用户能进行任务管理。安排的任务可以分为未完成任务、已完成任务，未完成任务完成后将归档到已完成任务项，用户可以根据任务的性质来对任务进行分类，在调度任务时，可以按状态分组（所有任务、已完成任务，未完成任务）、按时间分组、按日期分组来查询。Javaweb代码

以下是一个简单的Javaweb代码实现任务管理系统：

Task.java

public class Task {
    private int id;
    private String name;
    private String description;
    private Date createTime;
    private Date finishTime;
    private boolean isCompleted;

    // constructors and getters/setters
}

TaskDao.java

public class TaskDao {
    private static final String JDBC_DRIVER = "com.mysql.cj.jdbc.Driver";
    private static final String DB_URL = "jdbc:mysql://localhost:3306/tasks?useSSL=false&serverTimezone=UTC";
    private static final String USER = "root";
    private static final String PASS = "password";

    private Connection conn;

    public TaskDao() {
        try {
            Class.forName(JDBC_DRIVER);
            conn = DriverManager.getConnection(DB_URL, USER, PASS);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public List<Task> getAllTasks() {
        List<Task> tasks = new ArrayList<>();
        String sql = "SELECT * FROM task";
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            ResultSet rs = ps.executeQuery();
            while (rs.next()) {
                Task task = new Task();
                task.setId(rs.getInt("id"));
                task.setName(rs.getString("name"));
                task.setDescription(rs.getString("description"));
                task.setCreateTime(rs.getDate("create_time"));
                task.setFinishTime(rs.getDate("finish_time"));
                task.setCompleted(rs.getBoolean("is_completed"));
                tasks.add(task);
            }
            rs.close();
            ps.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return tasks;
    }

    public List<Task> getTasksByStatus(boolean isCompleted) {
        List<Task> tasks = new ArrayList<>();
        String sql = "SELECT * FROM task WHERE is_completed = ?";
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            ps.setBoolean(1, isCompleted);
            ResultSet rs = ps.executeQuery();
            while (rs.next()) {
                Task task = new Task();
                task.setId(rs.getInt("id"));
                task.setName(rs.getString("name"));
                task.setDescription(rs.getString("description"));
                task.setCreateTime(rs.getDate("create_time"));
                task.setFinishTime(rs.getDate("finish_time"));
                task.setCompleted(rs.getBoolean("is_completed"));
                tasks.add(task);
            }
            rs.close();
            ps.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return tasks;
    }

    public List<Task> getTasksByDate(Date date) {
        List<Task> tasks = new ArrayList<>();
        String sql = "SELECT * FROM task WHERE create_time >= ? AND create_time < ?";
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            ps.setDate(1, new java.sql.Date(date.getTime()));
            Calendar calendar = Calendar.getInstance();
            calendar.setTime(date);
            calendar.add(Calendar.DATE, 1);
            ps.setDate(2, new java.sql.Date(calendar.getTimeInMillis()));
            ResultSet rs = ps.executeQuery();
            while (rs.next()) {
                Task task = new Task();
                task.setId(rs.getInt("id"));
                task.setName(rs.getString("name"));
                task.setDescription(rs.getString("description"));
                task.setCreateTime(rs.getDate("create_time"));
                task.setFinishTime(rs.getDate("finish_time"));
                task.setCompleted(rs.getBoolean("is_completed"));
                tasks.add(task);
            }
            rs.close();
            ps.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return tasks;
    }

    public boolean addTask(Task task) {
        String sql = "INSERT INTO task (name, description, create_time) VALUES (?, ?, ?)";
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            ps.setString(1, task.getName());
            ps.setString(2, task.getDescription());
            ps.setDate(3, new java.sql.Date(task.getCreateTime().getTime()));
            int rows = ps.executeUpdate();
            ps.close();
            return rows > 0;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return false;
    }

    public boolean completeTask(int taskId) {
        String sql = "UPDATE task SET is_completed = ?, finish_time = ? WHERE id = ?";
        try {
            PreparedStatement ps = conn.prepareStatement(sql);
            ps.setBoolean(1, true);
            ps.setDate(2, new java.sql.Date(System.currentTimeMillis()));
            ps.setInt(3, taskId);
            int rows = ps.executeUpdate();
            ps.close();
            return rows > 0;
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return false;
    }
}

