Main.java

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Scanner;

import com.mysql.jdbc.Statement;
public class Main {

	/**
	 * @param args
	 * @throws ClassNotFoundException 
	 * @throws SQLException 
	 */

	public static void main(String[] args) throws Exception {
		
		Scanner keyboardInput = new Scanner(System.in);
		System.out.println("=========== MENU ===========");
		System.out.println("1.) Register");
		System.out.println("2.) Login");
		System.out.print("Enter Choice: ");

		try{
			int choiceKeyboard = keyboardInput.nextInt();
			if (choiceKeyboard==1){
				insertMember();
				main(args);
			}else if (choiceKeyboard==2){
				login();
			}else {
				System.out.println("Please select 1 or 2.");
				main(args);
			}
		}catch(Exception e){
			System.out.println("Please select 1 or 2.");
			main(args);
		}
	}
	
	public static void login() throws ClassNotFoundException, SQLException {
		Class.forName("com.mysql.jdbc.Driver");
		Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/DataBase","root","");
		
		System.out.println("\n=========== Input information ===========");
		Scanner keyboardInput = new Scanner(System.in);
		System.out.print("     Enter Login Name: ");
		String nameInput = keyboardInput.nextLine();
		
		PreparedStatement statement = con.prepareStatement("SELECT * from user WHERE USER_FNAME = '" + nameInput + "'");
		ResultSet result = statement.executeQuery();
		String USER_ID = null;
		
		if(result.next()){
			USER_ID = result.getString(3);
			System.out.print("     Enter Login Password: ");
			String surnameInput = keyboardInput.nextLine();
			
			if(surnameInput.equals(result.getString(3))){
				System.out.println("\nWelcome to enrollment system.\n");
				USER_ID = result.getString(1);
				int USER_ID_INT = Integer.parseInt(USER_ID);
				menuUser(USER_ID_INT);
			}else{
				System.out.println("Sorry, your password is wrong! Please login again.");
				login();
			}		
		}else{
			System.out.println("Sorry, system has no this account! please login again");
			login();
		}	
	}
	
	public static void examTable(int userID) throws SQLException{
		
		try {
			Class.forName("com.mysql.jdbc.Driver");
			Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/DataBase","root","");
			PreparedStatement statement = con.prepareStatement("SELECT * from course WHERE USER_ID = " + userID + "");
			ResultSet result = statement.executeQuery();
			
			System.out.println("\n========== Examination Table ==========");
			System.out.println("Course ID     " + "Course Name       " + "Course Time");
			while (result.next()){				
				System.out.println(result.getString(1) + "       " +result.getString(3)+ "\t\t" +result.getString(2));	
			}
			menuUser(userID);
		} catch (ClassNotFoundException e) {
			e.printStackTrace();
		}	
	}
	
	public static void menuUser(int USER_ID_INT){
		System.out.println("\n=========== MENU ===========");
		System.out.println("Select 1 for course enrollment");
		System.out.println("Select 2 for knowing exam table");
		System.out.println("Select 3 for exit");
		System.out.print("Enter your selection: ");
		
		try{
			Scanner keyboardInput = new Scanner(System.in);
			int choiceInput = keyboardInput.nextInt();

			if (choiceInput==1){
				insertCourse(USER_ID_INT);
			}else if (choiceInput==2){
				examTable(USER_ID_INT);
			}else if (choiceInput==3){
				System.out.print("Good bye!");
			}else{
				System.out.println("Please select 1 or 2. Please login again");
				menuUser(USER_ID_INT);
			}
		}catch(Exception e){
			System.out.println("Please select 1 or 2. Please choose again");
			menuUser(USER_ID_INT);
		}
	}
	
	public static void insertCourse(int userID) throws ClassNotFoundException, SQLException{
		Class.forName("com.mysql.jdbc.Driver");
		Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/DataBase","root","");
		PreparedStatement statement = con.prepareStatement("SELECT * from courselist");
		ResultSet result = statement.executeQuery();
		
		int counter = 0;
		while (result.next()){	
			counter++;
			System.out.println(counter + ".) Course ID: " + result.getString(1) + " \tCourse Name: " +result.getString(2)+ " \tCourse Time: " +result.getString(3)+ " \tCourse Examination Date: " +result.getString(4));	
		}
		
		Scanner inputCourse = new Scanner(System.in);
		System.out.print("\nEnter course you want to enroll(input 0 to exit to menu): ");
		
		try{
			int input = inputCourse.nextInt();
			PreparedStatement statementCourse = null;
			if(input==1){
				PreparedStatement checkCourseStatement = con.prepareStatement("SELECT * from course WHERE C_ID='1302001' AND USER_ID= '" + userID + "'");
				ResultSet resultCheckCourseStatement = checkCourseStatement.executeQuery();
				int count = 0;
				while(resultCheckCourseStatement.next()){
					count++;
				}
				
				if(count==0){
					statementCourse = con.prepareStatement("SELECT * from courselist WHERE C_ID= '" + 1302001 + "'");
					ResultSet resultCourse = statementCourse.executeQuery();
					
