EmployeeDAO.java

package com.example.employeemanager;

import java.sql.*;
import java.util.ArrayList;
import java.util.List;

public class EmployeeDAO {
    private final String url = "jdbc:mysql://localhost:3306/employeedb";
    private final String user = "root";
    private final String password = "password";

    public Connection connect() throws SQLException {
        return DriverManager.getConnection(url, user, password);
    }

    public void addEmployee(Employee employee) {
        String sql = "INSERT INTO employees (id, name, department, salary) VALUES (?, ?, ?, ?)";
        try (Connection conn = connect(); PreparedStatement pstmt = conn.prepareStatement(sql)) {
            pstmt.setInt(1, employee.getId());
            pstmt.setString(2, employee.getName());
            pstmt.setString(3, employee.getDepartment());
            pstmt.setDouble(4, employee.getSalary());
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public List<Employee> getAllEmployees() {
        List<Employee> employees = new ArrayList<>();
        String sql = "SELECT * FROM employees";
        try (Connection conn = connect(); Statement stmt = conn.createStatement(); ResultSet rs = stmt.executeQuery(sql)) {
            while (rs.next()) {
                Employee employee = new Employee(
                        rs.getInt("id"),
                        rs.getString("name"),
                        rs.getString("department"),
                        rs.getDouble("salary")
                );
                employees.add(employee);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return employees;
    }

    public void updateEmployee(Employee employee) {
        String sql = "UPDATE employees SET name = ?, department = ?, salary = ? WHERE id = ?";
        try (Connection conn = connect(); PreparedStatement pstmt = conn.prepareStatement(sql)) {
            pstmt.setString(1, employee.getName());
            pstmt.setString(2, employee.getDepartment());
            pstmt.setDouble(3, employee.getSalary());
            pstmt.setInt(4, employee.getId());
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    public void deleteEmployee(int id) {
        String sql = "DELETE FROM employees WHERE id = ?";
        try (Connection conn = connect(); PreparedStatement pstmt = conn.prepareStatement(sql)) {
            pstmt.setInt(1, id);
            pstmt.executeUpdate();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}