javaweb网上选课mysql

网上选课mysql"/>

javaweb网上选课mysql

选课系统中用到了4个表，分别是classs、yonghu、teacher、student。在用户中存放管理员的信息name和password以及id，在另三个表中存放对应的数据如图：

calss：

teacher：

student：

yonghu：

首先root用户提前定义好名字以及密码，老师和学生可以由root进行增加

登录时根据选择的用户类型将输入的用户名和密码与数据库中对应的进行判断，根据用户的不同类型跳转到不同的界面。登陆成功后将登录用户的名字存放到session中，之后进行一系列例如更改个人信息、添加课程时直接调用session中的当前用户的名字进行更改。

下面是代码：

DAO：

1 packageDao;2

3 importjava.sql.Connection;4 importjava.sql.Statement;5 importjava.util.ArrayList;6 importjava.util.List;7 importjava.sql.ResultSet;8 importDBUtil.DBUtil;9 importEntity.teacher;10 importEntity.student;11 importEntity.Classs;12 public classDao {13 publicString dopost(String username,String password,String leibie) {14 String i="-1";15 String sql=null;16 if(leibie.equals("老师"))17 {18 sql="select * from teacher where xingming = '"+username+"'";19 }20 else if(leibie.equals("学生"))21 {22 sql="select * from student where xingming = '"+username+"'";23 }24 else if(leibie.equals("管理员"))25 {26 sql="select * from yonghu where name = '"+username+"'";27 }28 Connection conn =DBUtil.getConn();29 Statement state = null;30 ResultSet rs = null;31 try{32 state =conn.createStatement();33 rs =state.executeQuery(sql);34 while(rs.next()) {35 String password1 = rs.getString("password");36 if(password.equals(password1)) {37 i=rs.getString("id");38 }39 break;40 }41 }catch(Exception e) {42 e.printStackTrace();43 } finally{44 DBUtil.close(rs,state, conn);45 }46 returni;47 }48 public booleanteadd(teacher tea) {49

50 String sql = "insert into teacher(gonghao,xingbie,xingming,xuexiao,zhicheng,password,id) values('"+ tea.getGonghao() + "','"+ tea.getXingbie() +"','"+ tea.getXingming() +"','" + tea.getXuexiao() +"','"+ tea.getZhicheng() +"' , '"+tea.getPassword()+"' , '"+tea.getId()+"')";51 Connection conn =DBUtil.getConn();52 Statement state = null;53 boolean f = false;54 int a = 0;55

56 try{57 state =conn.createStatement();58 a=state.executeUpdate(sql);59 } catch(Exception e) {60 e.printStackTrace();61 } finally{62

63 DBUtil.close(state, conn);64 }65

66 if (a > 0) {67 f = true;68 }69 returnf;70

71 }72 public booleanstadd(student stu) {73

74 String sql = "insert into student(xuehao,xingming,xingbie,banji,zhuanye,password,id) values('"+ stu.getXuehao() + "','"+ stu.getXingming() +"','"+ stu.getXingbie() +"','" + stu.getBanji() +"','"+ stu.getZhuanye() +"' , '"+stu.getPassword()+"' , '"+stu.getId()+"')";75 Connection conn =DBUtil.getConn();76 Statement state = null;77 boolean f = false;78 int a = 0;79

80 try{81 state =conn.createStatement();82 a=state.executeUpdate(sql);83 } catch(Exception e) {84 e.printStackTrace();85 } finally{86

87 DBUtil.close(state, conn);88 }89

90 if (a > 0) {91 f = true;92 }93 returnf;94

95 }96 public booleanclaadd(String bianhao,String name,String number,String prename) {97

98

99 String sql = "insert into classs(clahao,claname,number,tea,num) values('"+ bianhao + "','"+ name +"','"+ number +"','"+prename+"', '0')";100 Connection conn =DBUtil.getConn();101 Statement state = null;102 boolean f = false;103 int a = 0;104

105 try{106 state =conn.createStatement();107 a=state.executeUpdate(sql);108 } catch(Exception e) {109 e.printStackTrace();110 } finally{111

112 DBUtil.close(state, conn);113 }114

115 if (a > 0) {116 f = true;117 }118 returnf;119

120 }121 public booleanteagai(String leibie,String neirong,String prename) {122

123 String sql = "update teacher set "+ leibie+" = '"+ neirong+"' "+"where xingming = '"+prename+"'";124 Connection conn =DBUtil.getConn();125 Statement state = null;126 boolean f = false;127 int a = 0;128

