本文将从实践角度出发，通过具体的代码示例，深入讲解外卖平台核心功能的实现。光合同城作为专业的外卖系统开发商，将分享在实际项目中的技术实践和经验总结。
一：外卖系统开发环境搭建
1.1 技术栈选择
光合同城推荐以下技术栈用于外卖系统开发：
后端技术栈：
MySQL + Redis + Elasticsearch
RabbitMQ消息队列
Nginx网关
Docker容器化
前端技术栈：
用户端：Uni-app跨平台框架
商家/骑手端：Vue.js + Element UI
管理后台：React + Ant Design
移动端：
Android：Kotlin + Jetpack
iOS：Swift + SwiftUI
1.2 服务项目结构
food-delivery-platform/
├── food-delivery-gateway/ # API网关
├── food-delivery-auth/ # 认证授权中心
├── food-delivery-user/ # 用户服务
├── food-delivery-merchant/ # 商家服务
├── food-delivery-product/ # 商品服务
├── food-delivery-order/ # 订单服务
├── food-delivery-payment/ # 支付服务
├── food-delivery-delivery/ # 配送服务
├── food-delivery-message/ # 消息服务
└── food-delivery-monitor/ # 监控服务
二：订单系统的核心实现
2.1 订单状态机设计
订单状态流转是外卖系统的核心逻辑。光合同城设计的状态机确保订单状态变更的准确性和一致性。
订单状态枚举：
public enum OrderStatus {
// 待支付（用户提交订单后）
WAITING_PAYMENT(1, "待支付"),
// 已支付（用户支付成功后）
PAID(2, "已支付"),
// 商家已接单
MERCHANT_CONFIRMED(3, "商家已接单"),
// 商家拒单
MERCHANT_REJECTED(4, "商家拒单"),
// 制作中
PREPARING(5, "制作中"),
// 制作完成
PREPARED(6, "制作完成"),
// 骑手已接单
RIDER_ACCEPTED(7, "骑手已接单"),
// 骑手已取餐
PICKED_UP(8, "骑手已取餐"),
// 配送中
DELIVERING(9, "配送中"),
// 已送达
DELIVERED(10, "已送达"),
// 已完成（用户确认收货）
COMPLETED(11, "已完成"),
// 已取消
CANCELLED(12, "已取消"),
// 售后中
AFTER_SALE(13, "售后中"),
// 已退款
REFUNDED(14, "已退款");
private final int code;
private final String description;
OrderStatus(int code, String description) {
this.code = code;
this.description = description;
}
// 状态流转校验
public boolean canTransferTo(OrderStatus targetStatus) {
Map<OrderStatus, List<OrderStatus>> allowedTransfers = Map.of(
WAITING_PAYMENT, Arrays.asList(PAID, CANCELLED),
PAID, Arrays.asList(MERCHANT_CONFIRMED, MERCHANT_REJECTED, REFUNDED),
MERCHANT_CONFIRMED, Arrays.asList(PREPARING, CANCELLED),
PREPARING, Arrays.asList(PREPARED, CANCELLED),
PREPARED, Arrays.asList(RIDER_ACCEPTED, CANCELLED),
RIDER_ACCEPTED, Arrays.asList(PICKED_UP, CANCELLED),
PICKED_UP, Arrays.asList(DELIVERING, CANCELLED),
DELIVERING, Arrays.asList(DELIVERED),
DELIVERED, Arrays.asList(COMPLETED, AFTER_SALE),
AFTER_SALE, Arrays.asList(REFUNDED, COMPLETED)
);
return allowedTransfers.getOrDefault(this, Collections.emptyList())
.contains(targetStatus);
}
}
2.2 订单创建服务实现
订单创建涉及多个服务的协同工作，需要保证数据一致性。光合同城采用分布式事务解决方案。
订单创建核心代码示例：
@Service
@Slf4j
public class OrderServiceImpl implements OrderService {
@Autowired
private ProductService productService;
@Autowired
private InventoryService inventoryService;
@Autowired
private PaymentService paymentService;
@Autowired
private MessageService messageService;
@Autowired
private RocketMQTemplate rocketMQTemplate;
@Override
@Transactional(rollbackFor = Exception.class)
public OrderCreateResponse createOrder(OrderCreateRequest request) {
// 1. 参数校验
validateOrderRequest(request);
// 2. 验证商品和库存
List<ProductDTO> products = validateProductsAndInventory(request.getItems());
// 3. 计算订单金额
OrderAmountDTO amount = calculateOrderAmount(request, products);
// 4. 创建订单记录（初始状态为待支付）
