Java实验2-数据库编程

目标：掌握Java数据库编程

内容：

学生选课系统包括如下数据库表

• 学生表：Student(Sno，Sname，Ssex，Sage，Sdept)
• 课程表：Course(Cno，Cname，Ccredit)
• 学生选课表：SC(Sno，Cno，Grade)

在课堂上，老师以学生管理功能为例用Java实现了对学生记录的增、删、改、查操作。请仿照此例，用Java实现对课程和学生选课记录的增、删、改、查操作。

程序实现代码：

Course.java;

CourseManger.java;

CourseTableCreator.java;

DatabaseManager.java;

Student.java;

StudentManager.java;

StudentTableCreator.java;

SelectCourse.java;

SelectCourseManager.java;

scTableCreator.java

代码1：Course.java

public class Course {
    
       private   int      Cno;
       private   String   Cname;
       private   int      Ccredit;
       
       public void setNo(int Cno){
           this.Cno = Cno;
       }
       public void setName(String Cname){
           this.Cname = Cname;
       }
       public void setCredit(int Ccredit){
           this.Ccredit = Ccredit;
       }
       
       public int getNo(){
           return Cno;
       }
       public String getName(){
           return Cname;
       }
       public int getCredit(){
           return Ccredit;
       }
       public String toString(){
           return "Cno: "+Cno+"	Cname: "+Cname+"	Ccredit: "+Ccredit;
       }
}

代码2：CourseManager.java

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

public class CourseManager {
        private Connection cn ;
        private Statement stmt;
        private PreparedStatement prepStmt;
        
        public CourseManager(){
            cn = new DatabaseManager().openConnection();
        }
        
        public void addCourse(Course course){
              try{
                  if(cn!=null){
                      String query = "insert into course(Cno ,Cname ,Ccredit ) values(? ,? ,? )";
                      prepStmt = cn.prepareStatement(query);
                      prepStmt.setInt(1 ,course.getNo());
                      prepStmt.setString(2 ,course.getName());
                      prepStmt.setInt(3 ,course.getCredit());
                      prepStmt.executeUpdate();
                  }
              } catch (Exception e){
                  System.out.println("create CourseManager error:"+e);
              }
        }
        
        public void  deleteCourse(Course course){
               try{
                   if(cn!=null){
                      String query = "delete form course where Cno =?";
                      prepStmt = cn.prepareStatement(query);
                      prepStmt.setInt(1 ,course.getNo());
                      prepStmt.executeUpdate();
                   }
               } catch (Exception e){
                   System.out.println("delet course error:"+e);
               }
        }
        
        public void updateCourse(Course course){
            try{
                if(cn!= null){
                    String query = "update course set Cno=?,Cname=?,Ccredit=? ";
                    prepStmt = cn.prepareStatement(query);
                    prepStmt.setInt(1 ,course.getNo());
                    prepStmt.setString(2 ,course.getName());
                    prepStmt.setInt(3 ,course.getCredit());
                    prepStmt.executeUpdate();
                }
            }catch (Exception e){
                System.out.println("update course error:"+e);
            }
        }
        
        public ArrayList<Course> queryCourse(){
               ArrayList<Course> courses = new ArrayList<Course>();
               Course course;
               try{
                   if(cn!=null){
                       stmt = cn.createStatement();
                       ResultSet rs = stmt.executeQuery("SELECT * FROM course");
                       while(rs.next()){
                           course = new Course();
                           course.setNo(rs.getInt("Cno"));
                           course.setName(rs.getString("Cname"));
                           course.setCredit(rs.getInt("Ccredit"));
                           courses.add(course);
                       }
                   }
               } catch (Exception e){
                   System.out.println("query course error:"+e);
               }
               return courses;
        }
        public void closeConnection(){
            try{
                stmt.close();
                prepStmt.close();
                cn.close();
            } catch (Exception e){
                System.out.println("close connection error:"+e);
            }
        }
}