129 try{130 state =conn.createStatement();131 a=state.executeUpdate(sql);132 } catch(Exception e) {133 e.printStackTrace();134 } finally{135

136 DBUtil.close(state, conn);137 }138

139 if (a > 0) {140 f = true;141 }142 returnf;143

144 }145 public booleanstugai(String leibie,String neirong,String prename) {146

147 String sql = "update student set "+ leibie+" = '"+ neirong+"' "+"where xingming = '"+prename+"'";148 Connection conn =DBUtil.getConn();149 Statement state = null;150 boolean f = false;151 int a = 0;152

153 try{154 state =conn.createStatement();155 a=state.executeUpdate(sql);156 } catch(Exception e) {157 e.printStackTrace();158 } finally{159

160 DBUtil.close(state, conn);161 }162

163 if (a > 0) {164 f = true;165 }166 returnf;167

168 }169 public Listlist(){170 String sql="select * from classs";171 Connection conn =DBUtil.getConn();172 Statement state =null;173 ResultSet rs = null;174 List list = new ArrayList<>();175 try{176 state =conn.createStatement();177 rs =state.executeQuery(sql);178 Classs bean = null;179 while(rs.next()) {180 String claname1=rs.getString("claname");181 String clahao1=rs.getString("clahao");182 String number1=rs.getString("number");183 String tea1=rs.getString("tea");184 String num1=rs.getString("num");185 bean = newClasss(clahao1,claname1,number1,tea1,num1);186 list.add(bean);187

188 }189

190 }catch(Exception e) {191 e.printStackTrace();192 } finally{193 DBUtil.close(rs,state, conn);194 }195 returnlist;196 }197 public booleanjia(String num,String number,String clahao) {198 boolean f=false;199 int n1=Integer.parseInt(num);200 int n2=Integer.parseInt(number);201 if(n1

216 DBUtil.close(state, conn);217 }218

219 if (a > 0) {220 f = true;221 }222

223 }224 returnf;225 }226 }

DBUtil：

1 packageDBUtil;2

3

4 importjava.sql.Connection;5 importjava.sql.DriverManager;6 importjava.sql.PreparedStatement;7 importjava.sql.ResultSet;8 importjava.sql.SQLException;9 importjava.sql.Statement;10

11

12 public classDBUtil {13

14 public static String db_url = "**********";15 public static String db_user = "****";16 public static String db_pass = "******";17

18 public staticConnection getConn () {19 Connection conn = null;20

21 try{22 Class.forName("com.mysql.jdbc.Driver");23 conn =DriverManager.getConnection(db_url, db_user, db_pass);24 } catch(Exception e) {25 e.printStackTrace();26 }27

28 returnconn;29 }//end getConn

30

31 public static voidclose (Statement state, Connection conn) {32 if (state != null) {33 try{34 state.close();35 } catch(SQLException e) {36 e.printStackTrace();37 }38 }39

40 if (conn != null) {41 try{42 conn.close();43 } catch(SQLException e) {44 e.printStackTrace();45 }46 }47 }48

49 public static voidclose (ResultSet rs, Statement state, Connection conn) {50 if (rs != null) {51 try{52 rs.close();53 } catch(SQLException e) {54 e.printStackTrace();55 }56 }57

58 if (state != null) {59 try{60 state.close();61 } catch(SQLException e) {62 e.printStackTrace();63 }64 }65

66 if (conn != null) {67 try{68 conn.close();69 } catch(SQLException e) {70 e.printStackTrace();71 }72 }73 }74

75 public static void main(String[] args) throwsSQLException {76 Connection conn =getConn();77 PreparedStatement pstmt = null;78 ResultSet rs = null;79 String sql ="select * from yonghu";80 pstmt =conn.prepareStatement(sql);81 rs =pstmt.executeQuery();82 if(rs.next()){83 System.out.println("连接成功");84 }else{85 System.out.println("连接失败");86 }87 }88 }

Entity中定义了4个类：

classs：

1 packageEntity;2

3 public classClasss {4 privateString clahao;5 privateString claname;6 privateString number;7 privateString tea;8 privateString num;9 publicString getClahao() {10 returnclahao;11 }12 public voidsetClahao(String clahao) {13 this.clahao =clahao;14 }15 publicString getClaname() {16 returnclaname;17 }18 public voidsetClaname(String claname) {19 this.claname =claname;20 }21 publicString getNumber() {22 returnnumber;23 }24 public voidsetNumber(String number) {25 this.number =number;26 }27 publicString getTea() {28 returntea;29 }30 public voidsetTea(String tea) {31 this.tea =tea;32 }33 publicString getNum() {34 returnnum;35 }36 public voidsetNum(String num) {37 this.num =num;38 }39 publicClasss(String clahao,String claname,String number, String tea,String num) {40 super();41 this.clahao=clahao;42 this.claname=claname;43 this.number=number;44 this.tea=tea;45 this.num=num;46 }47

