Day 4 Java业务逻辑层开发（Service）

public interface OrderService { /** * 创建新订单 * @param orderDto 订单DTO对象 * @return 创建成功的订单 * @throws BusinessException 业务异常 */ OrderVO createOrder(OrderDTO orderDto) throws BusinessException; /** * 取消订单 * @param orderId 订单ID * @throws OrderNotFoundException 订单不存在异常 */ void cancelOrder(Long orderId) throws OrderNotFoundException; // 其他业务方法... }

import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; @Service public class OrderServiceImpl implements OrderService { private final OrderRepository orderRepository; private final InventoryService inventoryService; private final PaymentService paymentService; // 使用构造器注入依赖 public OrderServiceImpl(OrderRepository orderRepository, InventoryService inventoryService, PaymentService paymentService) { this.orderRepository = orderRepository; this.inventoryService = inventoryService; this.paymentService = paymentService; } @Override @Transactional(rollbackFor = BusinessException.class) public OrderVO createOrder(OrderDTO orderDto) throws BusinessException { // 1. 验证库存 if (!inventoryService.checkInventory(orderDto.getProductId(), orderDto.getQuantity())) { throw new BusinessException("库存不足"); } // 2. 创建订单实体 Order order = new Order(); // 设置订单属性... // 3. 扣减库存 inventoryService.deductInventory(orderDto.getProductId(), orderDto.getQuantity()); // 4. 处理支付 PaymentResult paymentResult = paymentService.processPayment(orderDto.getPaymentInfo()); if (!paymentResult.isSuccess()) { // 支付失败，回滚事务 throw new BusinessException("支付失败：" + paymentResult.getMessage()); } // 5. 保存订单 Order savedOrder = orderRepository.save(order); // 6. 返回订单VO return convertToVO(savedOrder); } // 其他方法实现... }

@Service public class OrderServiceImpl implements OrderService { @Transactional(propagation = Propagation.REQUIRED, isolation = Isolation.DEFAULT, timeout = 30, rollbackFor = {BusinessException.class, SQLException.class}) public OrderVO createOrder(OrderDTO orderDto) { // 业务逻辑... } @Transactional(propagation = Propagation.REQUIRES_NEW) public void updateInventory(Long productId, int quantity) { // 更新库存... } }

public class BusinessException extends RuntimeException { private final String errorCode; private final String errorMessage; public BusinessException(String errorCode, String errorMessage) { super(errorMessage); this.errorCode = errorCode; this.errorMessage = errorMessage; } // Getters... } public class OrderNotFoundException extends BusinessException { public OrderNotFoundException(Long orderId) { super("ORDER_NOT_FOUND", "订单不存在，ID: " + orderId); } }

@RestControllerAdvice public class GlobalExceptionHandler { @ExceptionHandler(BusinessException.class) public ResponseEntity<ErrorResponse> handleBusinessException(BusinessException ex) { ErrorResponse errorResponse = new ErrorResponse( ex.getErrorCode(), ex.getErrorMessage(), LocalDateTime.now() ); return new ResponseEntity<>(errorResponse, HttpStatus.BAD_REQUEST); } @ExceptionHandler(Exception.class) public ResponseEntity<ErrorResponse> handleGlobalException(Exception ex) { ErrorResponse errorResponse = new ErrorResponse( "SYSTEM_ERROR", "系统内部错误，请联系管理员", LocalDateTime.now() ); return new ResponseEntity<>(errorResponse, HttpStatus.INTERNAL_SERVER_ERROR); } }

import org.junit.jupiter.api.Test; import org.junit.jupiter.api.extension.ExtendWith; import org.mockito.InjectMocks; import org.mockito.Mock; import org.mockito.junit.jupiter.MockitoExtension; @ExtendWith(MockitoExtension.class) class OrderServiceTest { @Mock private OrderRepository orderRepository; @Mock private InventoryService inventoryService; @Mock private PaymentService paymentService; @InjectMocks private OrderServiceImpl orderService; @Test void createOrder_Success() { // 1. 准备测试数据 OrderDTO orderDto = new OrderDTO(1L, 2, "CREDIT_CARD"); Order expectedOrder = new Order(1L, 2, "PENDING"); // 2. 模拟依赖行为 Mockito.when(inventoryService.checkInventory(1L, 2)).thenReturn(true); Mockito.when(paymentService.processPayment(any())).thenReturn(new PaymentResult(true, "Success")); Mockito.when(orderRepository.save(any())).thenReturn(expectedOrder); // 3. 执行测试方法 OrderVO result = orderService.createOrder(orderDto); // 4. 验证结果 Assertions.assertNotNull(result); Assertions.assertEquals(1L, result.getId()); Assertions.assertEquals("PENDING", result.getStatus()); // 5. 验证依赖调用 Mockito.verify(inventoryService).deductInventory(1L, 2); Mockito.verify(orderRepository).save(any()); } @Test void createOrder_InventoryCheckFailed() { // 准备测试数据 OrderDTO orderDto = new OrderDTO(1L, 10, "CREDIT_CARD"); // 模拟库存检查失败 Mockito.when(inventoryService.checkInventory(1L, 10)).thenReturn(false); // 验证抛出业务异常 BusinessException exception = Assertions.assertThrows(BusinessException.class, () -> orderService.createOrder(orderDto)); // 验证异常消息 Assertions.assertEquals("库存不足", exception.getErrorMessage()); } }