					String C_ID = null, C_Sub = null, C_Time = null, C_Exam = null; 
					while (resultCourse.next()){	
						C_ID = resultCourse.getString(1);
						C_Sub = resultCourse.getString(2);
						C_Time = resultCourse.getString(3);
						C_Exam = resultCourse.getString(4);	
					}
					
					String query = " insert into course (C_ID, C_Time, C_Sub, USER_ID)" + " values (?, ?, ?, ?)";
						
					PreparedStatement preparedStmt = con.prepareStatement(query);
					preparedStmt.setString (1, C_ID);
					preparedStmt.setString (2, C_Time);
					preparedStmt.setString (3, C_Sub);
					preparedStmt.setInt (4, userID);
					preparedStmt.execute();
					
					String query1 = " insert into examination (USER_ID, E_ID, E_Sub, E_Time)" + " values (?, ?, ?, ?)";
						
					PreparedStatement preparedStmt1 = con.prepareStatement(query1);
					preparedStmt1.setInt (1, userID);
					preparedStmt1.setString (2, C_ID);
					preparedStmt1.setString (3, C_Sub);
					preparedStmt1.setString (4, C_Exam);
					preparedStmt1.execute();
					
					System.out.print("Enrollment is success!\n");
					menuUser(userID);
				}else{
					System.out.println("\nYou used to register this course.\n");
					insertCourse(userID);
				}
			}else if (input==2){

				PreparedStatement checkCourseStatement = con.prepareStatement("SELECT * from course WHERE C_ID='1302002' AND USER_ID= '" + userID + "'");
				ResultSet resultCheckCourseStatement = checkCourseStatement.executeQuery();
				int count = 0;
				while(resultCheckCourseStatement.next()){
					count++;
				}

				if(count==0){
					statementCourse = con.prepareStatement("SELECT * from courselist WHERE C_ID= '" + 1302002 + "'");
					ResultSet resultCourse = statementCourse.executeQuery();
					
					String C_ID = null, C_Sub = null, C_Time = null, C_Exam = null; 
					while (resultCourse.next()){	
						C_ID = resultCourse.getString(1);
						C_Sub = resultCourse.getString(2);
						C_Time = resultCourse.getString(3);
						C_Exam = resultCourse.getString(4);
						
					}
					
					String query = " insert into course (C_ID, C_Time, C_Sub, USER_ID)" + " values (?, ?, ?, ?)";
						
					PreparedStatement preparedStmt = con.prepareStatement(query);
					preparedStmt.setString (1, C_ID);
					preparedStmt.setString (2, C_Time);
					preparedStmt.setString (3, C_Sub);
					preparedStmt.setInt (4, userID);
					preparedStmt.execute();
					
					String query1 = " insert into examination (USER_ID, E_ID, E_Sub, E_Time)" + " values (?, ?, ?, ?)";
						
					PreparedStatement preparedStmt1 = con.prepareStatement(query1);
					preparedStmt1.setInt (1, userID);
					preparedStmt1.setString (2, C_ID);
					preparedStmt1.setString (3, C_Sub);
					preparedStmt1.setString (4, C_Exam);
					preparedStmt1.execute();
					System.out.print("Enrollment is success!\n");
					menuUser(userID);
				}else{
					System.out.println("\nYou used to register this course.\n");
					insertCourse(userID);
				}

			}else if (input==3){

				PreparedStatement checkCourseStatement = con.prepareStatement("SELECT * from course WHERE C_ID='1302003' AND USER_ID= '" + userID + "'");
				ResultSet resultCheckCourseStatement = checkCourseStatement.executeQuery();
				int count = 0;
				while(resultCheckCourseStatement.next()){
					count++;
				}

				if(count==0){
					statementCourse = con.prepareStatement("SELECT * from courselist WHERE C_ID= '" + 1302003 + "'");
					ResultSet resultCourse = statementCourse.executeQuery();
					
					String C_ID = null, C_Sub = null, C_Time = null, C_Exam = null; 
					while (resultCourse.next()){	
						C_ID = resultCourse.getString(1);
						C_Sub = resultCourse.getString(2);
						C_Time = resultCourse.getString(3);
						C_Exam = resultCourse.getString(4);
						
					}
					
					String query = " insert into course (C_ID, C_Time, C_Sub, USER_ID)"+ " values (?, ?, ?, ?)";
						
					PreparedStatement preparedStmt = con.prepareStatement(query);
					preparedStmt.setString (1, C_ID);
					preparedStmt.setString (2, C_Time);
					preparedStmt.setString (3, C_Sub);
					preparedStmt.setInt (4, userID);
					preparedStmt.execute();
					