48 }

另外三个是user、teacher、student结构和这个一样就不上了。

Servlet：

1 packageServlet;2 importjava.io.IOException;3 importjava.util.List;4

5 importjavax.servlet.ServletException;6 importjavax.servlet.annotation.WebServlet;7 importjavax.servlet.http.HttpServlet;8 importjavax.servlet.http.HttpServletRequest;9 importjavax.servlet.http.HttpServletResponse;10 importjavax.servlet.http.HttpSession;11 importEntity.teacher;12 importEntity.User;13 importEntity.student;14 importEntity.Classs;15 importDao.Dao;16

17

18

19

20 @WebServlet("/Servlet")21 public class Servlet extendsHttpServlet {22 private static final long serialVersionUID = 1L;23

24

25 publicServlet() {26 super();27

28 }29 protected void service(HttpServletRequest req, HttpServletResponse resp) throwsServletException, IOException {30 req.setCharacterEncoding("utf-8");31 String method = req.getParameter("method");32 if ("dopost".equals(method)) {33 dopost(req,resp);34 }35 if ("tiao".equals(method)) {36 tiao(req,resp);37 }38 if ("teadd".equals(method)) {39 teadd(req,resp);40 }41 if ("stadd".equals(method)) {42 stadd(req,resp);43 }44 if ("claadd".equals(method)) {45 claadd(req,resp);46 }47 if ("teagai".equals(method)) {48 teagai(req,resp);49 }50 if ("stugai".equals(method)) {51 stugai(req,resp);52 }53 if("list".equals(method)){54 list(req,resp);55 }56 if("jia".equals(method)) {57 jia(req,resp);58 }59

60 }61

62

63 private void dopost(HttpServletRequest req, HttpServletResponse resp) throwsIOException, ServletException{64

65 req.setCharacterEncoding("utf-8");66 String username = req.getParameter("username");67 String password = req.getParameter("password");68 String leibie=req.getParameter("leibie");69 HttpSession session =req.getSession();70 session.setAttribute("prename",username);71 Dao dao=newDao();72 String id=dao.dopost(username, password,leibie);73 if(id.equals("-1")) {74 req.setAttribute("message", "登录失败！");75 req.getRequestDispatcher("index.jsp").forward(req,resp);76 }77 else if(id.equals("0")) {78 req.setAttribute("message", "登陆成功！");79 req.getRequestDispatcher("allteacher.jsp").forward(req,resp);80 }81 else if(id.equals("1")) {82 req.setAttribute("message", "登陆成功！");83 req.getRequestDispatcher("allstudent.jsp").forward(req,resp);84 }85 else if(id.equals("2")) {86 req.setAttribute("message", "登陆成功！");87 req.getRequestDispatcher("root.jsp").forward(req,resp);88 }89 }90 private void tiao(HttpServletRequest req, HttpServletResponse resp) throwsIOException, ServletException{91 req.setCharacterEncoding("utf-8");92 String leibie=req.getParameter("leibie");93 if(leibie.equals("学生")) {94 req.setAttribute("message", "请开始添加学生信息！");95 req.getRequestDispatcher("student.jsp").forward(req,resp);96 }97 if(leibie.equals("老师")) {98 req.setAttribute("message", "请添加老师信息！");99 req.getRequestDispatcher("teacher.jsp").forward(req,resp);100 }101 }102 private void teadd(HttpServletRequest req, HttpServletResponse resp) throwsIOException, ServletException{103 req.setCharacterEncoding("utf-8");104 String gonghao=req.getParameter("gonghao");105 String xingming=req.getParameter("xingming");106 String xingbie=req.getParameter("xingbei");107 String xuexiao=req.getParameter("xuexiao");108 String zhicheng=req.getParameter("zhicheng");109 String password=req.getParameter("password");110 String id="0";111 teacher tea=newteacher(gonghao,xingbie,xingming,xuexiao,zhicheng,password,id);112 Dao dao =newDao();113 boolean f=dao.teadd(tea);114 if(f) {115 req.setAttribute("message", "添加成功！");116 req.getRequestDispatcher("root.jsp").forward(req,resp);117 } else{118 req.setAttribute("message", "添加失败！");119 req.getRequestDispatcher("teacher.jsp").forward(req,resp);120 }121 }122 private void stadd(HttpServletRequest req, HttpServletResponse resp) throwsIOException, ServletException{123 req.setCharacterEncoding("utf-8");124 String xuehao=req.getParameter("xuehao");125 String xingming=req.getParameter("xingming");126 String xingbie=req.getParameter("xingbei");127 String banji=req.getParameter("banji");128 String zhuanye=req.getParameter("zhuanye");129 String password=req.getParameter("password");130 String id="1";131 student stu=newstudent(xuehao,xingming,xingbie,banji,zhuanye,password,id);132 Dao dao =newDao();133 boolean f=dao.stadd(stu);134 if(f) {135 req.setAttribute("message", "添加成功！");136 req.getRequestDispatcher("root.jsp").forward(req,resp);137 } else{138 req.setAttribute("message", "添加失败！");139 req.getRequestDispatcher("teacher.jsp").forward(req,resp);140 }141 }142 private void claadd(HttpServletRequest req, HttpServletResponse resp) throwsIOException, ServletException{143 req.setCharacterEncoding("utf-8");144 HttpSession session =req.getSession();145 String prename=null;146 prename=(String)session.getAttribute("prename");147 String bianhao=req.getParameter("hao");148 String name=req.getParameter("name");149 String number=req.getParameter("number");150 Dao dao =newDao();151 boolean f=dao.claadd(bianhao,name,number,prename);152 if(f) {153 req.setAttribute("message", "添加成功！");154 req.getRequestDispatcher("allteacher.jsp").forward(req,resp);155 } else{156 req.setAttribute("message", "添加失败！");157 req.getRequestDispatcher("addclass.jsp").forward(req,resp);158 }159 }160 private void teagai(HttpServletRequest req, HttpServletResponse resp) throwsIOException, ServletException{161 req.setCharacterEncoding("utf-8");162 HttpSession session =req.getSession();163 String prename=null;164 prename=(String)session.getAttribute("prename");165 String leibie=req.getParameter("leibie");166 String neirong=req.getParameter("neirong");167