OrderDTO order = saveOrder(request, products, amount);
try {
// 5. 预扣库存（防止超卖）
inventoryService.preDeductInventory(request.getItems());
// 6. 发送订单创建消息到MQ
OrderCreatedEvent event = new OrderCreatedEvent();
event.setOrderId(order.getOrderId());
event.setUserId(order.getUserId());
event.setAmount(order.getTotalAmount());
rocketMQTemplate.send("order-topic",
MessageBuilder.withPayload(event).build());
// 7. 创建支付预订单
PaymentPreOrderDTO paymentOrder = paymentService.createPreOrder(
order.getOrderId(),
order.getTotalAmount(),
"外卖订单支付"
);
// 8. 返回结果
return OrderCreateResponse.builder()
.orderId(order.getOrderId())
.orderNo(order.getOrderNo())
.status(order.getStatus())
.payAmount(order.getTotalAmount())
.paymentInfo(paymentOrder)
.expireTime(LocalDateTime.now().plusMinutes(15))
.build();
} catch (Exception e) {
log.error("创建订单失败", e);
// 发送订单创建失败消息，触发补偿操作
rocketMQTemplate.send("order-compensate-topic",
MessageBuilder.withPayload(order.getOrderId()).build());
throw new BusinessException("订单创建失败，请重试");
}
}
/**
* 计算订单金额
*/
private OrderAmountDTO calculateOrderAmount(OrderCreateRequest request,
List<ProductDTO> products) {
BigDecimal productAmount = BigDecimal.ZERO;
Map<Long, ProductDTO> productMap = products.stream()
.collect(Collectors.toMap(ProductDTO::getProductId, p -> p));
// 计算商品总价
for (OrderItemRequest item : request.getItems()) {
ProductDTO product = productMap.get(item.getProductId());
BigDecimal itemTotal = product.getPrice()
.multiply(new BigDecimal(item.getQuantity()));
productAmount = productAmount.add(itemTotal);
}
// 配送费计算
BigDecimal deliveryFee = calculateDeliveryFee(
request.getDeliveryAddress(),
request.getMerchantId()
);
// 包装费
BigDecimal packageFee = calculatePackageFee(request.getItems());
// 优惠券抵扣
BigDecimal couponDiscount = calculateCouponDiscount(
request.getCouponId(),
productAmount
);
// 会员折扣
BigDecimal memberDiscount = calculateMemberDiscount(
request.getUserId(),
productAmount
);
// 订单总金额
BigDecimal totalAmount = productAmount
.add(deliveryFee)
.add(packageFee)
.subtract(couponDiscount)
.subtract(memberDiscount);
// 确保金额不小于0
totalAmount = totalAmount.max(BigDecimal.ZERO);
return OrderAmountDTO.builder()
.productAmount(productAmount)
.deliveryFee(deliveryFee)
.packageFee(packageFee)
.couponDiscount(couponDiscount)
.memberDiscount(memberDiscount)
.totalAmount(totalAmount)
.build();
}
/**
* 保存订单到数据库
*/
private OrderDTO saveOrder(OrderCreateRequest request,
List<ProductDTO> products,
OrderAmountDTO amount) {
Order order = new Order();
order.setOrderNo(generateOrderNo());
order.setUserId(request.getUserId());
order.setMerchantId(request.getMerchantId());
order.setStatus(OrderStatus.WAITING_PAYMENT.getCode());
order.setProductAmount(amount.getProductAmount());
order.setDeliveryFee(amount.getDeliveryFee());
order.setPackageFee(amount.getPackageFee());
order.setDiscountAmount(amount.getCouponDiscount()
.add(amount.getMemberDiscount()));