代码3：CourseTableCreator.java

import java.sql.*;

public class CourseTableCreator {
    private Connection cn;
    private Statement stmt;
    private PreparedStatement prepStmt;

    public CourseTableCreator() {
        cn = new DatabaseManager().openConnection();
    }

    public void dropTable() {
        try {
            if (cn != null) {
                stmt = cn.createStatement();
                String qurey = "drop table course";
                stmt.execute(qurey);
                System.out.println("drop table course");
            }
        } catch (Exception e) {
            System.out.println("drop table course error:" + e);
        }
    }

    public void createTable() {
        try {
            if (cn != null) {
                String qurey = "create table course(Cno int PRIMARY KEY,Cname varchar(20),Ccredit int)";
                stmt = cn.createStatement();
                stmt.execute(qurey);
                System.out.println("create table course");
            }
        } catch (Exception e) {
            System.out.println("create table course error: " + e);
        }
    }

    public void insertIntRecords() {
        try {
            if (cn != null) {
                String query = "insert into course(Cno ,Cname ,Ccredit) values(?, ?, ?)";
                prepStmt = cn.prepareStatement(query);
                prepStmt.setInt(1, 1001);
                prepStmt.setString(2, "高等数学");
                prepStmt.setInt(3, 6);
                prepStmt.executeUpdate();

                prepStmt.setInt(1, 1002);
                prepStmt.setString(2, "java程序设计");
                prepStmt.setInt(3, 3);
                prepStmt.executeUpdate();

                prepStmt.setInt(1, 1003);
                prepStmt.setString(2, "通信原理");
                prepStmt.setInt(3, 5);
                prepStmt.executeUpdate();

                prepStmt.setInt(1, 1004);
                prepStmt.setString(2, "DSP 原理及其应用");
                prepStmt.setInt(3, 3);
                prepStmt.executeUpdate();

                System.out.println("4 course records has been inserted");
            }
        } catch (Exception e) {
            System.out.println("create table course error:" + e);
        }
    }

    public void closeConnection() {
        try {
            stmt.close();
            prepStmt.close();
            cn.close();
        } catch (Exception e) {
            System.out.println("table course close conncetion error:" + e);
        }
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        CourseTableCreator creator = new CourseTableCreator();
        creator.dropTable();
        creator.createTable();
        creator.insertIntRecords();
        creator.closeConnection();
    }

}

代码4：DatabaseManager.java

import java.sql.DriverManager;
import java.sql.Connection;

public class DatabaseManager {    
    private Connection cn;
    public  Connection  openConnection() {
        try{
            Class.forName("com.mysql.jdbc.Driver"); 
            String url = "jdbc:mysql://localhost:3306/javaCourse";
            cn=DriverManager.getConnection(url, "root", "manager"); 
            
        }catch(Exception e){
            System.out.println("open databse connection error:"+e);
        }

        return cn;
    }
    public void closeConnection(){
        try{
            cn.close();
        }catch (Exception e){
            System.out.println("close databse connection error:"+e);
        }
    }

} 
SelectCourse.java的源代码如下：
public class SelectCourse {
    private  int  Sno;
    private  int  Cno;
    private  int  Grade;
    
    public void setStudentNo(int Sno){
        this.Sno = Sno;
    }
    public int getStudentNo(){
        return Sno;
    }
    public void setCourseNo(int Cno){
        this.Cno = Cno;
    }
    public int getCourseNo(){
        return Cno;
    }
    public void setGrade(int Grade){
        this.Grade = Grade;
    }
    public int getGrade(){
        return Grade;
    }
}

