create database feherbt;
 
use feherbt;
 
create table employee (
  id int not null primary key auto_increment,
  name varchar(30),
  city varchar(30),
  salary double
);
 
grant all privileges 
on feherbt.* 
to 'feherbt'@'localhost'
identified by 'titok';

public class Employee {
    int id;
    String name;
    String city;
    double salary;
}

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.SQLException;
 
public class Mariadb {    
 
    private static Connection tryConnectDb() throws SQLException {
        String url = "jdbc:mariadb://localhost:3306/feherbt";
        Connection conn = DriverManager.getConnection(url,
                "feherbt", "titok");
        return conn;
    }
 
    public static Connection connectDb() {        
        Connection conn = null;
        try  {
            conn = tryConnectDb();
        } catch (SQLException e) {
            System.err.println("Hiba! A kapcsolódás sikertelen!");
            System.err.println(e.getMessage());
        }
        return conn;
    }    
}

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
 
public class Database {
    public List<Employee> tryGetEmployees() throws SQLException {
        List<Employee> employees = new ArrayList<>();        
        Connection conn = Mariadb.connectDb();
        String sql = "select id, name, city, salary from employee";
        Statement stmt = conn.createStatement();        
        ResultSet rs = stmt.executeQuery(sql);
        while(rs.next()) {
            Employee employee = new Employee();
            employee.id = rs.getInt("id");
            employee.name = rs.getString("name");
            employee.city = rs.getString("city");
            employee.salary = rs.getDouble("salary");
            employees.add(employee);
        }
        conn.close();        
        return employees;
    }
 
    public List<Employee> getEmployees() {
        List<Employee> employees = null;
        try {
            employees = tryGetEmployees();
        } catch (SQLException e) {
            System.err.println("Hiba! A lekérdezés sikertelen!");
            System.err.println(e.getMessage());
        }
        return employees;
    }
 
    public void tryInsertEmployee(
            String name, String city, double salary) 
            throws SQLException {        
        Connection conn = Mariadb.connectDb();
        String sql = "insert into employee " +
                "(name, city, salary) values " +
                "(?, ?, ?)";
        PreparedStatement pstmt = conn.prepareStatement(sql);
        pstmt.setString(1, name);
        pstmt.setString(2, city);
        pstmt.setDouble(3, salary);
        pstmt.execute();
        conn.close();        
    }
 
    public void insertEmployee(
            String name, String city, double salary) {
        try {
            tryInsertEmployee(name, city, salary);
        } catch (SQLException ex) {
            System.err.println("Hiba! A beszúrás sikertelen!");
            System.err.println(ex.getMessage());
        }
    }
}

import java.sql.Connection;
import java.util.ArrayList;
import java.util.List;
 
public class Main {    
    public static void main(String[] args) {
        List<Employee> employees = new ArrayList<>();
        Database database = new Database();
 
        database.insertEmployee("Cseviczki Zsolt", "Szolnok", 3450000);
        employees = database.getEmployees();
        for(Employee employee: employees) {
            System.out.println(employee.name);
        }
    }
}