order.setTotalAmount(amount.getTotalAmount());
order.setDeliveryAddress(request.getDeliveryAddress());
order.setExpectDeliveryTime(request.getExpectDeliveryTime());
order.setRemark(request.getRemark());
// 保存订单主表
orderMapper.insert(order);
// 保存订单商品明细
List<OrderItem> orderItems = new ArrayList<>();
Map<Long, ProductDTO> productMap = products.stream()
.collect(Collectors.toMap(ProductDTO::getProductId, p -> p));
for (OrderItemRequest itemRequest : request.getItems()) {
ProductDTO product = productMap.get(itemRequest.getProductId());
OrderItem orderItem = new OrderItem();
orderItem.setOrderId(order.getId());
orderItem.setProductId(itemRequest.getProductId());
orderItem.setProductName(product.getName());
orderItem.setProductImage(product.getMainImage());
orderItem.setQuantity(itemRequest.getQuantity());
orderItem.setPrice(product.getPrice());
orderItem.setTotalPrice(product.getPrice()
.multiply(new BigDecimal(itemRequest.getQuantity())));
orderItems.add(orderItem);
}
orderItemMapper.batchInsert(orderItems);
// 记录订单状态变更日志
OrderStatusLog statusLog = new OrderStatusLog();
statusLog.setOrderId(order.getId());
statusLog.setFromStatus(0);
statusLog.setToStatus(order.getStatus());
statusLog.setRemark("订单创建");
orderStatusLogMapper.insert(statusLog);
return convertToDTO(order, orderItems);
}
// 其他辅助方法省略...
}
三：智能配送系统实现
3.1 骑手调度算法
智能调度是提高配送效率的关键。光合同城开发的调度算法综合考虑多种因素。
骑手匹配算法代码示例：
class RiderDispatchSystem:
def __init__(self):
self.rider_pool = RiderPool()
self.order_queue = OrderQueue()
self.map_service = MapService()
def dispatch_order(self, order):
"""
智能分配骑手
"""
# 获取可用骑手列表
available_riders = self.rider_pool.get_available_riders(
order.merchant_location,
order.expected_delivery_time
)
if not available_riders:
return self.handle_no_rider_available(order)
# 为每个骑手计算匹配分数
rider_scores = []
for rider in available_riders:
score = self.calculate_rider_score(rider, order)
rider_scores.append((rider, score))
# 按分数排序，选择最优骑手
rider_scores.sort(key=lambda x: x[1], reverse=True)
best_rider = rider_scores[0][0]
# 分配订单给骑手
assignment_result = self.assign_order_to_rider(best_rider, order)
# 更新骑手状态
self.update_rider_status(best_rider, order)
# 发送推送通知
self.send_notification(best_rider, order)
return assignment_result
def calculate_rider_score(self, rider, order):
"""
计算骑手匹配分数
分数越高表示匹配度越好
"""
score = 100.0 # 基础分数
# 1. 距离因素（40%权重）
distance = self.map_service.calculate_distance(
rider.current_location,
order.merchant_location
)
distance_score = self.calculate_distance_score(distance)
score += distance_score * 0.4
# 2. 骑手评级（20%权重）
rating_score = rider.rating * 20 # rating是0-5的评分
score += rating_score * 0.2
# 3. 骑手负载（15%权重）
load_score = self.calculate_load_score(rider.current_load)
score += load_score * 0.15
# 4. 历史表现（15%权重）
performance_score = self.calculate_performance_score(rider)
score += performance_score * 0.15
# 5. 特殊技能（10%权重）
# 如：熟悉某区域、能处理特殊订单等
skill_score = self.calculate_skill_score(rider, order)