168 Dao dao =newDao();169 boolean f=dao.teagai(leibie,neirong,prename);170 if(f) {171 req.setAttribute("message", "修改成功！");172 req.getRequestDispatcher("allteacher.jsp").forward(req,resp);173 } else{174 req.setAttribute("message", "修改失败！");175 req.getRequestDispatcher("updatetea.jsp").forward(req,resp);176 }177 }178 private void stugai(HttpServletRequest req, HttpServletResponse resp) throwsIOException, ServletException{179 req.setCharacterEncoding("utf-8");180 HttpSession session =req.getSession();181 String prename=null;182 prename=(String)session.getAttribute("prename");183 String leibie=req.getParameter("leibie");184 String neirong=req.getParameter("neirong");185 Dao dao =newDao();186 boolean f=dao.stugai(leibie,neirong,prename);187 if(f) {188 req.setAttribute("message", "修改成功！");189 req.getRequestDispatcher("allstudent.jsp").forward(req,resp);190 } else{191 req.setAttribute("message", "修改失败！");192 req.getRequestDispatcher("updatestu.jsp").forward(req,resp);193 }194 }195 private void list(HttpServletRequest req, HttpServletResponse resp) throwsIOException, ServletException{196

197 Dao dao=newDao();198 List holds =dao.list();199 req.setAttribute("holds", holds);200 req.getRequestDispatcher("xuan.jsp").forward(req,resp);201 }202 private void jia(HttpServletRequest req, HttpServletResponse resp) throwsIOException, ServletException{203 req.setCharacterEncoding("UTF-8");204 String num=req.getParameter("num");205 String number=req.getParameter("number");206 String clahao=req.getParameter("clahao");207 Dao dao=newDao();208 boolean f=dao.jia(num, number, clahao);209 if(f) {210 req.setAttribute("message", "选课成功！");211 req.getRequestDispatcher("allstudent.jsp").forward(req,resp);212 } else{213 req.setAttribute("message", "选课失败！");214 req.getRequestDispatcher("xuan.jsp").forward(req,resp);215 }216 }217 }

