首页 > > 网页制作 > css >

学生选课系统v1.0

2019-12-19 16:00:39来源：博客园 阅读 ()

新老客户大回馈,云服务器低至5折

学生选课系统v1.0

最近两天写了下老师课上留的作业：学生选课系统。感觉自己写的特别麻烦，思路特别不清晰，平常自己总会偷懒，一些太麻烦细节的功能就不去实现了，用简单的功能来替代，直到自己这回写完这个系统(但自己写的比较low，只有后台功能，前台几乎没有)，发现一些功能虽然繁琐，但多写几次就不会感到麻烦，反而自己的思维会变得更清楚。

系统：三种用户：管理员，教师，学生。管理员来添加教师和学生，教师可以添加自己的课程，查看选课学生的信息，修改个人信息，学生可以实现选课，浏览课程信息，修改个人信息等。

主要思路：通过将用户的账号和密码同数据库相应的数据进行比对验证登陆，用户登陆时选择自己的身份。将学生，老师，课程，选课信息分别储存在数据库中。人数达到上限后改变课程的状态。重复选课后台给出提示（这个写的不太好，应在前台告知客户），不添加数据到数据库中。

这里只给出核心的代码（Dao层），其余可以自己比较简单。

package dao;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.http.HttpServletRequest;

import util.DButil;
import bean.De;
import bean.Lesson;
import bean.Student;
import bean.Teacher;

public class Function {

    // 验证用户是否存在
    public static boolean search(String stunumber, String code, String id, HttpServletRequest request) {
        int temp = 0;
        Connection conn = DButil.getConn();
        String sql = null;
        Statement sta = null;
        if (id.contentEquals("老师")) {
            sql = "select * from teacher";
        } else {
            sql = "select * from student";
        }

        try {
            sta = conn.createStatement();
            ResultSet res = sta.executeQuery(sql);
            while (res.next()) {
                String pn = res.getString("num");
                String name = res.getString("name");
                request.setAttribute("na", name);
                if (stunumber.equals(pn) && code.equals("123")) {
                    temp = 1;
                    break;
                }
            }
            res.close();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DButil.close(sta, conn);
        }
        if (temp == 0)
            return false;
        else
            return true;
    }

    // 增加老师数据
    public static void addT(String stunumber, String name, String sex, String college, String department)
            throws SQLException {
        String sql = "INSERT INTO TEACHER(num,name,sex,college,job) VALUES('" + stunumber + "','" + name + "','" + sex
                + "','" + college + "','" + department + "')";
        Connection conn = DButil.getConn();
        conn.setAutoCommit(false);
        PreparedStatement preparedStatement = conn.prepareStatement(sql);
        preparedStatement.executeUpdate();
        conn.commit();
        conn.close();
    }

    // 增加学生数据
    public static void addS(String stunumber, String name, String sex, String college, String department)
            throws SQLException {
        String sql = "INSERT INTO STUDENT(num,name,sex,class,major) VALUES('" + stunumber + "','" + name + "','" + sex
                + "','" + college + "','" + department + "')";
        Connection conn = DButil.getConn();
        conn.setAutoCommit(false);
        PreparedStatement preparedStatement = conn.prepareStatement(sql);
        preparedStatement.executeUpdate();
        conn.commit();
        conn.close();
    }

    // 增加课程信息
    public static void addC(String stunumber, String name, String sex, String college) throws SQLException {
        String sql = "INSERT INTO kecheng(number,name,people,teacher) VALUES('" + stunumber + "','" + name + "','" + sex
                + "','" + college + "')";
        Connection conn = DButil.getConn();
        conn.setAutoCommit(false);
        PreparedStatement preparedStatement = conn.prepareStatement(sql);
        preparedStatement.executeUpdate();
        conn.commit();
        conn.close();
    }

    // 修改老师信息
    public static void updataT(String name, String sex, String college, String de) throws SQLException {

        String sql = "update teacher set sex='" + sex + "',college='" + college + "',job='" + de + "' where name='"
                + name + "'";
        Connection conn = DButil.getConn();
        conn.setAutoCommit(false);
        PreparedStatement preparedStatement = conn.prepareStatement(sql);
        preparedStatement.executeUpdate();
        conn.commit();
        conn.close();
    }

    // 修改学生数据
    public static void updataS(String name, String sex, String college, String de) throws SQLException {

        String sql = "update student set sex='" + sex + "',class='" + college + "',major='" + de + "' where name='"
                + name + "'";
        Connection conn = DButil.getConn();
        conn.setAutoCommit(false);
        PreparedStatement preparedStatement = conn.prepareStatement(sql);
        preparedStatement.executeUpdate();
        conn.commit();
        conn.close();
    }