score += skill_score * 0.1
# 惩罚项
penalties = self.calculate_penalties(rider, order)
score -= penalties
return max(score, 0) # 确保分数不为负
def calculate_distance_score(self, distance_km):
"""
根据距离计算分数，距离越近分数越高
"""
if distance_km <= 1:
return 100
elif distance_km <= 3:
return 80
elif distance_km <= 5:
return 60
elif distance_km <= 8:
return 40
elif distance_km <= 10:
return 20
else:
return 0
def calculate_load_score(self, current_load):
"""
计算骑手负载分数
当前订单数越少，分数越高
"""
if current_load == 0:
return 100
elif current_load == 1:
return 80
elif current_load == 2:
return 60
elif current_load == 3:
return 40
elif current_load == 4:
return 20
else:
return 0 # 超过4单不再分配新订单
def calculate_performance_score(self, rider):
"""
计算骑手历史表现分数
基于准时率、投诉率等指标
"""
performance_score = 0
# 准时率（0-100分）
if rider.on_time_rate >= 0.98:
performance_score += 40
elif rider.on_time_rate >= 0.95:
performance_score += 30
elif rider.on_time_rate >= 0.90:
performance_score += 20
elif rider.on_time_rate >= 0.85:
performance_score += 10
# 投诉率（负向指标）
complaint_rate = rider.complaint_count / max(rider.total_orders, 1)
if complaint_rate <= 0.01:
performance_score += 30
elif complaint_rate <= 0.03:
performance_score += 20
elif complaint_rate <= 0.05:
performance_score += 10
# 平均评分
performance_score += rider.avg_rating * 10
return min(performance_score, 100)
def calculate_skill_score(self, rider, order):
"""
计算骑手技能匹配分数
"""
skill_score = 0
# 区域熟悉度
if order.delivery_area in rider.familiar_areas:
skill_score += 30
# 订单类型匹配
if order.order_type == "large" and "can_handle_large_order" in rider.skills:
skill_score += 20
# 特殊时段
if order.is_peak_hour and "peak_hour_experience" in rider.skills:
skill_score += 20
# 天气适应性
if order.bad_weather and "bad_weather_delivery" in rider.skills:
skill_score += 30
return min(skill_score, 100)
def calculate_penalties(self, rider, order):
"""
计算惩罚项
"""
penalties = 0
# 近期拒单惩罚
penalties += rider.recent_rejection_count * 10
# 超时取餐历史
if rider.avg_pickup_delay_minutes > 10:
penalties += 20
elif rider.avg_pickup_delay_minutes > 5:
penalties += 10
# 当前位置到商户的预估时间
eta_to_merchant = self.map_service.estimate_eta(
rider.current_location,
order.merchant_location
)
# 如果预计到达时间超过15分钟，增加惩罚
if eta_to_merchant > 15:
penalties += (eta_to_merchant - 15) * 2
return penalties
def batch_dispatch_optimization(self, orders, riders):
"""
批量订单分配优化
使用匈牙利算法解决指派问题
"""
n = len(orders)
m = len(riders)
# 构建成本矩阵
cost_matrix = np.zeros((n, m))
for i, order in enumerate(orders):
for j, rider in enumerate(riders):
score = self.calculate_rider_score(rider, order)
# 将分数转换为成本（分数越高，成本越低）
cost_matrix[i][j] = 1000 - score
# 使用匈牙利算法找到最小成本分配
row_ind, col_ind = linear_sum_assignment(cost_matrix)
# 构建分配结果
assignments = []
total_cost = 0
for i, j in zip(row_ind, col_ind):
if i < n and j < m:
assignment = {
'order_id': orders[i].order_id,
'rider_id': riders[j].rider_id,
'cost': cost_matrix[i][j],
