选课系统1

import java.sql.*;
public class Classe_add 
{
    private String className;
    private String teacher;
    private String classSpace;
    public Classe_add( )
    {
        className="";
    }
    
    public String getClassName() {
        return className;
    }
    public void setClassName(String className) {
        this.className = className;
    }
    public String getTeacher() {
        return teacher;
    }
    public void setTeacher(String teacher) {
        this.teacher = teacher;
    }
    public String getClassSpace() {
        return classSpace;
    }
    public void setClassSpace(String classSpace) {
        this.classSpace = classSpace;
    }
    
    public Connection getConnection()
    {
        try{
            Class.forName("com.mysql.cj.jdbc.Driver");
            //System.out.println("加载驱动成功");
        }catch(ClassNotFoundException e)
        {
            e.printStackTrace();
        }
        String user="root";
        String password="woshinidie668";
        String url = "jdbc:mysql://localhost:3306/test?useSSL=false&serverTimezone=GMT&characterEncoding=utf-8&autoReconnect=true";
        Connection con=null;
        try{
            con=DriverManager.getConnection(url,user,password);
            //System.out.println("数据库连接成功");
        }catch(SQLException e)
        {
            e.printStackTrace();
        }
        return con;
    }
    public void addClass(String className,String teacher,String classSpace )
    {
        int judge=1;
        Connection connection = getConnection();
        String sql="select count(*) from grade where className = ?";
        
        PreparedStatement preparedStatement=null;
        ResultSet resultSet=null;
        
        try {
            preparedStatement=connection.prepareStatement(sql); 
            preparedStatement.setString(1,getClassName());
            
            resultSet = preparedStatement.executeQuery();
            while(resultSet.next()) 
            {
                if (resultSet.getInt(1) > 0) 
                {
                    System.out.println("课程已存在,无法添加") ;
                    judge=0;
                }
            }
            if(judge==1)
            {  
                sql = "insert into grade (curriculum,teacher,place) values (?,?,?)";
                preparedStatement=connection.prepareStatement(sql);
                preparedStatement.setString(1,className);
                preparedStatement.setString(2,teacher);
                preparedStatement.setString(3,classSpace);
                preparedStatement.executeUpdate();
                System.out.println("添加成功") ;
            }
        } catch (SQLException  e) 
        {
            e.printStackTrace();
        }
        finally
        {
            close(resultSet);
            close(preparedStatement);
            close(connection);
        }
    }
    
    public  void close (Connection con)
    {
        try{
            if(con!=null)
            {
                con.close();
            }
        }catch(SQLException e)
            {
                e.printStackTrace();
            }
    }
    public  void close (PreparedStatement preparedStatement)
    {
        try{
            if(preparedStatement!=null)
            {
                preparedStatement.close();
            }
        }catch(SQLException e)
        {
            e.printStackTrace();
        }
    }
    public  void close(ResultSet resultSet)
    {
        try{
            if(resultSet!=null)
            {
                resultSet.close();
            }
        }catch(SQLException e)
        {
            e.printStackTrace();
        }
    }
    public boolean judgeInputNull(String className,String teacher,String classSpace)
    {
        boolean flag=false;
        if(className==null||"".equals(className)&&teacher==null||"".equals(teacher)&&classSpace==null||"".equals(classSpace))
        {
            flag=true;
        }
        return flag;
    }
    public boolean judgeClassRepeat(String className,String teacher,String classSpace)
    {
        boolean flag=false;
        
        Connection connection = getConnection();
        String sql="select count(*) from grade where teacher = ?";    
        
        PreparedStatement preparedStatement=null;
        ResultSet resultSet=null;
        try {
            preparedStatement=connection.prepareStatement(sql);    
            preparedStatement.setString(1,className);
            resultSet = preparedStatement.executeQuery();
            while(resultSet.next()) 
            {                
                
                if(teacher.equals(resultSet.getString("teacher"))&&classSpace.equals(resultSet.getString("place")))
                {
                    flag=true;
                }
                
            }
        }catch (SQLException e) {
            e.printStackTrace();
        }finally {
            close(resultSet);
            close(preparedStatement);
            close(connection);
        }
        return  flag;
    }
    
    public boolean judeInputTeacher(String teacher)
    {
        boolean flag=false;
        if((!teacher.equals("王建民"))&&!teacher.equals("刘立嘉")&&!teacher.equals("刘丹")&&!teacher.equals("王辉")&&!teacher.equals("杨子光"))
        {
            flag=true;
        }
       
        return flag;
    }
    public boolean judgeInputClassSpace(String space)
    {
        boolean flag=false;
        if(!space.startsWith("一教")&&!space.startsWith("二教")&&!space.startsWith("三教")&&!space.startsWith("基教"))
        {
            flag=true;
        }
        return flag;
    }
    public static void main(String[] args)
    {
       Classe_add a=new Classe_add();        
       a.judgeClassRepeat("软件工程", "王建民", "基教402");
       //a.addClass("软件工程","王建民","基教402");
       
    }
}