代码5：SelectCourseManager.java

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

public class SelectCourseManager {
        private Connection cn;
        private Statement  stmt;
        private PreparedStatement prepStmt;
        
        public SelectCourseManager(){
            cn = new DatabaseManager().openConnection();
        }
        
        public void addRecord(SelectCourse sc){
            try{
                if(cn!= null){
                    String query = "insert into selectCourse(Sno ,Cno ,Grade) values(? ,? ,?)";
                    prepStmt = cn.prepareStatement(query);
                    prepStmt.setInt(1 , sc.getStudentNo());
                    prepStmt.setInt(2 , sc.getCourseNo());
                    prepStmt.setInt(3 , sc.getGrade());
                    prepStmt.executeUpdate();
                }
            }catch (Exception e){
                System.out.println("add one record to  selectCoursee error:"+e);
            }
        }
        public void deleteRecord(SelectCourse sc){
            try{
                if(cn!= null){
                    String qurey = "delete from  selectCourse where Sno=?";
                    prepStmt = cn.prepareStatement(qurey);
                    prepStmt.setInt(1 , sc.getStudentNo());
                    prepStmt.executeUpdate();
                }
            }catch (Exception e){
                System.out.println("delete one record from  selectCourse error:"+e);
            }
        }
        
        public void updateRecord(SelectCourse sc){
            try{
                if(cn!=null){
                    String qurey = "update  selectCourse Cno=?,Grade=? where Sno=?";
                    prepStmt = cn.prepareStatement(qurey);
                    prepStmt.setInt(1 , sc.getCourseNo());
                    prepStmt.setInt(2 , sc.getGrade());
                    prepStmt.setInt(3 , sc.getStudentNo());
                    prepStmt.executeUpdate();    
                }
            }catch(Exception e){
                System.out.println("update record form  selectCourse error: "+e);
            }
        }
        public  ArrayList <SelectCourse> queryRecord(){
            ArrayList <SelectCourse> scs = new ArrayList<SelectCourse>();
            SelectCourse sc;
            try {
                if(cn!=null){
                    stmt = cn.createStatement();
                    ResultSet rs= stmt.executeQuery("SELECT * FROM  selectCourse");
                    while(rs.next()){
                        sc = new SelectCourse();
                        sc.setStudentNo(rs.getInt("Sno"));
                        sc.setCourseNo(rs.getInt("Cno"));
                        sc.setGrade(rs.getInt("Grade"));
                        scs.add(sc);
                    }
                }
            }catch(Exception e){
                System.out.println("query  selectCourse error: "+e);
            }
            return scs;
        }
        public void closeConnection(){
            try{
                stmt.close();
                prepStmt.close();
                cn.close();
            }catch (Exception e){
                System.out.println("close connection of  selectCourse error:"+e);
            }
        }
}

代码6：scTableCreator.java

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.Statement;

public class scTableCreator {
    private    Connection  cn;
    private    Statement   stmt;
    private    PreparedStatement   prepStmt;
    
    public scTableCreator(){
        cn = new DatabaseManager().openConnection();
    }
    
    public void dropTalbe(){
        try{
            if(cn!=null){;
                stmt = cn.createStatement();
                stmt.execute("drop table selectCourse");
                System.out.println("drop table selectCourse!");
            }
        }catch (Exception e){
            System.out.println("drop table selectCourse error:"+e);
        }
    }
    public void createTable(){
        try{
            if(cn!=null){
                stmt = cn.createStatement();
                stmt.execute("create table selectCourse(Sno int ,Cno int ,Grade int,foreign key(Sno) references Student(Sno),foreign key(Cno) references Course(Cno))");
                System.out.println("create table selectCourse");
            }
        }catch (Exception e){
            System.out.println("create table selectCourse error:"+e);
        }
    }

    public void insertInitRecords() {
        try {
            if (cn != null) {
                String query = "insert into selectCourse(Sno ,Cno ,Grade ) values(? ,? ,?)";
                prepStmt = cn.prepareStatement(query);
                prepStmt.setInt(1, 20092725);
                prepStmt.setInt(2, 1001);
                prepStmt.setInt(3, 90);
                prepStmt.executeUpdate();

                prepStmt.setInt(1, 20092725);
                prepStmt.setInt(2, 1002);
                prepStmt.setInt(3, 96);
                prepStmt.executeUpdate();

                prepStmt.setInt(1, 20092740);
                prepStmt.setInt(2, 1004);
                prepStmt.setInt(3, 100);
                prepStmt.executeUpdate();