    // 返回全部课程信息
    public static List<De> getDe_1() throws SQLException {
        List<De> list = new ArrayList<De>();
        String sql = "select * from kecheng ";
        Connection conn = DButil.getConn();
        try {
            // 连接对象coon调用createStatement()方法，创建一个执行SQL语句的对象st
            Statement st = conn.createStatement();
            // 执行SQL语句中的对象st调用executeQuery()方法，执行查询语句，将查询到的结果返回到一个结果集中
            ResultSet rs = st.executeQuery(sql);
            // 遍历结果集对象
            while (rs.next()) {
                De vol = new De();
                vol.setNumber(rs.getString("number"));
                vol.setName(rs.getString("name"));
                vol.setPeople(rs.getInt("people"));
                vol.setTeacher(rs.getString("teacher"));
                list.add(vol);
            }
        } catch (Exception e) {
            System.out.println(e.getMessage());
        } finally {
            if (conn != null) {
                conn.close();
            }
        }
        return list;
    }

    // 返回可选课程信息
    public static List<De> getDe() throws SQLException {
        List<De> list = new ArrayList<De>();
        String sql = "select * from kecheng where status='0' ";
        Connection conn = DButil.getConn();
        try {
            // 连接对象coon调用createStatement()方法，创建一个执行SQL语句的对象st
            Statement st = conn.createStatement();
            // 执行SQL语句中的对象st调用executeQuery()方法，执行查询语句，将查询到的结果返回到一个结果集中
            ResultSet rs = st.executeQuery(sql);
            // 遍历结果集对象
            while (rs.next()) {
                De vol = new De();
                vol.setNumber(rs.getString("number"));
                vol.setName(rs.getString("name"));
                vol.setPeople(rs.getInt("people"));
                vol.setTeacher(rs.getString("teacher"));
                list.add(vol);
            }
        } catch (Exception e) {
            System.out.println(e.getMessage());
        } finally {
            if (conn != null) {
                conn.close();
            }
        }
        return list;
    }

    // 返回老师详细信息
    public static Teacher getTeacheer(String name) throws SQLException {
        Teacher te = new Teacher();
        String sql = "select * from Teacher where name='" + name + "' ";
        Connection conn = DButil.getConn();
        try {
            Statement st = conn.createStatement();
            ResultSet rs = st.executeQuery(sql);
            if (rs.next()) {
                te.setNum(rs.getString("num"));
                te.setName(rs.getString("name"));
                te.setSex(rs.getString("sex"));
                te.setCollege(rs.getString("college"));
                te.setJob(rs.getString("job"));
            }
        } catch (Exception e) {
            System.out.println(e.getMessage());
        } finally {
            if (conn != null) {
                conn.close();
            }
        }
        return te;
    }

    // 学生选课信息
    public static void stu_lesson(String s_name, String le_number) throws SQLException {
        String lesson_number = le_number;
        String lesson_name = null;
        String teacher_name = null;
        String teacher_number = null;
        String stu_name = s_name;
        String stu_num = null;
        Connection conn = null;
        int a = 0;
        int count = 0;
        boolean temp = true;
        try {
            String sql = "select * from chooseke  where lesson_num='" + le_number + "' and stu_name='" + s_name + "' ";
            conn = DButil.getConn();
            // 连接对象coon调用createStatement()方法，创建一个执行SQL语句的对象st
            Statement st = conn.createStatement();
            // 执行SQL语句中的对象st调用executeQuery()方法，执行查询语句，将查询到的结果返回到一个结果集中
            ResultSet rs = st.executeQuery(sql);
            // 遍历结果集对象
            if (rs.next()) {
                temp = false;
            }
            if (temp == true) {
                sql = "select * from kecheng where number='" + le_number + "' ";
                rs = st.executeQuery(sql);
                if (rs.next()) {
                    lesson_name = rs.getString("name");
                    teacher_name = rs.getString("teacher");
                }

                sql = "select * from teacher where name='" + teacher_name + "' ";
                rs = st.executeQuery(sql);
                // 遍历结果集对象
                if (rs.next()) {
                    teacher_number = rs.getString("num");
                }

                sql = "select * from student where name='" + stu_name + "' ";
                rs = st.executeQuery(sql);
                // 遍历结果集对象
                if (rs.next()) {
                    stu_num = rs.getString("num");
                }

                sql = "select * from kecheng where name='" + lesson_name + "' ";
                rs = st.executeQuery(sql);
                if (rs.next()) {
                    a = rs.getInt("people");
                }

                sql = "select * from chooseke where lesson_name='" + lesson_name + "' ";
                rs = st.executeQuery(sql);
                while (rs.next()) {
                    count++;
                    System.out.println(count);
                }

