京东电商下单黄金链路：防止订单重复提交与支付的深度解析

java复制代码
import java.util.HashMap;  
import java.util.Map;  
import java.util.concurrent.locks.Lock;  
import java.util.concurrent.locks.ReentrantLock;  
import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.stereotype.Service;  
import org.springframework.web.bind.annotation.PostMapping;  
import org.springframework.web.bind.annotation.RequestBody;  
import org.springframework.web.bind.annotation.RestController;  
import org.springframework.http.ResponseEntity;  
@Service
public class OrderService {  
private Map<String, String> orderStatusMap = new HashMap<>();  
private Lock lock = new ReentrantLock();  
public String generateOrderNumber(Order order) {  
String uniqueInfo = order.getProduct() + order.getPrice() + order.getUser();  
String orderNumber = MD5Util.md5(uniqueInfo);  
        order.setOrderNumber(orderNumber);  
        saveOrderToDatabase(order);  
return orderNumber;  
    }  
public boolean isOrderPaid(String orderNumber) {  
return orderStatusMap.containsKey(orderNumber) && "PAID".equals(orderStatusMap.get(orderNumber));  
    }  
public void updateOrderStatus(String orderNumber, String status) {  
        lock.lock();  
try {  
            orderStatusMap.put(orderNumber, status);  
        } finally {  
            lock.unlock();  
        }  
    }  
private void saveOrderToDatabase(Order order) {  
// Save order to database logic  
    }  
}  
@RestController
public class PaymentController {  
@Autowired
private OrderService orderService;  
@PostMapping("/payment")
public ResponseEntity<?> makePayment(@RequestBody PaymentRequest request) {  
String orderNumber = request.getOrderNumber();  
if (orderService.isOrderPaid(orderNumber)) {  
return ResponseEntity.badRequest("Payment has been processed");  
        }  
// Perform payment logic  
boolean paymentSuccess = performPayment(request);  
if (paymentSuccess) {  
            orderService.updateOrderStatus(orderNumber, "PAID");  
return ResponseEntity.ok("Payment successful");  
        } else {  
return ResponseEntity.badRequest("Payment failed");  
        }  
    }  
private boolean performPayment(PaymentRequest request) {  
// Payment logic  
return true; // For demonstration purposes, always return true  
    }  
}  
class Order {  
private String product;  
private double price;  
private String user;  
private String orderNumber;  
// Getters and setters  
}  
class PaymentRequest {  
private String orderNumber;  
// Getters and setters  
}  
class MD5Util {  
public static String md5(String input) {  
// MD5 hashing logic  
return "hashed_value";  
    }  
}