java学生选课系统

1、需求分析：写一个较为严谨的学生选课系统，实现学生可以选择多门选课课程，并将有效选课结果保存到数据库。学生需要登录后，才能选课。让学生可以在选课系统通过多种方式查询到要选的课程信息。/选课规则：1、每个学生可以选多门课程，多次选课的总学分不能超过6学分；2、不能重复选择一门课程；3、每一门课程的选课人数都有数量限制，当某门课程的选课名额满时，则应另选课程。4、凭用户名和密码登录，通过提交某一课程号来选课/总体设计方案：建立三个类：登录类register，选课类studentChooseCourse,数据库工具类JDBCUtil；一个SQL脚本文件用于生成数据库表结构和初始记录，以搭建数据库环境。

2、登录类register类，负责对用户的身份进行验证；工具类JDBCUtil用于实现连接，你可调用JDBCUtil的getConnection()方法等到链接。选课类studentChooseCourse用于，实现选课功能。其中包括几个主要方法：1、actionPerformed(ActionEvent) 用于监听用户“查询”和“提交”操作，并负责调用各种方法对其进行处理2、createSearchCourse()用于产生图形用户界面3、processBeforeCommit()用于对用户的“提交”查找进行验证，剔除无效的用户操作4、tryCommit()负责对有效的“提交”操作，进一步处理，并

3、将有效的操作结果时时保存到数据库，并更新数据库原有信息/本程序用到的知识点：数据库连接JDBC；SQL建表、插入输入、动态查询；图形用户界面的产生以及处理查询结果集并较好显示；程序设计基础知识。 /代码如下：;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.sql.*;import javax.swing.*;import javax.swing.table.DefaultTableModel;import school.schoolPicture.JdbcUtil;publi

4、c class StudentChooseCourse extends JFrame implements ActionListener JTextField jtfSearch = new JTextField(11);String columnNames = new String "课程ID", "课程名", "学时", "学分", "学期", "性质" ;DefaultTableModel dtmSearch = new DefaultTableModel(column

5、Names, 27);JTable jtSearch = new JTable(dtmSearch);JScrollPane jspSearch = new JScrollPane(jtSearch);JComboBox jcbSearch = new JComboBox();JTextField jtfSelectedCourse = new JTextField(10);Connection con = null;PreparedStatement ps = null;ResultSet rs = null;private static String usrName;private sta

6、tic String passwrd;public StudentChooseCourse(String usrName, String passwrd) createSearchCourse();this.usrName = usrName;this.passwrd = passwrd;public String getUsrName() return usrName;public void setUsrName(String usrName) this.usrName = usrName;public String getPasswrd() return passwrd;public vo

7、id setPasswrd(String passwrd) this.passwrd = passwrd; public void actionPerformed(ActionEvent e) String str = e.getActionCommand();if ("查询".trim().equals(str) int k = 1;while (k < 10) for (int i = 1; i < 7; i+) jtSearch.setValueAt(null, k - 1, i - 1);k+;searchAvailableCourse(); else

8、if ("提交".equals(str) boolean effect=processBeforeCommit(); if(effect=true)tryCommit();public boolean processBeforeCommit()int k = 1;while (k < 10) for (int i = 1; i < 7; i+) jtSearch.setValueAt(null, k - 1, i - 1);k+;String userInput = jtfSelectedCourse.getText().toString().trim().to

9、LowerCase();String sql = "select cno from coursexx where cno=? "boolean flagCourseExist = false;try ps = con.prepareStatement(sql);ps.setString(1, userInput);rs = ps.executeQuery();flagCourseExist = rs.next(); catch (Exception eC) eC.printStackTrace();if (!flagCourseExist) JOptionPane.show

10、MessageDialog(null, "该课程不存在，请重新输入");return false;PreparedStatement ps = null;sql = "select sum(grade) "+ "from (select x.sname , o,k.grade grade "+ "from coursexx k join choicesxx x "+ "on o=o and x.sname=?) result"String grade =null;try ps = con.pre

11、pareStatement(sql);ps.setString(1, usrName);rs = ps.executeQuery();while (rs.next() grade = rs.getString(1);if(grade=null)grade="0" catch (Exception rrr) rrr.printStackTrace();System.out.println("总学分：" + grade);if (Integer.parseInt(grade) > 6) JOptionPane.showMessageDialog(nul

12、l, "你已经选满6学分，系统将退出");this.setVisible(false);return false;sql = "select * from choicesxx where sname=? and cno=?"boolean flag = false;try ps = con.prepareStatement(sql);ps.setString(1, this.getUsrName();ps.setString(2, userInput);rs = ps.executeQuery();flag = rs.next(); catch (Exc

13、eption eaa) eaa.printStackTrace();if (flag) JOptionPane.showMessageDialog(null, "你已经选择了该课程。请另选课程");return false;return true;public void tryCommit() String userInput = jtfSelectedCourse.getText().toString().trim().toLowerCase();PreparedStatement ps;String sql = "select (Max-selectedCou

