系统功能基本要求：职工信息，包括职工编号、职工姓名、性别、年龄、职称等；出勤记录信息， 包括上班打卡时间，下班打开时间，缺勤记录等；出差信息，包括出差起始时间、结束时间、统计总共 天数等；请假信息，包括请假开始时间，结束时间，统计请假天数等；加班信息，包括加班开始时间、 结束时间、统计加班总时间。 按照此要求给出JDBC代码

以下是一个简单的JDBC代码示例，用于连接并操作数据库中的职工信息表：

import java.sql.*;

public class EmployeeJDBC {
    private Connection conn = null;
    private PreparedStatement pstmt = null;
    private ResultSet rs = null;

    // 连接数据库
    public void connect() throws ClassNotFoundException, SQLException {
        Class.forName("com.mysql.jdbc.Driver");
        String url = "jdbc:mysql://localhost:3306/employees";
        String user = "root";
        String password = "password";
        conn = DriverManager.getConnection(url, user, password);
    }

    // 插入职工信息
    public void insertEmployee(Employee employee) throws SQLException {
        String sql = "INSERT INTO employee (employee_id, employee_name, gender, age, title) VALUES (?, ?, ?, ?, ?)";
        pstmt = conn.prepareStatement(sql);
        pstmt.setInt(1, employee.getEmployeeId());
        pstmt.setString(2, employee.getEmployeeName());
        pstmt.setString(3, employee.getGender());
        pstmt.setInt(4, employee.getAge());
        pstmt.setString(5, employee.getTitle());
        pstmt.executeUpdate();
    }

    // 查询职工信息
    public Employee getEmployee(int employeeId) throws SQLException {
        String sql = "SELECT * FROM employee WHERE employee_id = ?";
        pstmt = conn.prepareStatement(sql);
        pstmt.setInt(1, employeeId);
        rs = pstmt.executeQuery();
        if (rs.next()) {
            Employee employee = new Employee();
            employee.setEmployeeId(rs.getInt("employee_id"));
            employee.setEmployeeName(rs.getString("employee_name"));
            employee.setGender(rs.getString("gender"));
            employee.setAge(rs.getInt("age"));
            employee.setTitle(rs.getString("title"));
            return employee;
        } else {
            return null;
        }
    }

    // 更新职工信息
    public void updateEmployee(Employee employee) throws SQLException {
        String sql = "UPDATE employee SET employee_name = ?, gender = ?, age = ?, title = ? WHERE employee_id = ?";
        pstmt = conn.prepareStatement(sql);
        pstmt.setString(1, employee.getEmployeeName());
        pstmt.setString(2, employee.getGender());
        pstmt.setInt(3, employee.getAge());
        pstmt.setString(4, employee.getTitle());
        pstmt.setInt(5, employee.getEmployeeId());
        pstmt.executeUpdate();
    }

    // 删除职工信息
    public void deleteEmployee(int employeeId) throws SQLException {
        String sql = "DELETE FROM employee WHERE employee_id = ?";
        pstmt = conn.prepareStatement(sql);
        pstmt.setInt(1, employeeId);
        pstmt.executeUpdate();
    }

    // 关闭连接
    public void close() throws SQLException {
        if (rs != null) {
            rs.close();
        }
        if (pstmt != null) {
            pstmt.close();
        }
        if (conn != null) {
            conn.close();
        }
    }
}

其中，`Employee`类为职工信息类，包括职工编号、职工姓名、性别、年龄、职称等属性和对应的get/set方法。在该示例中，我们使用了预处理语句来执行SQL语句，避免了SQL注入攻击。同时，我们还提供了连接、插入、查询、更新和删除职工信息的方法，以及关闭连接的方法。