					String query1 = " insert into examination (USER_ID, E_ID, E_Sub, E_Time)" + " values (?, ?, ?, ?)";
						
					PreparedStatement preparedStmt1 = con.prepareStatement(query1);
					preparedStmt1.setInt (1, userID);
					preparedStmt1.setString (2, C_ID);
					preparedStmt1.setString (3, C_Sub);
					preparedStmt1.setString (4, C_Exam);
					preparedStmt1.execute();
					System.out.print("Enrollment is success!\n");
					menuUser(userID);
				}else{
					System.out.println("\nYou used to register this course.\n");
					insertCourse(userID);
				}

			}else if (input==4){

				PreparedStatement checkCourseStatement = con.prepareStatement("SELECT * from course WHERE C_ID='1302004' AND USER_ID= '" + userID + "'");
				ResultSet resultCheckCourseStatement = checkCourseStatement.executeQuery();
				int count = 0;
				while(resultCheckCourseStatement.next()){
					count++;
				}

				if(count==0){
					statementCourse = con.prepareStatement("SELECT * from courselist WHERE C_ID= '" + 1302004 + "'");
					ResultSet resultCourse = statementCourse.executeQuery();
					
					String C_ID = null, C_Sub = null, C_Time = null, C_Exam = null; 
					while (resultCourse.next()){	
						C_ID = resultCourse.getString(1);
						C_Sub = resultCourse.getString(2);
						C_Time = resultCourse.getString(3);
						C_Exam = resultCourse.getString(4);
					}
					
					String query = " insert into course (C_ID, C_Time, C_Sub, USER_ID)"+ " values (?, ?, ?, ?)";
						
					PreparedStatement preparedStmt = con.prepareStatement(query);
					preparedStmt.setString (1, C_ID);
					preparedStmt.setString (2, C_Time);
					preparedStmt.setString (3, C_Sub);
					preparedStmt.setInt (4, userID);
					preparedStmt.execute();
					
					String query1 = " insert into examination (USER_ID, E_ID, E_Sub, E_Time)"
					        + " values (?, ?, ?, ?)";
						
					PreparedStatement preparedStmt1 = con.prepareStatement(query1);
					preparedStmt1.setInt (1, userID);
					preparedStmt1.setString (2, C_ID);
					preparedStmt1.setString (3, C_Sub);
					preparedStmt1.setString (4, C_Exam);
					preparedStmt1.execute();
					System.out.print("Enrollment is success!\n");
					menuUser(userID);
				}else{
					System.out.println("\nYou used to register this course.\n");
					insertCourse(userID);
				}
			}else if(input==0){
				menuUser(userID);
			}else{
				System.out.println("\nPlease enter number 1-4!");
				insertCourse(userID);
			}
			
		}catch(Exception e){
			System.out.println("\nPlease enter number only!");
			insertCourse(userID);
		}		
	}
	
	public static void insertMember() throws ClassNotFoundException, SQLException{
		System.out.println("\nPlease fill your information");
		Scanner input = new Scanner(System.in);
		System.out.print("Enter Name: ");
		String name = input.nextLine();
		System.out.print("Enter Surname: ");
		String surName = input.nextLine();
		System.out.print("Enter Nickname: ");
		String nickName = input.nextLine();
		System.out.print("Enter Gender (Male/Female): ");
		String gender = input.nextLine();
		System.out.print("Enter Address: ");
		String address = input.nextLine();
		System.out.print("Enter Phone number: ");
		String phoneNumber = input.nextLine();
		System.out.print("Enter School: ");
		String school = input.nextLine();
		System.out.print("Enter Expected University: ");
		String expected = input.nextLine();
		System.out.print("Enter your father name: ");
		String fatherName = input.nextLine();
		System.out.print("Enter birth date (DD/MM/YYYY): ");
		String birthDate = input.nextLine();
	
		try {
            Class.forName("com.mysql.jdbc.Driver");
            String url ="jdbc:mysql://localhost:3306/Database";
            Connection con = DriverManager.getConnection(url,"root","");
            String insertMySQL = "INSERT INTO user (USER_FNAME, USER_LNAME, School, ExpectedUni, USER_Phone, USER_Address, USER_Family, USER_Nickname, USER_Sex) "
            		+ "VALUES ('" + name +"', '" + surName +"', '" + school +"', '" + expected +"', '" + phoneNumber +"', '" + address +"', '" + fatherName +"', '" + nickName +"', '" + gender +"')";
			try {
		            Statement statement = (Statement) con.createStatement();
		            statement.execute(insertMySQL);
		            System.out.println("Registr Success!");
			 
			} catch (SQLException ex) {
		            System.out.println(ex.getMessage());
			}	
		} catch (Exception ex) {
			System.out.println(ex);
		}	            
	}
}