14、nt) as RemainedCount "+ "from Coursexx where cno=?"try ps = con.prepareStatement(sql);ps.setString(1, userInput);rs = ps.executeQuery();ResultSetMetaData meta = rs.getMetaData();int cols = meta.getColumnCount();int RemainedCount = -1;while (rs.next() RemainedCount = rs.getInt(1);Syste

15、m.out.println("RemainedCount:" + RemainedCount);if (RemainedCount > 0) sql = "insert into choicesxx values(?,?)"ps = con.prepareStatement(sql);ps.setString(1, this.getUsrName();ps.setString(2, userInput);ps.executeUpdate();JOptionPane.showMessageDialog(null, "选课成功： "

16、 + this.getUsrName()+ " 选了" + userInput + "." + "" + " 还有 " + RemainedCount+ " 人可以选该课程。");sql = "update CourseXX set selectedCount=selectedCount+1 where cno=?"ps = con.prepareStatement(sql);ps.setString(1, userInput);ps.executeUpdate();mit(

17、); catch (Exception es) es.printStackTrace();try con.rollback(); catch (Exception ey) ey.printStackTrace();public void searchAvailableCourse() if (JDBCUtil.getConnection() != null) System.out.println(JDBCUtil.getConnection();con = JDBCUtil.getConnection(); else con = JdbcUtil.getConnection();String

18、userInput = jtfSearch.getText().toString().trim().toLowerCase();String selectedItem = jcbSearch.getSelectedItem().toString().trim();System.out.println("User search:" + userInput);System.out.println("selectedItem:" + selectedItem);String sql = null;try if ("课程名".equals(s

19、electedItem) sql = "select cno,cname,hour,grade,term,isNeed from CourseXX where cname = ?"ps = con.prepareStatement(sql);ps.setString(1, userInput); else if ("课程ID".equals(selectedItem) sql = "select cno,cname,hour,grade,term,isNeed from CourseXX where cno = ?"ps = con.

20、prepareStatement(sql);ps.setString(1, userInput); else if ("学时".equals(selectedItem) sql = "select cno,cname,hour,grade,term,isNeed from CourseXX where hour = ?"ps = con.prepareStatement(sql);ps.setInt(1, Integer.parseInt(userInput); else if ("学分".equals(selectedItem) s

21、ql = "select cno,cname,hour,grade,term,isNeed from CourseXX where grade = ?"ps = con.prepareStatement(sql);ps.setInt(1, Integer.parseInt(userInput); else if ("学期".equals(selectedItem) sql = "select cno,cname,hour,grade,term,isNeed from CourseXX where term = ?"ps = con.p

22、repareStatement(sql);ps.setString(1, userInput);System.out.println(sql);rs = ps.executeQuery();mit();ResultSetMetaData meta = rs.getMetaData();int cols = meta.getColumnCount();String result = null;int k = 1;boolean flag = false;while (rs.next() for (int i = 1; i <= cols; i+) result = rs.getString

23、(i);System.out.println(result);jtSearch.setValueAt(result, k - 1, i - 1);k+;flag = true;if (flag = false) JOptionPane.showMessageDialog(null, "该课程不存在，请重新输入");return; catch (Exception ex) ex.printStackTrace();try con.rollback(); catch (Exception er) er.printStackTrace();public void createSe

24、archCourse() this.setLayout(new GridLayout(3, 1);JPanel jp1 = new JPanel();jp1.setLayout(new GridLayout(4, 1);JPanel jp2 = new JPanel();JPanel jp3 = new JPanel();JPanel jp10 = new JPanel();JPanel jp11 = new JPanel();JPanel jp12 = new JPanel();JPanel jp13 = new JPanel();JLabel jlSearch = new JLabel(&

25、quot; 学 生 选 课 系 统 ");jp11.add(jlSearch);jcbSearch.addItem(new String("课程名");jcbSearch.addItem(new String("课程ID");jcbSearch.addItem(new String("学时");jcbSearch.addItem(new String("学分");jcbSearch.addItem(new String("学期");jp12.add(jtfSearch);jp12.ad

26、d(jcbSearch);JButton jbOK = new JButton("查询");jbOK.addActionListener(this);jbOK.setSize(90, 20);jp13.add(jbOK);jp1.add(jp10);jp1.add(jp11);jp1.add(jp12);jp1.add(jp13);jp2.add(jspSearch);JLabel jlSelectedCourse = new JLabel("请输入课程ID：");JButton jbSelectedCourse = new JButton("

27、提交");jbSelectedCourse.addActionListener(this);jp3.add(jlSelectedCourse);jp3.add(jtfSelectedCourse);jp3.add(jbSelectedCourse);this.add(jp1);this.add(jp2);this.add(jp3);this.setVisible(true);this.setSize(485, 600);public static void main(String args) /String usrName = "xuliang"/String p

28、asswrd = "123"new StudentChooseCourse(usrName, passwrd);drop table registerXu;create table registerXu (id varchar(20),userName varchar(20),passWord varchar(20),identify varchar(20);insert into registerXu values('s001','xuliang','123','学生');insert into regist

