代码实现校园点餐系统

建立一个校园点餐系统需要考虑许多方面，包括用户管理、菜单管理、订单管理等。下面是一个基本的设计思路和代码实现，分为前端和后端。

后端设计思路：

1. 用户管理模块：处理用户注册、登录、信息修改等功能。
2. 菜单管理模块：包括菜品的添加、删除、修改和查询等功能。
3. 订单管理模块：处理用户下单、订单查询、订单状态更新等功能。
4. 数据库设计：使用MySQL存储用户信息、菜单信息、订单信息等。
5. 缓存管理：使用Redis缓存热门菜品、用户信息等，提高系统性能。

后端代码实现：

用户管理模块

# user_management.py

import mysql.connector

class UserManagement:
    def __init__(self):
        self.conn = mysql.connector.connect(
            host="localhost",
            user="username",
            password="password",
            database="campus_food_ordering"
        )
        self.cursor = self.conn.cursor()

    def register_user(self, username, password, email):
        # Check if user already exists
        self.cursor.execute("SELECT * FROM users WHERE username = %s", (username,))
        if self.cursor.fetchone():
            return False, "Username already exists"

        # Insert new user
        self.cursor.execute("INSERT INTO users (username, password, email) VALUES (%s, %s, %s)",
                            (username, password, email))
        self.conn.commit()
        return True, "User registered successfully"

    def login_user(self, username, password):
        self.cursor.execute("SELECT * FROM users WHERE username = %s AND password = %s",
                            (username, password))
        user = self.cursor.fetchone()
        if user:
            return True, "Login successful"
        else:
            return False, "Invalid username or password"

    def update_user_info(self, username, new_password=None, new_email=None):
        if new_password:
            self.cursor.execute("UPDATE users SET password = %s WHERE username = %s",
                                (new_password, username))
        if new_email:
            self.cursor.execute("UPDATE users SET email = %s WHERE username = %s",
                                (new_email, username))
        self.conn.commit()
        return True, "User information updated successfully"

菜单管理模块

# menu_management.py

import mysql.connector

class MenuManagement:
    def __init__(self):
        self.conn = mysql.connector.connect(
            host="localhost",
            user="username",
            password="password",
            database="campus_food_ordering"
        )
        self.cursor = self.conn.cursor()

    def add_dish(self, name, price, description):
        self.cursor.execute("INSERT INTO menu (name, price, description) VALUES (%s, %s, %s)",
                            (name, price, description))
        self.conn.commit()
        return True, "Dish added successfully"

    def delete_dish(self, dish_id):
        self.cursor.execute("DELETE FROM menu WHERE id = %s", (dish_id,))
        self.conn.commit()
        return True, "Dish deleted successfully"

    def update_dish(self, dish_id, new_price=None, new_description=None):
        if new_price:
            self.cursor.execute("UPDATE menu SET price = %s WHERE id = %s",
                                (new_price, dish_id))
        if new_description:
            self.cursor.execute("UPDATE menu SET description = %s WHERE id = %s",
                                (new_description, dish_id))
        self.conn.commit()
        return True, "Dish information updated successfully"

    def search_dish(self, keyword):
        self.cursor.execute("SELECT * FROM menu WHERE name LIKE %s", ('%' + keyword + '%',))
        dishes = self.cursor.fetchall()
        return dishes

订单管理模块

# order_management.py

import mysql.connector

class OrderManagement:
    def __init__(self):
        self.conn = mysql.connector.connect(
            host="localhost",
            user="username",
            password="password",
            database="campus_food_ordering"
        )
        self.cursor = self.conn.cursor()

    def place_order(self, user_id, dish_id, quantity):
        self.cursor.execute("INSERT INTO orders (user_id, dish_id, quantity) VALUES (%s, %s, %s)",
                            (user_id, dish_id, quantity))
        self.conn.commit()
        return True, "Order placed successfully"

    def get_user_orders(self, user_id):
        self.cursor.execute("SELECT * FROM orders WHERE user_id = %s", (user_id,))
        orders = self.cursor.fetchall()
        return orders

    def update_order_status(self, order_id, new_status):
        self.cursor.execute("UPDATE orders SET status = %s WHERE id = %s",
                            (new_status, order_id))
        self.conn.commit()
        return True, "Order status updated successfully"

前端设计思路：

1. 用户界面：提供注册、登录、个人信息修改等功能。
2. 菜单界面：展示菜单，支持搜索、添加购物车等操作。
3. 购物车界面：展示用户已选择的菜品和数量，支持修改数量、删除等操作。
4. 订单界面：展示用户的历史订单和当前订单状态。

