Phone_Book_SQL

package com.company;

import java.io.IOException;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Scanner;


public class Main {
    private static final Scanner SCANNER = new Scanner(System.in);
    public static final String OP1 = "Get all names and phone numbers by char.";
    public static final String OP2 = "Get contact info by specific name.";
    public static final String OP3 = "Add contact.";
    public static final String OP4 = "Remove contact.";
    public static final String EXIT = "Exit";

    //to create a connection to our Data Base
    private static Connection myDataBase;
    //will convert our SQL request to a statement that the DB will recognize
    private static PreparedStatement statement;
    //address of our mysql
    final static String URL = "jdbc:mysql://localhost/";
    //init time zone UTC
    final static String HOLD_JDBC = "?useUnicode=true&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC";
    //name of the data base
    final static String DB_NAME = "phone_book";
    //name of user (in our case administrator)
    final static String DB_USER = "root";
    //administrator password
    final static String DB_PASS = "";

    public static void main(String[] args) throws IOException, SQLException {
        Contact_SQL contact_sql = new Contact_SQL(myDataBase, statement, URL, DB_NAME, HOLD_JDBC, DB_USER, DB_PASS);
        phoneBook_SQL(contact_sql);
    }

    static boolean phoneBook_SQL(Contact_SQL contact_sql) throws IOException, SQLException {
        String[] options = {OP1, OP2, OP3, OP4, EXIT};
        switch (Utils.menu(options)) {
            case 1:
                if (!(initSearchCharRequest(contact_sql)))
                    return phoneBook_SQL(contact_sql);
                break;
            case 2:
                if (!(initSearchNameRequest(contact_sql)))
                    return phoneBook_SQL(contact_sql);
                break;
            case 3:
                if (!(insertContactToTable(Utils.getNewContactInformation())))
                    return phoneBook_SQL(contact_sql);
                break;
            case 4:
                initRemoveContactByName(contact_sql);
                return phoneBook_SQL(contact_sql);
        }
        return false;
    }

    private static boolean initRemoveContactByName(Contact_SQL contact_sql) throws IOException, SQLException {
        System.out.println("Type contact name to remove : ");
        String name = SCANNER.nextLine();
        contact_sql.removeContactByName(name);
        return true;
    }

    private static boolean insertContactToTable(String[] info) throws SQLException {
        Contact_SQL contactSql = new Contact_SQL(myDataBase, statement, URL, DB_NAME, HOLD_JDBC, DB_USER, DB_PASS, info[0], info[1], Integer.parseInt(info[2]), info[3], info[4]);
        contactSql.saferInsert(contactSql);
        return false;
    }

    private static boolean initSearchNameRequest(Contact_SQL contact_sql) throws IOException, SQLException {
        System.out.print("Type Contact name : ");
        String userName = SCANNER.nextLine();
        if (userName.equals("back")) {
            return false;
        }
        if (contact_sql.getByName(userName)) {
            return true;
        }
        return initSearchNameRequest(contact_sql);
    }

    static boolean initSearchCharRequest(Contact_SQL contact_sql) throws SQLException, IOException {
        System.out.print("Type your char : ");
        String uChar = SCANNER.nextLine();
        if (Utils.isChar(uChar)) {
            contact_sql.getDataByChar(uChar);
            return initSearchCharRequest(contact_sql);
        } else if (uChar.equals("back")) {
            return false;
        } else
            throw new IOException("Please NOTE : you chose to search by CHAR found : STRING");
    }

}

=======================================================================================================================

package com.company;

import java.io.IOException;
import java.sql.*;
import java.util.Vector;

public abstract class SQL_Handler {
    //to create a connection to our Data Base
    private Connection myDataBase;
    //will convert our SQL request to a statement that the DB will recognize
    private PreparedStatement statement;
    //my localHost url
    private String URL;
    //init time zone UTC
    private String HOLD_JDBC;
    //name of the data base
    private String DB_NAME;
    //name of user (in our case administrator)
    private String DB_USER;
    //administrator password
    private String DB_PASS;
    private static final String SQL_CREATE_TABLE_COMMAND = "CREATE TABLE IF NOT EXISTS contacts_information " +
            "(char_Id TEXT (16) NOT NULL, " +
            "contact_name TEXT (16) NOT NULL, " +
            "phone_number INT PRIMARY KEY AUTO_INCREMENT, " +
            "city TEXT (16) NOT NULL, " +
            "address TEXT (16) NOT NULL)";
    public static final String SQL_INSERT_STATEMENT = "INSERT INTO contacts_information (char_Id,contact_name,phone_number,city,address) VALUES (?,?,?,?,?)";

    public SQL_Handler(Connection myDataBase, PreparedStatement statement, String URL, String DB_NAME, String HOLD_JDBC, String DB_USER, String DB_PASS) throws SQLException {
        this.myDataBase = myDataBase;
        this.statement = statement;
        this.URL = URL;
        this.DB_NAME = DB_NAME;
        this.HOLD_JDBC = HOLD_JDBC;
        this.DB_USER = DB_USER;
        this.DB_PASS = DB_PASS;
        this.myDataBase = DriverManager.getConnection(URL + DB_NAME + HOLD_JDBC, DB_USER, DB_PASS);
        initContactsTable();
    }

    void initContactsTable() throws SQLException {
        statement = myDataBase.prepareStatement(SQL_CREATE_TABLE_COMMAND);
        statement.execute();
    }

