jsp签到功能实现

CREATE TABLE user_checkin (
    id INT AUTO_INCREMENT PRIMARY KEY,
    user_id INT NOT NULL,
    checkin_date DATE NOT NULL,
    UNIQUE (user_id, checkin_date)
);

<%@ page import="java.sql.*" %>
<%@ page import="java.util.Date" %>
<%@ page import="java.text.SimpleDateFormat" %>

<%
    int userId = (int) session.getAttribute("userId"); // 假设用户ID存储在session中
    if (userId == null) {
        response.sendRedirect("login.jsp"); // 未登录重定向到登录页面
        return;
    }

    Connection conn = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    try {
        Class.forName("com.mysql.jdbc.Driver");
        conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/yourdb", "username", "password");

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        String today = sdf.format(new Date());

        // 检查今天是否已经签到
        String checkQuery = "SELECT * FROM user_checkin WHERE user_id = ? AND checkin_date = ?";
        pstmt = conn.prepareStatement(checkQuery);
        pstmt.setInt(1, userId);
        pstmt.setString(2, today);
        rs = pstmt.executeQuery();

        if (!rs.next()) { // 如果今天未签到
            String insertQuery = "INSERT INTO user_checkin (user_id, checkin_date) VALUES (?, ?)";
            pstmt = conn.prepareStatement(insertQuery);
            pstmt.setInt(1, userId);
            pstmt.setString(2, today);
            pstmt.executeUpdate();

            out.println("签到成功！");
        } else {
            out.println("今天已经签到过了！");
        }
    } catch (Exception e) {
        out.println("签到失败：" + e.getMessage());
    } finally {
        if (rs != null) rs.close();
        if (pstmt != null) pstmt.close();
        if (conn != null) conn.close();
    }
%>