Use JDBC technology and MySQL database management system to realize the function of course management, including adding, modifying, querying and deleting course information.

package Mooc;

import com.mysql.jdbc.PreparedStatement;

import java.sql.*;
import java.util.LinkedList;
import java.util.List;
import java.util.Scanner;

// Course DAO Interface 
interface ICourseDao {
    public int insert(Course course) throws Exception;
    public int delete(int id) throws Exception;
    public int update(Course course) throws Exception;
    public List<Course> select() throws Exception;
}

// Database connection utility class 
class DBConnection {
    //  Get database connection 
    public static Connection getConnection() throws SQLException {
        // Your implementation code 
        Connection con= DriverManager.getConnection("jdbc:mysql://localhost:3306/course","root","admin");
        return con;
    }
    //  Close the database resource 
    public static void close(ResultSet rs, PreparedStatement pstmt, Connection conn) throws Exception {
        // Your implementation code 
        rs.close();
        pstmt.close();
        conn.close();
    }
    //  Close the database resource 
    public static void close(PreparedStatement pstmt, Connection conn) throws Exception {
        // Your implementation code 
        pstmt.close();
        conn.close();
    }
}

//  Course entity class 
class Course {
// Your implementation code 
    private int id;
    private String name;
    private double mark;

    public int getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public void setId(int id) {
        this.id = id;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getMark() {
        return mark;
    }

    public void setMark(double mark) {
        this.mark = mark;
    }
}

// Course  DAO Implementation class , Be responsible for the specific implementation of database access operation 
class CourseDaoImpl implements ICourseDao {
    private static final String SQL_INSERT = "insert into course (name,mark) values(?,?)";
    private static final String SQL_DELETE = "delete from course where id=?";
    private static final String SQL_UPDATE = "update course set name=?,mark=? where id=?";

    public int insert(Course course) throws Exception {
        return update(SQL_INSERT, new Object[] { course.getName(), course.getMark(), });
    }

    public int delete(int i) throws Exception {
        return update(SQL_DELETE, new Object[] { i });
    }

    public int update(Course course) throws Exception {
        return update(SQL_UPDATE, new Object[] { course.getName(), course.getMark(), course.getId() });
    }
    // Query all course information in the table and return it in the form of a list 
    public List<Course> select() throws Exception {
        List<Course> courseList = null;
        // Your implementation code 
        courseList=new LinkedList<>();
        Connection con=DBConnection.getConnection();
        Statement stat=con.createStatement();
        ResultSet rs=stat.executeQuery("select * from course");
        while (rs.next()){
            Course c=new Course();
            c.setId(rs.getInt(1));
            c.setName(rs.getString(2));
            c.setMark(rs.getDouble(3));
            courseList.add(c);
        }
        return  courseList;
    }
    // Realize the increase of course information 、 Modification and deletion 
    public int update(String sql, Object[] params) throws Exception {
        int flag = 0;
        Connection conn = null;
        PreparedStatement pstmt = null;
        // Your implementation code 
        conn=DBConnection.getConnection();
        pstmt= (PreparedStatement) conn.prepareStatement(sql);
        for(int i=0;i<params.length;i++){
            pstmt.setObject(i+1,params[i]);
        }
        pstmt.executeUpdate();
        pstmt.close();
        conn.close();
        return params.length;
    }
}
// Test the query of course information separately 、 Increase 、 Modify and delete functions 
 class Main {
    public static void main(String[] args) throws Exception {
        // Your implementation code 
        Scanner sc=new Scanner(System.in);
        CourseDaoImpl c=new CourseDaoImpl();
        List<Course>courseList=c.select();
        System.out.println("course Available data ：");
        for(Course i:courseList){
            System.out.println(i.getId()+" "+i.getName()+" "+i.getMark());
        }
        System.out.println("------------------------");

        System.out.println(" Please enter the operation you want to perform :\n");
        System.out.println("1-- increase \n2-- Inquire about \n3-- modify \n4-- Delete \n0-- sign out ");
        int n=sc.nextInt();
        while(n!=0){
            switch (n){
                case 1:{
                    Course co=new Course();
                    System.out.println(" Please enter name ：");
                    String sn=sc.next();
                    co.setName(sn);
                    System.out.println(" Please enter credits ：");
                    Double sm=sc.nextDouble();
                    co.setMark(sm);
                    c.insert(co);
                    System.out.println(" Increase success ");
                    break;
                }
                case 2:{
                    System.out.println(" Please enter ID:");
                    int k=sc.nextInt();
                    int f=0;
                    for(Course i:courseList){
                        if(i.getId()==k){
                            System.out.println(i.getId()+" "+i.getName()+" "+i.getMark());
                            f=1;
                            System.out.println(" The query is successful ");
                            break;
                        }
                    }if(f==0)
                        System.out.println(" The result is empty. ");
                    break;
                }
                case 3:{
                    System.out.println(" Please enter to be modified ID：");
                    Course ce=new Course();
                    int s1=sc.nextInt();
                    ce.setId(s1);
                    System.out.println(" Please enter name ：");
                    String s2=sc.next();
                    ce.setName(s2);
                    System.out.println(" Please enter credits ：");
                    ce.setMark(sc.nextDouble());
                    c.update(ce);
                    System.out.println(" Modification successful ");
                    break;
                }
                case 4:{
                    System.out.println(" Please enter the... To be deleted ID：");
                    c.delete(sc.nextInt());
                    System.out.println(" Delete successful ");
                    break;
                }
                default:
                    System.out.println("error");
            }

        }
    }
}