                System.out.println("some records added to selectCourse");

            }
        } catch (Exception e) {
            System.out
                    .println("inset inital records to table selectCourse error:"
                            + e);
        }
    }
    public void closeConneciton(){
        try{
            stmt.close();
            prepStmt.close();
            cn.close();
        } catch (Exception e){
        System.out.println("close connection of selectCourse error:"+e);
        }
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
            scTableCreator creator = new scTableCreator();
            creator.dropTalbe();
            creator.createTable();
            creator.insertInitRecords();
            creator.closeConneciton();
    }

} 

代码7：Student.java

public class Student {
        //fileds of student 
        private  int      Sno;
        private  String   Sname;
        private  String   Ssex;
        private  int      Sage;
        private  String   Sdept;
        
        //Methods of student
        public int getNo(){
            return Sno;
        }
        public String getName(){
            return Sname;
        }
        public String getSex(){
            return Ssex;
        }
        public int getAge(){
            return Sage;
        }
        public String getDept(){
            return Sdept;
        }
        public void setNo(int Sno){
            this.Sno = Sno;
        }

        public void setName(String Sname){
            this.Sname = Sname;
        }
        public void setSex(String Ssex){
            this.Ssex = Ssex;
        }
        public void setAge(int Sage){
            this.Sage = Sage;
        }
        public void setDept(String Sdept){
            this.Sdept = Sdept;
        }
        public String toString(){
            return Sno+"    "+Sname+"    "+Ssex+"   "+Sage+"    "+Sdept;
        }
}

代码8：StudentManager.java

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

public class StudentManager {
        private   Connection cn;
        private   Statement stmt;
        private   PreparedStatement prepStmt;
        
        public StudentManager(){
            cn = new DatabaseManager().openConnection();
        }
        
        public void addStudent(Student student){
            try{
                if(cn!=null){
                    String query = "insert into student(Sno ,Sname ,Ssex ,Sage ,Sdept) values(? ,? ,? ,? ,? )";
                    prepStmt = cn.prepareStatement(query);  //create a statement here
                    prepStmt.setInt(1 ,student.getNo());
                    prepStmt.setString(2 ,student.getName());
                    prepStmt.setString(3 ,student.getSex());
                    prepStmt.setInt(4 ,student.getAge());
                    prepStmt.setString(5 ,student.getDept());
                    prepStmt.executeUpdate();
                }
            } catch (Exception e){
                System.out.println("add one student error!");
                e.printStackTrace();
            }
            
        }
        
        public void deleteStudent(Student student){
            try{
                if(cn!=null){
                    String query = "delete from student where Sno = ?";
                    prepStmt = cn.prepareStatement(query);
                    prepStmt.setInt(1 ,student.getNo());
                    prepStmt.executeUpdate();
                } 
            }catch (Exception e){
                System.out.print("delete student error"+e);
            }
        }
        
        public void updateStudent(Student student){
            try{
                if(cn!= null){
                    String query = "update student set Sname=?, Ssex=? ,Ssex=?,Sdept = ?"+"where Sno=?";
                    prepStmt = cn.prepareStatement(query);
                    prepStmt.setString(1 ,student.getName());
                    prepStmt.setString(2 ,student.getSex());
                    prepStmt.setInt(3 ,student.getAge());
                    prepStmt.setString(4 ,student.getDept());
                    prepStmt.setInt(5 ,student.getNo());
                    prepStmt.executeUpdate();
                }
            } catch (Exception e){
                System.out.println("update student error:"+e);
            }
        }
        
        public ArrayList<Student> queryStudent(){
               ArrayList<Student> students = new ArrayList<Student>();
               Student student;
               
               try{
                   if(cn!=null){
                       stmt = cn.createStatement();
                       ResultSet rs = stmt.executeQuery("SELECT * FROM student") ;
                       while(rs.next()){
                           student = new Student();
                           student.setNo(rs.getInt("Sno"));
                           student.setName(rs.getString("Sname"));
                           student.setSex(rs.getString("Ssex"));
                           student.setAge(rs.getInt("Sage"));
                           student.setDept(rs.getString("Sdept"));
                           students.add(student);
                       }
                   } 
               }catch (Exception e){
                   System.out.println("query student error:"+e);
               }
               return students;
        }
        
        public void closeConnection(){
            try{
                prepStmt.close();
                stmt.close();
                cn.close();
            } catch (Exception e) {
                System.out.println("close connection error:"+e);
            }
        }
}