然后就是各个jsp界面了

index：

1

2 pageEncoding="UTF-8"%>

3

4

5

6

7

登录

8

9

10

11 Object message = request.getAttribute("message");12 if (message != null && !"".equals(message)) {13 %>

14

15 alert("");16 var asd=request.getAttribute("username");17

18

19 }20 %>

21

22

23 用户名

24

25

26 密码

27

28

29

类别

30 学生

31 老师

32 管理员

33

34

35

36

37

38

39

40

root：

1

2 pageEncoding="UTF-8"%>

3

4

5

6

7

当前位置：添加信息

8

9

10

11 Object message = request.getAttribute("message");12 if (message != null && !"".equals(message)) {13 %>

14

15 alert("");16 var asd=request.getAttribute("username");17

18

19 }20 %>

21

22

23

类别

24 学生

25 老师

26

27

28

29

30

31

32

33

34

35

36

37

38

teacher：

添加老师信息

var asd=request.getAttribute("name");

工号：
姓名：
性别：	男女
学校：
职称：
密码：

student：

添加学生信息

var asd=request.getAttribute("name");

学号：
姓名：
性别：	男 name="xingbei" type="radio" value="女" />女
班级：
专业：
密码：

allteacher：

1

2 pageEncoding="UTF-8"%>

3

4

5

6

7

当前位置：主页

8

9

10

11 Object message = request.getAttribute("message");12 if (message != null && !"".equals(message)) {13 %>

14

15 alert("");16 var asd=request.getAttribute("username");17

18

19 }20 %>

21

24

25

26

27

当前用户：${prename }

28

29

30 修改个人信息

31

32

33

34 添加课程信息

35

36

37

38

39

40

41

42

43

44

45

46

allstudent：

1

2 pageEncoding="UTF-8"%>

3

4

5

6

7

8

当前位置：主页

9

10

11

12 Object message = request.getAttribute("message");13 if (message != null && !"".equals(message)) {14 %>

15

16 alert("");17 var asd=request.getAttribute("username");18

19

20 }21 %>

22

25

26

27

28

当前用户：${prename }

29

30

31 修改个人信息

32

33

34

35 选课

36

37

38

39

40

41

42

43

44

45

46

addclass：

1

2 pageEncoding="UTF-8"%>

3

4

5

6

7

添加老师信息

8

9

10

11 Object message = request.getAttribute("message");12 if (message != null && !"".equals(message)) {13 %>

14

15 alert("");16 var asd=request.getAttribute("name");17

18

19 }20 %>

21

22

23

24

25

课程编号：

26

27

28

29

课程名称：

30

31

32

33

选课人数：

34

35

36

37

38

39

40

41

42

43

44

45

46

47

updatestu：

1

2 pageEncoding="UTF-8"%>

3

4

5

6

7

8

Insert title here

9

10

11

12 Object message = request.getAttribute("message");13 if(message!=null && !"".equals(message)){14 %>

15

16 alert("");17

18

19

20 String prename=null;21 prename=request.getParameter(prename);22 %>

23

24

25

26

${prename }

27

28

29

30

31

类别

32

33 xuehao

34 xingming

35 xingbie

36 banji

37 zhuanye

38

39

40

41

42

43

44

45

46

47

48

49

50

updatetea：

1

2 pageEncoding="UTF-8"%>

3

4

5

6

7

Insert title here

8

9

10

11 Object message = request.getAttribute("message");12 if(message!=null && !"".equals(message)){13 %>

14

15 alert("");16

17

18

19 String prename=null;20 prename=request.getParameter(prename);21 %>

22

23

当前用户：${prename }

24

25

26

27

类别

28 gonghao

29 xingming

30 xingbie

31 xuexiao

32 zhicheng

33

34

35

36

37

38

39

40

41

42

43

44

45

xuan：

1

2 pageEncoding="UTF-8"%>

3

4

5

6

7

8

9

课程信息

10

11

12

13 Object message = request.getAttribute("message");14 if (message != null && !"".equals(message)) {15 %>

16

17 alert("");18 var asd=request.getAttribute("username");19

20

21 }22 %>

23

24

25

课程编号

26

课程名称

27

任课老师

28

已选人数

29

课程人数

30

31

32

33

34

${item.clahao}

35

${item.claname}

36

${item.tea}

37

${item.num}

38

${item.number}

39

选课

40

41

42

43

44

45

46

47

这就是全部的代码了，做这个系统的过程中我遇到的难点是如何保持一个用户的登录状态，可以再之后这个用户进行操作时简单便捷的获取当前用户的信息，找了资料之后发现session对象符合我的要求，便开始在我原来的代码上进行更改。最终实现了登录状态的保持。