                if (count < a) {
                    sql = "INSERT INTO CHOOSEKE(lesson_num,lesson_name,teacher_num,teacher_name,stu_number,stu_name) VALUES('"
                            + lesson_number + "','" + lesson_name + "','" + teacher_number + "','" + teacher_name
                            + "','" + stu_num + "','" + stu_name + "')";
                    conn.setAutoCommit(false);
                    PreparedStatement preparedStatement = conn.prepareStatement(sql);
                    preparedStatement.executeUpdate();
                    conn.commit();
                    if ((a - count) == 1) {
                        sql = "update kecheng set status='-1' where name='" + lesson_name + "' ";
                        conn.setAutoCommit(false);
                        preparedStatement = conn.prepareStatement(sql);
                        preparedStatement.executeUpdate();
                        conn.commit();
                    }
                } else {
                    System.out.println("人数已达上限，不可选");
                }
            }
            else {
                System.out.println("与已选课冲突");
            }
        } catch (Exception e) {
            System.out.println(e.getMessage());
        } finally {
            if (conn != null) {
                conn.close();
            }
        }
    }

    // 返回课程详细信息
    public static void getLesson(String le_name, HttpServletRequest req) throws SQLException {

        String lesson_name = le_name;
        String lesson_number = null;
        String teacher_name = null;
        String teacher_number = null;
        Connection conn = null;
        Lesson les = new Lesson();
        int a = 0;
        int count = 0;
        try {

            String sql = "select * from kecheng where name='" + le_name + "' ";
            conn = DButil.getConn();
            // 连接对象coon调用createStatement()方法，创建一个执行SQL语句的对象st
            Statement st = conn.createStatement();
            // 执行SQL语句中的对象st调用executeQuery()方法，执行查询语句，将查询到的结果返回到一个结果集中
            ResultSet rs = st.executeQuery(sql);
            // 遍历结果集对象
            if (rs.next()) {
                lesson_number = rs.getString("number");
                teacher_name = rs.getString("teacher");
                a = rs.getInt("people");
            }

            sql = "select * from teacher where name='" + teacher_name + "' ";
            rs = st.executeQuery(sql);
            if (rs.next()) {
                teacher_number = rs.getString("num");
            }

            sql = "select * from chooseke where lesson_num='" + lesson_number + "' ";
            rs = st.executeQuery(sql);
            while (rs.next()) {
                count++;
            }
        } catch (Exception e) {
            System.out.println(e.getMessage());
        } finally {
            if (conn != null) {
                conn.close();
            }
        }

        les.setLesson_number(lesson_number);
        les.setLesson_name(lesson_name);
        les.setTeacher_number(teacher_number);
        les.setTeacher_name(teacher_name);
        les.setPe_num(count);
        les.setMessage(a);
        req.setAttribute("les", les);
    }

    // 返回老师对应的课程
    public static List<De> getTeacher_lesson(String name) throws SQLException {
        List<De> list = new ArrayList<De>();
        String sql = "select * from kecheng where teacher='" + name + "' ";
        Connection conn = DButil.getConn();
        try {
            // 连接对象coon调用createStatement()方法，创建一个执行SQL语句的对象st
            Statement st = conn.createStatement();
            // 执行SQL语句中的对象st调用executeQuery()方法，执行查询语句，将查询到的结果返回到一个结果集中
            ResultSet rs = st.executeQuery(sql);
            // 遍历结果集对象
            while (rs.next()) {
                De vol = new De();
                vol.setNumber(rs.getString("number"));
                vol.setName(rs.getString("name"));
                list.add(vol);
            }
        } catch (Exception e) {
            System.out.println(e.getMessage());
        } finally {
            if (conn != null) {
                conn.close();
            }
        }
        return list;
    }

    // 返回选择该课程学生的信息
    public static List<Student> getStu(String number) throws SQLException {
        List<Student> list = new ArrayList<Student>();
        String sql = "select * from chooseke where lesson_num= '" + number + "'";
        Connection conn = DButil.getConn();
        try {
            // 连接对象coon调用createStatement()方法，创建一个执行SQL语句的对象st
            Statement st = conn.createStatement();
            // 执行SQL语句中的对象st调用executeQuery()方法，执行查询语句，将查询到的结果返回到一个结果集中
            ResultSet rs = st.executeQuery(sql);
            // 遍历结果集对象
            while (rs.next()) {
                Student sd = new Student();
                sd.setName(rs.getString("stu_name"));
                sd.setNum(rs.getString("stu_number"));
                list.add(sd);
            }
        } catch (Exception e) {
            System.out.println(e.getMessage());
        } finally {
            if (conn != null) {
                conn.close();
            }
        }
        return list;
    }

