Ex1

package Ex1; /**
 * Created by josephawwal on 01/02/2018.
 */


// Implement a Hashmap-based index.

import java.sql.*;
import java.util.HashMap;
import java.util.logging.Level;
import java.util.logging.Logger;

//User class


class Users {

    private int ID;
    private String fName;
    private String lName;
    private int Age;

    public Users() {
    }

    public Users(int id, String fname, String lname, int age) {

        this.ID = id;
        this.fName = fname;
        this.lName = lname;
        this.Age = age;

    }

    public int getID() {
        return this.ID;

    }

    public String getfName() {
        return this.fName;
    }

    public String getlName() {
        return this.lName;
    }

    public int getAge() {
        return this.Age;
    }

    // toString method to display data

    public String toString() {

        return this.ID + " " + this.fName + " " + this.lName + " " + this.Age;
    }
}

public class Work {

    public static Connection getConnection() {

        Connection conn = null;

        try {

            conn = DriverManager.getConnection("jdbc:mysql://localhost/simple_db",
                    "root", "");
            if (conn != null) {
                System.out.println("Connection to database established...");
            }
        } catch (SQLException ex) {
            Logger.getLogger(Work.class.getName()).log(Level.SEVERE, null, ex);

        }
        return conn;
    }

    public static void main(String[] args) {

        //Creating HashMap

        HashMap<Integer, Users> map = new HashMap<Integer, Users>();

        Statement st = null;
        ResultSet rs = null;
        Connection conn = getConnection();
        Users u;

        try {
            st = conn.createStatement();
            rs = st.executeQuery("SELECT * FROM users");
            while (rs.next()) {

                Integer id = rs.getInt("id");
                String fname = rs.getString("fname");
                String lname = rs.getString("lname");
                int age = rs.getInt("age");

                u = new Users(id, fname, lname, age);

                // Put data in the hashmap
                map.put(id, u);
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }


        // Display data from hashmap
        for (Integer i : map.keySet()) {

            Users us = map.get(i);
            //System.out.println(us.getID() + " " + us.getfName() + " " + us.getlName() + " " + us.getAge());

        }


        //Show data from hashmap using toString method
        System.out.println(("Showing data with toString: "));
        for (Integer i : map.keySet()) {
            Users us = map.get(i);
            System.out.println(us.toString());
        }


    }


}