feat: implement Employee and EmployeeDAO classes with CRUD operations

employee-manager/src/main/java/com/example/employeemanager/Employee.java

@@ -0,0 +1,57 @@
+package com.example.employeemanager;
+
+public class Employee {
+    private int id;
+    private String name;
+    private String department;
+    private double salary;
+
+    public Employee(int id, String name, String department, double salary) {
+        this.id = id;
+        this.name = name;
+        this.department = department;
+        this.salary = salary;
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getDepartment() {
+        return department;
+    }
+
+    public void setDepartment(String department) {
+        this.department = department;
+    }
+
+    public double getSalary() {
+        return salary;
+    }
+
+    public void setSalary(double salary) {
+        this.salary = salary;
+    }
+
+    @Override
+    public String toString() {
+        return "Employee{" +
+                "id=" + id +
+                ", name='" + name + '\'' +
+                ", department='" + department + '\'' +
+                ", salary=" + salary +
+                '}';
+    }
+}

employee-manager/src/main/java/com/example/employeemanager/EmployeeDAO.java

@@ -0,0 +1,70 @@
+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();
+        }
+    }
+}

employee-manager/src/main/java/com/example/employeemanager/Main.java

@@ -0,0 +1,27 @@
+package com.example.employeemanager;
+
+import java.util.List;
+
+public class Main {
+    public static void main(String[] args) {
+        EmployeeDAO employeeDAO = new EmployeeDAO();
+
+        // Add a new employee
+        Employee emp1 = new Employee(1, "John Doe", "Engineering", 75000);
+        employeeDAO.addEmployee(emp1);
+
+        // Retrieve all employees
+        List<Employee> employees = employeeDAO.getAllEmployees();
+        System.out.println("All Employees:");
+        for (Employee emp : employees) {
+            System.out.println(emp);
+        }
+
+        // Update an employee
+        emp1.setSalary(80000);
+        employeeDAO.updateEmployee(emp1);
+
+        // Delete an employee
+        employeeDAO.deleteEmployee(1);
+    }
+}