    boolean getDataByChar(String charId) throws SQLException {
        String sql = "SELECT * FROM contacts_information WHERE char_ID='" + charId + "'";
        ResultSet result = myDataBase.prepareStatement(sql).executeQuery();
        Vector<Contact_SQL> contact_sqls = new Vector<>();
        if (!result.next()) {
            System.out.println("No results for that char");
            return false;
        } else {
            for (result.first(); !result.isAfterLast(); result.next()) {
                Contact_SQL contactSql = new Contact_SQL(this.myDataBase, this.statement, this.URL, this.DB_NAME, this.HOLD_JDBC, this.DB_USER, this.DB_PASS, result.getString("char_Id"),
                        result.getString("contact_name"), result.getInt("phone_number"), result.getString("city"), result.getNString("address"));
                contact_sqls.add(contactSql);
            }
            for (Contact_SQL contact_sql : contact_sqls) {
                System.out.println(contact_sql);
            }
        }
        return true;
    }

    void saferInsert(Contact_SQL contact_sql) throws SQLException {
        statement = myDataBase.prepareStatement(SQL_INSERT_STATEMENT);
        statement.setString(1, contact_sql.getCharId());
        statement.setString(2, contact_sql.getName());
        statement.setInt(3, contact_sql.getPhone_number());
        statement.setString(4, contact_sql.getCity());
        statement.setString(5, contact_sql.getAddress());
        statement.execute();
        System.out.println("contact was add ! ");
    }

    boolean getByName(String name) throws IOException, SQLException {
        String sql = "SELECT * FROM contacts_information WHERE contact_name='" + name + "'";
        ResultSet result = myDataBase.prepareStatement(sql).executeQuery();
        Vector<Contact_SQL> contact_sqls = new Vector<>();
        if (!result.next()) {
            System.out.println("No results for that name");
            return false;
        } else {
            for (result.first(); !result.isAfterLast(); result.next()) {
                Contact_SQL contactSql = new Contact_SQL(this.myDataBase, this.statement, this.URL, this.DB_NAME, this.HOLD_JDBC, this.DB_USER, this.DB_PASS, result.getString("char_Id"),
                        result.getString("contact_name"), result.getInt("phone_number"), result.getString("city"), result.getNString("address"));
                contact_sqls.add(contactSql);
            }
            for (Contact_SQL contact_sql : contact_sqls) {
                System.out.println(contact_sql);
            }
            return true;
        }
    }

    void removeContactByName(String name) throws SQLException, IOException {
        if (getByName(name)){
            String sql = "DELETE FROM contacts_information WHERE contact_name='" +name + "'";
            statement = myDataBase.prepareStatement(sql);
            statement.execute();
            System.out.println("^^ Contact was deleted ^^");
        }
    }
}

===========================================================================================================================

package com.company;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;

public class Contact_SQL extends SQL_Handler {
    private String charId;
    private String name;
    private int phone_number;
    private String city;
    private String address;

    public Contact_SQL(Connection myDataBase, PreparedStatement statement, String URL, String DB_NAME, String HOLD_JDBC, String DB_USER, String DB_PASS) throws SQLException {
        super(myDataBase,statement,URL,DB_NAME,HOLD_JDBC,DB_USER,DB_PASS);
    }
    public Contact_SQL(Connection myDataBase, PreparedStatement statement, String URL, String DB_NAME, String HOLD_JDBC, String DB_USER, String DB_PASS, String charId, String name, int phone_number, String city, String address) throws SQLException {
        super(myDataBase, statement, URL, DB_NAME, HOLD_JDBC, DB_USER, DB_PASS);
        this.charId = charId;
        this.name = name;
        this.phone_number = phone_number;
        this.city = city;
        this.address = address;
    }

    @Override
    public String toString() {
        return "Contact_SQL{" + "charId='" + charId + '\'' + ", name='" + name + '\'' + ", phone_number=" + phone_number + ", city='" + city + '\'' + ", address='" + address + '\'' + '}';
    }

    public String getCharId() {
        return charId;
    }

    public String getName() {
        return name;
    }

    public int getPhone_number() {
        return phone_number;
    }

    public String getCity() {
        return city;
    }

    public String getAddress() {
        return address;
    }

}

===========================================================================================================================

package com.company;

import java.io.IOException;
import java.util.Scanner;

public class Utils {
    static final Scanner SCANNER = new Scanner(System.in);
    static final int CHAR_ZERO_VALUE = 48;
    static final int CHAR_NINE_VALUE = 57;

    public static int menu(String[] options) throws IOException {
        System.out.println("* MENU *");
        for (int i = 0; i < options.length; i++) {
            System.out.println((i + 1) + ". " + options[i]);
        }
        System.out.print("Type your choice : ");
        String choice = SCANNER.nextLine();
        if (!isNumber(choice.charAt(0)))
            throw new IOException("Must type only digits between " + 1 + " AND " + options.length);
        if (Integer.parseInt(choice) < 1 || Integer.parseInt(choice) > options.length) {
            throw new IOException("You choose Index OUT OF BOUND");
        } else
            return Integer.parseInt(choice);
    }

    static boolean isNumber(char userChar) {
        return userChar >= CHAR_ZERO_VALUE && userChar <= CHAR_NINE_VALUE;
    }
    static boolean isChar(String s){
        return s.length()==1;
    }
    static String[] getNewContactInformation() {
        String[] result = new String[5];
        System.out.print("Type name : ");
        result[1] = SCANNER.nextLine();
        result[0] = String.valueOf(result[1].charAt(0));
        System.out.print("Type phone number : ");
        result[2] = SCANNER.nextLine();
        System.out.print("Type city : ");
        result[3] = SCANNER.nextLine();
        System.out.print("Type address : ");
        result[4] = SCANNER.nextLine();
        return result;
    }
}