    // 返回单个学生的详细信息
    public static Student get_Stu(String number) throws SQLException {
        Student sd = new Student();
        String sql = "select * from student where num= '" + number + "'";
        Connection conn = DButil.getConn();
        try {
            // 连接对象coon调用createStatement()方法，创建一个执行SQL语句的对象st
            Statement st = conn.createStatement();
            // 执行SQL语句中的对象st调用executeQuery()方法，执行查询语句，将查询到的结果返回到一个结果集中
            ResultSet rs = st.executeQuery(sql);
            // 遍历结果集对象
            if (rs.next()) {
                sd.setNum(rs.getString("num"));
                sd.setName(rs.getString("name"));
                sd.setSex(rs.getString("sex"));
                sd.setCla(rs.getString("class"));
                sd.setMajor(rs.getString("major"));
            }
        } catch (Exception e) {
            System.out.println(e.getMessage());
        } finally {
            if (conn != null) {
                conn.close();
            }
        }
        return sd;
    }

    /**
     * 删除数据
     */
    public static void delete(String stunumber) throws SQLException {
        String sql = "DELETE FROM STUMANAGE WHERE STUMANAGE.stunumber = '" + stunumber + "'";
        Connection conn = DButil.getConn();
        conn.setAutoCommit(false);
        PreparedStatement preparedStatement = conn.prepareStatement(sql);
        preparedStatement.executeUpdate();
        conn.commit();
        conn.close();
    }

    /**
     * 查找数据
     */
    public static void query() throws SQLException {
        String sql = "SELECT * FROM STUMANAGE";
        Connection conn = DButil.getConn();
        conn.setAutoCommit(false);
        PreparedStatement preparedStatement = conn.prepareStatement(sql);
        // 执行查询语句并返回结果集
        ResultSet resultSet = preparedStatement.executeQuery();
        while (resultSet.next()) {
            // 注意：这里要与数据库里的字段对应
            String stunumber = resultSet.getString("stunumber");
            String Code = resultSet.getString("code");
            System.out.println(stunumber + " " + Code);
        }
        conn.commit();
        conn.close();
    }

    /**
     * 查找特定数据
     */
    public static void query(String stu) throws SQLException {
        String sql = "SELECT * FROM STUMANAGE";
        Connection conn = DButil.getConn();
        conn.setAutoCommit(false);
        PreparedStatement preparedStatement = conn.prepareStatement(sql);
        // 执行查询语句并返回结果集
        ResultSet resultSet = preparedStatement.executeQuery();
        while (resultSet.next()) {
            // 注意：这里要与数据库里的字段对应
            String stunumber = resultSet.getString("stunumber");
            if (stu.contentEquals(stunumber)) {

            }
        }
        conn.commit();
        conn.close();
    }
}

通过这次的练习，自己的思维逻辑变得更清楚，对类的思想理解更为透彻，同时自己对jstl便签使用的也更加熟练，也认识到了el表达式的方便，但自己也发现了自己的好多问题，比如自己在上述代码中主要用的

是Statement，而不是PreparedStatement，这会有数据库漏洞，自己还发现在用MySQL数据库时，在一个函数中只能连接数据库一次，不可多次连接关闭，只能通过不断地SQL语句进行一系列操作，还有对于一些request中放置的attribute属性要注意其消亡时间。

自己的系统还有很多地方完善，自己对于web知识掌握还很浅显，自己还需要长期的努力。


原文链接:https://www.cnblogs.com/weixiao1717/p/12068630.html
如有疑问请与原作者联系

标签：

版权申明：本站文章部分自网络，如有侵权，请联系：west999com@outlook.com
特别注意：本站所有转载文章言论不代表本站观点，本站所提供的摄影照片，插画，设计作品，如需使用，请与原作者联系，版权归原作者所有

上一篇：js如何操作sass里的变量及calc 使用sass变量

下一篇：网页版面设计为什么无效

相关文章

IDC资讯： 主机资讯 注册资讯 托管资讯 vps资讯 网站建设

网站运营： 建站经验 策划盈利 搜索优化 网站推广 免费资源

网站联盟： 联盟新闻 联盟介绍 联盟点评 网赚技巧

行业资讯： 搜索引擎 网络游戏 电子商务 广告传媒

网络编程： Asp.Net编程 Asp编程 Php编程 Xml编程 Access Mssql Mysql 其它

服务器技术： Web服务器 Ftp服务器 Mail服务器 Dns服务器 安全防护

软件技巧： 其它软件 Word Excel Powerpoint Ghost Vista QQ空间 QQ FlashGet 迅雷

网页制作： FrontPages Dreamweaver Javascript css photoshop fireworks Flash

程序设计： Java技术 C/C++ VB delphi

网络知识： 网络协议 网络安全 网络管理 组网方案 Cisco技术

操作系统： Win2000 WinXP Win2003 Mac OS Linux FreeBSD

热门词条
最新资讯
热门关注
热门标签