29、erXu values('s002','xuliang2','1234','学生');insert into registerXu values('j001','jack','12345','学生');insert into registerXu values('001','user','user','学生');insert into registerXu values('z001',&#

30、39;zlm','corejava','老师');String sql = "select * from registerXu "+ "where userName=? and passWord=? and identify=?"/table 2:Coursexx课程表drop table Coursexx;create table Coursexx(cno varchar(20) primary key,cname varchar(20),hour Int,grade Int,term varchar(20),i

31、sNeed varchar(20), selectedCount Int ,Max Int);insert into Coursexx values('c001','CoreJava',50,5,'201007','NoNecessary',0,50);insert into Coursexx values('c002','XML',20,2,'201008','NoNecessary',0,40);insert into Coursexx values('c

32、003','HIBERNATE',20,4,'201008','NoNecessary',0,30);insert into Coursexx values('c004','SQL',20,4,'201006','NoNecessary',0,5);insert into Coursexx values('c005','JDBC',20,2,'201008','NoNecessary',0,3);insert i

33、nto Coursexx values('c006','AJAX',20,2,'201010','NoNecessary',0,1);insert into Coursexx values('c007','JSP',100,8,'201009','NoNecessary',0,1sql = "select cno,cname,hour,grade,term,isNeed from CourseXX where cname = ?" /table 3

34、:学生表-drop table studentxx;create table studentxx(sid varchar(20),sname varchar(20) primary key,sex varchar(20),birthday varchar(20),className varchar(20), image varchar(20);insert into studentxx values('s001','xuliang','male','19901124','sd1003','good'

35、);insert into studentxx values('s002','xuliang2','male','19851124','sd0910','good');insert into studentxx values('j001','jack','male','19881124','sd1003','good');insert into studentxx values('001'

36、,'user','male','19901124','sd1005','good');insert into studentxx values('s003','sisi','female','19880124','sd1007','good');insert into studentxx values('as003','crystal','female','1988

37、0124','asd1007','good');drop table choicesxx;create table choicesxx(sname varchar(20) references studentxx(sname),cno varchar(20) references coursexx(cno);package school;import javax.swing.*;import school.schoolPicture.JdbcUtil;import java.sql.*;import java.awt.*;import java.awt.

38、event.*;public class Register implements ActionListener JFrame jf = new JFrame("学生成绩管理与选课系统");JTextField jtfUserName = new JTextField(10);JPasswordField jpfPassWord = new JPasswordField(10);JComboBox identify = new JComboBox();public Register() CreateRegisterGUI();public void actionPerform

39、ed(ActionEvent e) String str = e.getActionCommand();if (str.equalsIgnoreCase("登录") processLogin(); else if (str.equalsIgnoreCase("取消") jtfUserName.setText("");jpfPassWord.setText(""); else if (str.equalsIgnoreCase("注册") new CreateLogin();public void

40、processLogin() Connection con = null;if (JdbcUtil.class = null) con = JdbcUtil.getConnection(); else con = JDBCUtil.getConnection();String usrName = jtfUserName.getText().trim();String passwrd = new String(jpfPassWord.getPassword().trim();String ident = identify.getSelectedItem().toString().trim();S

41、tring sql = "select * from registerXu "+ "where userName=? and passWord=? and identify=?"System.out.println(usrName + ":" + passwrd + ":" + ident);try PreparedStatement ps = con.prepareStatement(sql);ps.setString(1, usrName);ps.setString(2, passwrd);ps.setStri

42、ng(3, ident);ResultSet rs = ps.executeQuery();StringBuffer sb = new StringBuffer("");ResultSetMetaData meta = rs.getMetaData();int cols = meta.getColumnCount();records in database:while (rs.next() for (int i = 1; i < cols; i+) sb.append(meta.getColumnName(i);sb.append(rs.getString(i);if

43、 (sb.length() < 1) JOptionPane.showMessageDialog(null, "用户名或密码错误"); else if (sb.length() >= 1) if (ident.equals("student") new StudentChooseCourse(usrName, passwrd);jf.setVisible(false); else if (ident.equals("teacher") new TeacherEntered();jf.setVisible(false); e

44、lse if (ident.equals("admin") catch (Exception er) er.printStackTrace();public void CreateRegisterGUI() jf.setLayout(new GridLayout(5, 1);JPanel jp1 = new JPanel();JLabel jl1 = new JLabel("学生成绩管理系统");jp1.add(jl1);jf.add(jp1);JPanel jp2 = new JPanel();JLabel jl2 = new JLabel("

45、;用户名:");jp2.add(jl2);jp2.add(jtfUserName);jf.add(jp2);JPanel jp3 = new JPanel();JLabel passWord = new JLabel("密 码:");jp3.add(passWord);jp3.add(jpfPassWord);jf.add(jp3);JPanel jp4 = new JPanel();JLabel jl4 = new JLabel("身 份:");/ identify.addItem(new String("学生 ");identify.addItem(new String("student ");/