'score': 1000 - cost_matrix[i][j]
}
assignments.append(assignment)
total_cost += cost_matrix[i][j]
# 过滤掉分数过低的分配
valid_assignments = [
a for a in assignments
if a['score'] >= self.min_dispatch_score
]
return {
'assignments': valid_assignments,
'total_cost': total_cost,
'assignment_rate': len(valid_assignments) / len(orders) * 100
}
def real_time_reassignment(self, rider_id, reason):
"""
实时重新分配订单
当骑手出现意外情况时调用
"""
# 获取骑手的当前订单
current_orders = self.rider_pool.get_rider_orders(rider_id)
reassignment_results = []
for order in current_orders:
# 如果订单还没有取餐，可以重新分配
if order.status in ['waiting_rider', 'rider_assigned']:
# 取消原有分配
self.cancel_assignment(order.order_id, rider_id, reason)
# 重新分配
result = self.dispatch_order(order)
reassignment_results.append({
'order_id': order.order_id,
'original_rider': rider_id,
'new_rider': result['rider_id'] if result else None,
'success': result is not None
})
return reassignment_results
3.2 实时路径规划与ETA计算
光合同城的路径规划系统不仅考虑最短路径，还综合考虑实时路况、交通规则、天气等因素。
@Service
public class RoutePlanningService {
@Autowired
private MapService mapService;
@Autowired
private TrafficService trafficService;
@Autowired
private WeatherService weatherService;
/**
* 计算最优配送路径
*/
public RoutePlan calculateOptimalRoute(RouteRequest request) {
List<DeliveryPoint> deliveryPoints = request.getDeliveryPoints();
Point startPoint = request.getStartPoint();
// 获取实时路况
TrafficInfo trafficInfo = trafficService.getRealTimeTraffic(
startPoint, deliveryPoints);
// 获取天气信息
WeatherInfo weatherInfo = weatherService.getCurrentWeather(
request.getCityCode());
// 构建路径规划图
RouteGraph graph = buildRouteGraph(deliveryPoints, trafficInfo);
// 使用改进的Dijkstra算法计算最优路径
RoutePlan optimalRoute = findOptimalRoute(graph, startPoint);
// 考虑天气因素调整ETA
adjustETAForWeather(optimalRoute, weatherInfo);
// 考虑骑手习惯和能力调整
adjustForRiderPreference(optimalRoute, request.getRiderId());
return optimalRoute;
}
/**
* 多目标优化路径规划
* 考虑：距离最短、时间最少、成本最低等多个目标
*/
public List<RoutePlan> multiObjectiveRoutePlanning(
RouteRequest request,
OptimizationCriteria criteria) {
// 生成多个候选路径
List<RoutePlan> candidateRoutes = generateCandidateRoutes(request);
// 多目标评分
Map<RoutePlan, MultiObjectiveScore> scores = new HashMap<>();
for (RoutePlan route : candidateRoutes) {
MultiObjectiveScore score = evaluateRoute(route, criteria);
scores.put(route, score);
}
// Pareto最优解筛选
List<RoutePlan> paretoOptimal = findParetoOptimal(scores);
// 根据偏好选择最终路径
return selectFinalRoute(paretoOptimal, request.getPreference());
}
}
四：系统性能优化实践
4.1 数据库查询优化
索引优化策略：
-- 订单表复合索引设计
CREATE INDEX idx_order_user_status ON orders(user_id, status, create_time);
CREATE INDEX idx_order_merchant_time ON orders(merchant_id, create_time);
CREATE INDEX idx_order_rider_status ON orders(rider_id, status);
-- 使用覆盖索引减少回表
CREATE INDEX idx_order_query ON orders(
user_id,
status,
create_time DESC
) INCLUDE (total_amount, merchant_id, rider_id);
4.2 缓存策略实现
@Service
@Slf4j