TaskServlet.java

@WebServlet("/tasks")
public class TaskServlet extends HttpServlet {
    private TaskDao taskDao;

    public void init() {
        taskDao = new TaskDao();
    }

    public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String action = request.getParameter("action");
        if (action == null) {
            List<Task> allTasks = taskDao.getAllTasks();
            request.setAttribute("tasks", allTasks);
        } else if (action.equals("completed")) {
            List<Task> completedTasks = taskDao.getTasksByStatus(true);
            request.setAttribute("tasks", completedTasks);
        } else if (action.equals("unfinished")) {
            List<Task> unfinishedTasks = taskDao.getTasksByStatus(false);
            request.setAttribute("tasks", unfinishedTasks);
        } else if (action.equals("today")) {
            List<Task> todayTasks = taskDao.getTasksByDate(new Date());
            request.setAttribute("tasks", todayTasks);
        } else if (action.equals("date")) {
            String dateString = request.getParameter("date");
            SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
            try {
                Date date = format.parse(dateString);
                List<Task> tasksByDate = taskDao.getTasksByDate(date);
                request.setAttribute("tasks", tasksByDate);
            } catch (ParseException e) {
                e.printStackTrace();
            }
        }
        request.getRequestDispatcher("index.jsp").forward(request, response);
    }

    public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String action = request.getParameter("action");
        if (action.equals("add")) {
            String name = request.getParameter("name");
            String description = request.getParameter("description");
            Task task = new Task();
            task.setName(name);
            task.setDescription(description);
            task.setCreateTime(new Date());
            taskDao.addTask(task);
        } else if (action.equals("complete")) {
            int taskId = Integer.parseInt(request.getParameter("id"));
            taskDao.completeTask(taskId);
        }
        response.sendRedirect("tasks");
    }
}

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Task Management</title>
</head>
<body>
    <h1>Task Management</h1>
    <form action="tasks" method="post">
        <input type="hidden" name="action" value="add" />
        <label>Name:</label>
        <input type="text" name="name" required /><br />
        <label>Description:</label>
        <textarea name="description" required></textarea>
        <button type="submit">Add Task</button>
    </form>
    <br />
    <h2>All Tasks</h2>
    <table>
        <tr>
            <th>ID</th>
            <th>Name</th>
            <th>Description</th>
            <th>Create Time</th>
            <th>Finish Time</th>
            <th>Status</th>
            <th>Action</th>
        </tr>
        <c:forEach items="${tasks}" var="task">
            <tr>
                <td>${task.id}</td>
                <td>${task.name}</td>
                <td>${task.description}</td>
                <td>${task.createTime}</td>
                <td>${task.finishTime}</td>
                <td>${task.isCompleted ? 'Completed' : 'Unfinished'}</td>
                <td>
                    <c:if test="${!task.isCompleted}">
                        <form action="tasks" method="post" style="display: inline">
                            <input type="hidden" name="action" value="complete" />
                            <input type="hidden" name="id" value="${task.id}" />
                            <button type="submit">Complete</button>
                        </form>
                    </c:if>
                </td>
            </tr>
        </c:forEach>
    </table>
    <br />
    <h2>Completed Tasks</h2>
    <form action="tasks" method="get" style="display: inline">
        <input type="hidden" name="action" value="completed" />
        <button type="submit">Show Completed Tasks</button>
    </form>
    <br />
    <h2>Unfinished Tasks</h2>
    <form action="tasks" method="get" style="display: inline">
        <input type="hidden" name="action" value="unfinished" />
        <button type="submit">Show Unfinished Tasks</button>
    </form>
    <br />
    <h2>Tasks for Today</h2>
    <form action="tasks" method="get" style="display: inline">
        <input type="hidden" name="action" value="today" />
        <button type="submit">Show Tasks for Today</button>
    </form>
    <br />
    <h2>Tasks for a Specific Date</h2>
    <form action="tasks" method="get">
        <input type="hidden" name="action" value="date" />
        <label>Date:</label>
        <input type="date" name="date" required />
        <button type="submit">Show Tasks</button>
    </form>
</body>
</html>

这个简单的任务管理系统包含了基本的CRUD操作，以及根据不同条件查询任务的功能。它使用MySQL作为数据库，使用JDBC连接数据库并执行SQL语句。用户可以在前端页面上添加任务、标记任务为已完成、查看所有任务、查看已完成任务、查看未完成任务、查看今天的任务、查看指定日期的任务。