代码9：StudentTableCreator.java

import java.util.ArrayList;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.Statement;

public class StudentTableCreator {
    private    Connection  cn;
    private    Statement   stmt;
    private    PreparedStatement   prepStmt;
    
    public  StudentTableCreator(){
        cn = new DatabaseManager().openConnection();
    }
    
    public  void dropTable(){
        try{
            if(cn!=null){
                stmt = cn.createStatement();
                stmt.execute("drop table student");
                System.out.println("drop table student");
            }
        }catch (Exception e){
            System.out.println("drop table student error:"+e);
        }
    }
    public void createTable(){
        try{
            if(cn!=null){
                stmt = cn.createStatement();
                stmt.execute("create table student(Sno int PRIMARY KEY,Sname varchar(18),Ssex varchar(4),Sage tinyint,Sdept varchar(20))");
                System.out.println("table student created!");
            }
        }catch (Exception e){
            System.out.println("create table student error:"+e);
        }
    }
    
    public void inserInitRecords(){
        try{
            if(cn!=null){
                String query = "insert into student(Sno,Sname,Ssex,Sage,Sdept) values(?,?,?,?,?)";
                prepStmt = cn.prepareStatement(query);
                prepStmt.setInt(1 ,20092725);
                prepStmt.setString(2 ,"张三");
                prepStmt.setString(3 ,"男");
                prepStmt.setInt(4 , 22);
                prepStmt.setString(5 ,"信息学院");
                prepStmt.executeUpdate(); 
                
                prepStmt.setInt(1 ,20092740);
                prepStmt.setString(2 ,"李四");
                prepStmt.setString(3 ,"男");
                prepStmt.setInt(4 ,23);
                prepStmt.setString(5 ,"信息学院");
                prepStmt.executeUpdate(); 
                
                prepStmt.setInt(1 ,20092899);
                prepStmt.setString(2 ,"王五");
                prepStmt.setString(3, "男");
                prepStmt.setInt(4 , 22);
                prepStmt.setString(5 ,"材冶学院");
                prepStmt.executeUpdate(); 
                
                prepStmt.setInt(1 ,20093506);
                prepStmt.setString(2 ,"赵六");
                prepStmt.setString(3, "女");
                prepStmt.setInt(4 ,21);
                prepStmt.setString(5 , "工管学院");
                prepStmt.executeUpdate(); 
                
                prepStmt.setInt(1 , 20101105);
                prepStmt.setString(2 , "刘七");
                prepStmt.setString(3 , "男");
                prepStmt.setInt(4 ,20);
                prepStmt.setString(5 ,"软件学院");
                prepStmt.executeUpdate(); 
                
                System.out.println("Insert 5 records");
            }
        }catch (Exception e){
            System.out.println("insert records error :"+e);
        }
    }
    public void closeConnection(){
         try{
             prepStmt.close();
             stmt.close();
             cn.close();
             System.out.println("student table creator connection !");
         }catch (Exception e){
             System.out.println(" student table close connection error:"+e);
         }
    }
    public static void main(String[] args){
        ArrayList<Student> s = new ArrayList<Student>();
        StudentTableCreator creator = new StudentTableCreator();
        creator.dropTable();
        creator.createTable();
        creator.inserInitRecords();
        StudentManager sm = new StudentManager();
        s = sm.queryStudent();
        System.out.print(s);
        creator.closeConnection();
    }
}

数据库使用：mysql，驱动使用
运行结果：