public class OrderCacheService {
@Autowired
private RedisTemplate<String, Object> redisTemplate;
private static final String ORDER_CACHE_PREFIX = "order:";
private static final String USER_ORDERS_PREFIX = "user_orders:";
private static final long ORDER_CACHE_TTL = 30 * 60; // 30分钟
/**
* 多级缓存获取订单信息
*/
public OrderDTO getOrderWithCache(String orderId) {
// 1. 先查本地缓存（Caffeine）
OrderDTO order = localCache.getIfPresent(orderId);
if (order != null) {
return order;
}
// 2. 查Redis分布式缓存
String cacheKey = ORDER_CACHE_PREFIX + orderId;
order = (OrderDTO) redisTemplate.opsForValue().get(cacheKey);
if (order != null) {
// 回填本地缓存
localCache.put(orderId, order);
return order;
}
// 3. 查数据库
order = orderMapper.selectById(orderId);
if (order != null) {
// 异步更新缓存
CompletableFuture.runAsync(() -> {
updateOrderCache(order);
});
}
return order;
}
/**
* 用户订单列表缓存
*/
public List<OrderDTO> getUserOrdersWithCache(Long userId,
OrderStatus status,
int page,
int size) {
String cacheKey = String.format("%s:%d:%s:%d:%d",
USER_ORDERS_PREFIX, userId, status, page, size);
// 尝试从缓存获取
List<OrderDTO> orders = (List<OrderDTO>)
redisTemplate.opsForValue().get(cacheKey);
if (orders == null) {
// 缓存未命中，查询数据库
orders = orderMapper.selectUserOrders(userId, status, page, size);
// 异步更新缓存（设置较短TTL，因为订单状态可能变化）
CompletableFuture.runAsync(() -> {
redisTemplate.opsForValue().set(
cacheKey,
orders,
5,
TimeUnit.MINUTES
);
});
}
return orders;
}
}
五：安全与监控
5.1 支付安全实现
@Component
public class PaymentSecurityService {
/**
* 支付参数签名验证
*/
public boolean verifyPaymentSignature(PaymentRequest request) {
String sign = request.getSign();
Map<String, String> params = new TreeMap<>();
// 获取所有待签名参数
params.put("order_id", request.getOrderId());
params.put("amount", request.getAmount().toString());
params.put("timestamp", request.getTimestamp());
params.put("nonce_str", request.getNonceStr());
// 生成签名字符串
StringBuilder signStr = new StringBuilder();
for (Map.Entry<String, String> entry : params.entrySet()) {
signStr.append(entry.getKey()).append("=")
.append(entry.getValue()).append("&");
}
signStr.append("key=").append(apiKey);
// 计算签名
String calculatedSign = DigestUtils.md5Hex(signStr.toString())
.toUpperCase();
return calculatedSign.equals(sign);
}
/**
* 防重放攻击
*/
public boolean checkReplayAttack(String timestamp, String nonceStr) {
// 检查时间戳是否在合理范围内
long requestTime = Long.parseLong(timestamp);
long currentTime = System.currentTimeMillis() / 1000;
if (Math.abs(currentTime - requestTime) > 300) { // 5分钟
return false;
}
// 检查nonce是否已使用过
String nonceKey = "payment_nonce:" + nonceStr;
Boolean used = redisTemplate.opsForValue()
.get(nonceKey) != null;
if (used) {
return false;
}
// 记录已使用的nonce，有效期10分钟
redisTemplate.opsForValue()
.set(nonceKey, "1", 10, TimeUnit.MINUTES);
return true;
}
}
结语：
外卖系统的开发不仅是技术实现，更是对业务理解的深度考验。光合同城通过多年的项目实践，总结出一套成熟的外卖平台解决方案。未来，随着5G、物联网、人工智能等技术的发展，外卖系统将更加智能化、个性化。开发者需要持续学习新技术，深入理解业务需求，才能在竞争激烈的市场中脱颖而出。
