ㄧず浠庨椤佃繘鍏�灏嗛泦鍚堟暟鎹竻绌�骞朵粠鏁版嵁搴撹繑鍥炴暟鎹苟缁欓泦鍚坙a璧嬪�. if(getFlag()==0 && stu_id != null){ la.set(0,0);la.set(1,1);la.set(2,2);la.set(3,3);la.set(4,4); la.set(5,5);la.set(6,6);la.set(7,7);la.set(8,8);la.set(9,9); sql="select course_id from select_course where stu_id ='"+stu_id+"'"; try { ResultSet eq = statement.executeQuery(sql); while(eq.next()){ String cid = eq.getString("course_id"); int co_id = Integer.parseInt(cid); la.set((co_id-1), 10); } //鐢╨b灏唋a涓璫hecked灞炴�鏁版嵁淇濈暀骞跺瓨鍏ession,浠庣涓�〉鍒扮浜岄〉鏃跺彇鍑烘暟鎹祴鍊煎埌椤甸潰 ArrayList<Integer> lb = new ArrayList<Integer>(); System.out.print("lb的值为:"); for (int i = 0; i < 10; i++) { Integer integer = la.get(i); lb.add(integer); System.out.print(integer+" "); } System.out.println(); request.getSession().setAttribute("lb", lb); } catch (SQLException e) { e.printStackTrace(); } } if(stu_id !=null && !stu_id.equals("undefined")){ request.getSession().setAttribute("stu_id", stu_id); } //鑾峰彇鍓嶅彴checked灞炴�鏁版嵁 int[] tem = new int[10]; for (int i = 0; i < 10; i++) { String b = request.getParameter("a"+i); int pb = Integer.parseInt(b); tem[i]= pb; } if(n==1){ if(getFlag() != 0){ for (int i = 5; i < 10; i++) { la.set(i, tem[i]); } } setFlag(1); } if(n==2 &&getFlag() !=0){ if(getFlag() != 0){ for (int i = 0; i < 5; i++) { la.set(i, tem[i]); } } setFlag(2); } System.out.print("la的值为:"); for (int i = 0; i < 10; i++) { System.out.print(la.get(i)+" "); } System.out.println(""); System.out.println("-----------------------------------"); int min = (n-1)*5+1; int max = n*5; sql = "select * from course where id between "+min+" and "+max+""; ResultSet executeQuery; try { executeQuery = statement.executeQuery(sql); while (executeQuery.next()) { String id = executeQuery.getString("id"); String cname = executeQuery.getString("course_name"); String teachername = executeQuery.getString("teacher_name"); Course Course = new Course(); Course.setId(id); Course.setCourseName(cname); Course.setTeachername(teachername); ls2.add(Course); } request.getSession().setAttribute("ls2", ls2); } catch (SQLException e) { e.printStackTrace(); } String first = "<a href='#' onclick='select(1)'>第一页</a> "; String last = "<a href='#' onclick='select(2)'>第二页</a>"; if(n==1){ first="第一页"; } if(n==2){ last="第二页"; } StringBuffer page = new StringBuffer(); page.append(first); page.append(" "); page.append(last); request.getSession().setAttribute("page", page.toString()); request.getSession().setAttribute("la", la); for (int i = 0; i < 10; i++) { request.getSession().setAttribute("la"+i,la.get(i)); } request.getRequestDispatcher("WEB-INF/course_select.jsp").forward( request, response); }else if(sname !=null&&sname.equals("insert")){ int fl = getFlag(); System.out.println(fl); if(fl==1 || fl==0){ for (int i = 0; i < 5; i++) { String c = request.getParameter("a"+i); int pc = Integer.parseInt(c); la.set(i, pc); } } if(fl==2){ for (int i = 0; i < 5; i++) { String c = request.getParameter("a"+i); int pc = Integer.parseInt(c); la.set((i+5), pc); } } for (int i = 0; i < 10; i++) { System.out.print(la.get(i)+" "); } System.out.println(""); String stuid = (String)request.getSession().getAttribute("stu_id"); ArrayList<Integer> select = (ArrayList<Integer>)request.getSession().getAttribute("la"); int a = 0; //锟斤拷锟矫憋拷锟斤拷a锟叫讹拷选锟轿碉拷锟斤拷锟斤拷锟角凤拷锟斤拷锟斤拷3锟脚伙拷锟斤拷锟�锟斤拷. for(int i = 0; i < 10; i++){ Integer integer = select.get(i); if(integer==10){ a++; } } System.out.println("a的值为:"+a); PrintWriter out = response.getWriter