前端代码实现：

这部分可以使用HTML、CSS和JavaScript实现，将提供完整的HTML、CSS和JavaScript代码来实现校园点餐系统的前端交互和页面布局。

HTML代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Campus Food Ordering System</title>
    <link rel="stylesheet" href="styles.css">
</head>
<body>
    <div id="menu">
        <h2>Menu</h2>
        <input type="text" id="searchInput" placeholder="Search...">
        <div id="menuItems">
            <!-- Menu items will be displayed here -->
        </div>
    </div>
    <div id="cart">
        <h2>Shopping Cart</h2>
        <ul id="cartItems">
            <!-- Cart items will be displayed here -->
        </ul>
        <button id="checkoutBtn">Checkout</button>
    </div>
    <div id="orders">
        <h2>Order History</h2>
        <ul id="orderHistory">
            <!-- User orders will be displayed here -->
        </ul>
    </div>
    <script src="script.js"></script>
</body>
</html>

CSS代码

/* styles.css */

body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}

#menu, #cart, #orders {
    float: left;
    width: 30%;
    padding: 20px;
    box-sizing: border-box;
}

#menu {
    border-right: 1px solid #ccc;
}

#menu h2, #cart h2, #orders h2 {
    margin-top: 0;
}

#searchInput {
    width: 100%;
    padding: 8px;
    margin-bottom: 10px;
}

#menuItems, #cartItems, #orderHistory {
    list-style-type: none;
    padding: 0;
}

#menuItems li, #cartItems li, #orderHistory li {
    margin-bottom: 10px;
    border: 1px solid #ccc;
    padding: 10px;
}

#checkoutBtn {
    display: block;
    margin-top: 10px;
    padding: 10px 20px;
    background-color: #007bff;
    color: #fff;
    border: none;
    cursor: pointer;
}

#checkoutBtn:hover {
    background-color: #0056b3;
}

JavaScript代码

// script.js

document.addEventListener("DOMContentLoaded", function() {
    const menuItems = document.getElementById("menuItems");
    const cartItems = document.getElementById("cartItems");
    const orderHistory = document.getElementById("orderHistory");
    const searchInput = document.getElementById("searchInput");
    const checkoutBtn = document.getElementById("checkoutBtn");

    // Dummy data for demonstration
    const menu = [
        { id: 1, name: "Hamburger", price: 5.99 },
        { id: 2, name: "Pizza", price: 8.99 },
        { id: 3, name: "Salad", price: 4.99 }
    ];

    const cart = [];
    const orders = [
        { id: 1, dish: "Hamburger", quantity: 2, status: "Delivered" },
        { id: 2, dish: "Pizza", quantity: 1, status: "In progress" }
    ];

    // Populate menu items
    function populateMenu() {
        menuItems.innerHTML = "";
        menu.forEach(item => {
            const li = document.createElement("li");
            li.textContent = `${item.name} - $${item.price}`;
            li.setAttribute("data-id", item.id);
            menuItems.appendChild(li);
        });
    }

    // Populate cart items
    function populateCart() {
        cartItems.innerHTML = "";
        cart.forEach(item => {
            const li = document.createElement("li");
            li.textContent = `${item.name} x${item.quantity} - $${item.price * item.quantity}`;
            cartItems.appendChild(li);
        });
    }

    // Populate order history
    function populateOrderHistory() {
        orderHistory.innerHTML = "";
        orders.forEach(order => {
            const li = document.createElement("li");
            li.textContent = `${order.dish} x${order.quantity} - ${order.status}`;
            orderHistory.appendChild(li);
        });
    }

    // Add item to cart
    function addToCart(itemId) {
        const selectedItem = menu.find(item => item.id === parseInt(itemId));
        const existingItem = cart.find(item => item.id === selectedItem.id);
        if (existingItem) {
            existingItem.quantity++;
        } else {
            cart.push({ ...selectedItem, quantity: 1 });
        }
        populateCart();
    }

    // Search menu items
    searchInput.addEventListener("input", function() {
        const keyword = this.value.trim().toLowerCase();
        const filteredMenu = menu.filter(item => item.name.toLowerCase().includes(keyword));
        populateMenu(filteredMenu);
    });

    // Checkout
    checkoutBtn.addEventListener("click", function() {
        // Perform checkout process
        alert("Checkout completed!");
    });

    // Initial population
    populateMenu();
    populateCart();
    populateOrderHistory();

    // Event delegation for adding items to cart
    menuItems.addEventListener("click", function(event) {
        if (event.target.tagName === "LI") {
            const itemId = event.target.getAttribute("data-id");
            addToCart(itemId);
        }
    });
});

这些代码实现了校园点餐系统的基本前端交互和页面布局，包括展示菜单、搜索菜品、添加购物车、展示购物车内容、结账等功能。在实际项目中，还需要添加更多的功能和样式来完善用户体验。