// 錯(cuò)誤做法 - 異常被完全忽略
try {
    processOrder();
} catch (Exception e) {
    // 空catch塊 - 極其危險(xiǎn)!
}

// 正確做法 - 至少記錄日志
try {
    processOrder();
} catch (Exception e) {
    logger.error("訂單處理失敗", e);
}

// 錯(cuò)誤做法 - 過(guò)于泛化的異常
throw new Exception("操作失敗");

// 正確做法 - 提供具體信息
throw new OrderProcessingException("訂單ID: " + orderId + " 庫(kù)存不足，當(dāng)前庫(kù)存: " + currentStock);

// 受檢異常 (Checked Exception) - 必須處理
try {
    FileInputStream file = new FileInputStream("file.txt");
} catch (FileNotFoundException e) {
    // 必須捕獲或聲明拋出
}

// 非受檢異常 (Unchecked Exception) - 可不處理
// RuntimeException及其子類(lèi)，如NullPointerException, IllegalArgumentException等

// 業(yè)務(wù)異常類(lèi)
public class BusinessException extends RuntimeException {
    private String errorCode;
    
    public BusinessException(String errorCode, String message) {
        super(message);
        this.errorCode = errorCode;
    }
    
    public String getErrorCode() {
        return errorCode;
    }
}

// 使用自定義異常
public void transferMoney(Account from, Account to, BigDecimal amount) {
    if (from.getBalance().compareTo(amount) < 0) {
        throw new BusinessException("INSUFFICIENT_BALANCE", 
            "賬戶余額不足，當(dāng)前余額: " + from.getBalance());
    }
    // 轉(zhuǎn)賬邏輯...
}

@ControllerAdvice
public class GlobalExceptionHandler {
    
    private static final Logger logger = LoggerFactory.getLogger(GlobalExceptionHandler.class);
    
    // 處理業(yè)務(wù)異常
    @ExceptionHandler(BusinessException.class)
    @ResponseBody
    public ResponseEntity<ErrorResponse> handleBusinessException(BusinessException ex) {
        logger.warn("業(yè)務(wù)異常: {}", ex.getMessage());
        ErrorResponse error = new ErrorResponse(ex.getErrorCode(), ex.getMessage());
        return new ResponseEntity<>(error, HttpStatus.BAD_REQUEST);
    }
    
    // 處理系統(tǒng)異常
    @ExceptionHandler(Exception.class)
    @ResponseBody
    public ResponseEntity<ErrorResponse> handleSystemException(Exception ex) {
        logger.error("系統(tǒng)異常", ex);
        ErrorResponse error = new ErrorResponse("SYSTEM_ERROR", "系統(tǒng)繁忙，請(qǐng)稍后重試");
        return new ResponseEntity<>(error, HttpStatus.INTERNAL_SERVER_ERROR);
    }
    
    // 處理數(shù)據(jù)校驗(yàn)異常
    @ExceptionHandler(MethodArgumentNotValidException.class)
    @ResponseBody
    public ResponseEntity<ErrorResponse> handleValidationException(MethodArgumentNotValidException ex) {
        String errorMessage = ex.getBindingResult().getFieldErrors().stream()
            .map(FieldError::getDefaultMessage)
            .collect(Collectors.joining(", "));
        
        ErrorResponse error = new ErrorResponse("VALIDATION_ERROR", errorMessage);
        return new ResponseEntity<>(error, HttpStatus.BAD_REQUEST);
    }
}

// 統(tǒng)一的錯(cuò)誤響應(yīng)體
@Data
@AllArgsConstructor
class ErrorResponse {
    private String code;
    private String message;
    private long timestamp = System.currentTimeMillis();
}

// 統(tǒng)一格式的API響應(yīng)
@Data
public class ApiResponse<T> {
    private boolean success;
    private T data;
    private ErrorInfo error;
    
    public static <T> ApiResponse<T> success(T data) {
        ApiResponse<T> response = new ApiResponse<>();
        response.setSuccess(true);
        response.setData(data);
        return response;
    }
    
    public static ApiResponse<?> failure(String code, String message) {
        ApiResponse<?> response = new ApiResponse<>();
        response.setSuccess(false);
        response.setError(new ErrorInfo(code, message));
        return response;
    }
}

@Data
@AllArgsConstructor
class ErrorInfo {
    private String code;
    private String message;
}

@Service
@Transactional
public class OrderService {
    
    // 默認(rèn)情況下，只有RuntimeException會(huì)回滾事務(wù)
    public void createOrder(Order order) {
        try {
            orderRepository.save(order);
            inventoryService.reduceStock(order.getProductId(), order.getQuantity());
            // 其他業(yè)務(wù)邏輯...
        } catch (InventoryException e) {
            // 庫(kù)存不足，需要回滾事務(wù)
            throw new RuntimeException("庫(kù)存操作失敗", e); // 這會(huì)觸發(fā)回滾
        }
    }
    
    // 指定特定異常也回滾事務(wù)
    @Transactional(rollbackFor = BusinessException.class)
    public void processRefund(String orderId) throws BusinessException {
        // 退款邏輯...
    }
}

// Service層示例
@Service
public class UserService {
    
    @Autowired
    private UserRepository userRepository;
    
    public User getUserById(Long id) {
        try {
            return userRepository.findById(id)
                .orElseThrow(() -> new BusinessException("USER_NOT_FOUND", "用戶不存在"));
        } catch (DataAccessException e) {
            throw new SystemException("數(shù)據(jù)庫(kù)訪問(wèn)異常", e);
        }
    }
    
    public void createUser(User user) {
        if (userRepository.existsByUsername(user.getUsername())) {
            throw new BusinessException("USERNAME_EXISTS", "用戶名已存在");
        }
        
        try {
            userRepository.save(user);
        } catch (DataAccessException e) {
            throw new SystemException("用戶創(chuàng)建失敗", e);
        }
    }
}

try {
    processPayment(order);
} catch (PaymentException e) {
    // 記錄必要的上下文信息
    logger.error("支付處理失敗, 訂單ID: {}, 用戶ID: {}, 錯(cuò)誤: {}", 
        order.getId(), order.getUserId(), e.getMessage(), e);
    throw new BusinessException("PAYMENT_FAILED", "支付失敗，請(qǐng)重試或聯(lián)系客服");
}

// 定義錯(cuò)誤碼枚舉
public enum ErrorCode {
    // 用戶相關(guān)
    USER_NOT_FOUND("1001", "用戶不存在"),
    USERNAME_EXISTS("1002", "用戶名已存在"),
    
    // 訂單相關(guān)
    ORDER_NOT_FOUND("2001", "訂單不存在"),
    INSUFFICIENT_STOCK("2002", "庫(kù)存不足"),
    
    // 系統(tǒng)相關(guān)
    SYSTEM_ERROR("5000", "系統(tǒng)繁忙，請(qǐng)稍后重試");
    
    private final String code;
    private final String message;
    
    // 構(gòu)造方法、getter...
}

// 前端API調(diào)用示例
api.createOrder(orderData)
  .then(response => {
    // 處理成功響應(yīng)
  })
  .catch(error => {
    if (error.response.data.code === 'INSUFFICIENT_STOCK') {
      // 顯示庫(kù)存不足的特定UI
      showStockWarning();
    } else if (error.response.data.code === 'SYSTEM_ERROR') {
      // 顯示系統(tǒng)錯(cuò)誤提示
      showSystemError();
    } else {
      // 顯示通用錯(cuò)誤提示
      showError(error.response.data.message);
    }
  });