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# DAO con PreparedStatement

```java
package DAO;

import Util.Lector;
import Modelo.Profesor;

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

public class ProfesorDAOPrepStat {

    public List<Profesor> findAll() {
        List<Profesor> lista = new ArrayList<>();
        String sql = "SELECT * FROM profesores";
        try (Connection con = DriverManager.getConnection(Lector.getInstancia().getServidor(), Lector.getInstancia().getUsuario(), Lector.getInstancia().getContraseña());
             PreparedStatement ps = con.prepareStatement(sql)) {

            ResultSet rs = ps.executeQuery();
            while (rs.next()) {
                Profesor profesor = new Profesor(
                        rs.getInt(1),
                        rs.getString(2),
                        rs.getString(3),
                        rs.getDate(4).toLocalDate(),
                        rs.getInt(5)
                );
                lista.add(profesor);
            }

        } catch (SQLException e) {
            System.out.println(e.getMessage());
        }
        return lista;
    }

    public Optional<Profesor> findById(int id) {
        String sql = "SELECT * FROM profesores WHERE id = ?";
        try (Connection con = DriverManager.getConnection(Lector.getInstancia().getServidor(), Lector.getInstancia().getUsuario(), Lector.getInstancia().getContraseña());
             PreparedStatement ps = con.prepareStatement(sql)) {

            ps.setInt(1, id);
            ResultSet rs = ps.executeQuery();

            if (rs.next()) {
                Profesor profesor = new Profesor(
                        rs.getInt("id"),
                        rs.getString("nombre"),
                        rs.getString("email"),
                        rs.getDate("fecha_contrato").toLocalDate(),
                        rs.getInt("id_departamento")
                );
                return Optional.of(profesor);
            }

        } catch (SQLException e) {
            System.out.println(e.getMessage());
        }
        return Optional.empty();
    }

    public int insert(Profesor p) {
        String sql = "INSERT INTO profesores (nombre, email, fecha_contrato, id_departamento) VALUES (?, ?, ?, ?)";
        try (Connection con = DriverManager.getConnection(Lector.getInstancia().getServidor(), Lector.getInstancia().getUsuario(), Lector.getInstancia().getContraseña());
             PreparedStatement ps = con.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS)) {

            ps.setString(1, p.getNombre());
            ps.setString(2, p.getEmail());
            ps.setObject(3, p.getFechaContrato()); // Uso de setObject para LocalDate
            ps.setInt(4, p.getIdDepartamento());

            int filasAfectadas = ps.executeUpdate();

            if (filasAfectadas > 0) {
                ResultSet rs = ps.getGeneratedKeys();
                if (rs.next()) {
                    int id = rs.getInt(1);
                    p.setId(id);
                    return id;
                }
            }
        } catch (SQLException e) {
            System.out.println(e.getMessage());
        }
        return -1;
    }

    public Optional<Profesor> update(Profesor p) {
        String sql = "UPDATE profesores SET nombre = ?, email = ?, fecha_contrato = ?, id_departamento = ? WHERE id = ?";
        try (Connection con = DriverManager.getConnection(Lector.getInstancia().getServidor(), Lector.getInstancia().getUsuario(), Lector.getInstancia().getContraseña());
             PreparedStatement ps = con.prepareStatement(sql)) {

            ps.setString(1, p.getNombre());
            ps.setString(2, p.getEmail());
            ps.setObject(3, p.getFechaContrato());
            ps.setInt(4, p.getIdDepartamento());
            ps.setInt(5, p.getId());

            int filasAfectadas = ps.executeUpdate();
            if (filasAfectadas > 0) {
                return Optional.of(p);
            }
        } catch (SQLException e) {
            System.out.println(e.getMessage());
        }
        return Optional.empty();
    }

    public boolean remove(int id) {
        String sql = "DELETE FROM profesores WHERE id = ?";
        try (Connection con = DriverManager.getConnection(Lector.getInstancia().getServidor(), Lector.getInstancia().getUsuario(), Lector.getInstancia().getContraseña());
             PreparedStatement ps = con.prepareStatement(sql)) {

            ps.setInt(1, id);
            int filasAfectadas = ps.executeUpdate();
            return filasAfectadas > 0;

        } catch (SQLException e) {
            System.out.println(e.getMessage());
        }
        return false;
    }
}

```


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