raise [異常類型] [異常信息]

raise

raise ExceptionType

raise ExceptionType("錯誤信息")

raise ExceptionType("錯誤信息") from 原始異常

def divide(a, b):
    if b == 0:
        raise ValueError("除數不能為零")
    return a / b

def process_data(data):
    if not data:
        raise ValueError("數據不能為空")
    if len(data) < 10:
        raise ValueError("數據長度不足")

def withdraw_money(account, amount):
    if amount <= 0:
        raise ValueError("取款金額必須大于零")
    if amount > account.balance:
        raise InsufficientFundsError("余額不足")

try:
    # 可能出錯的代碼
    result = risky_operation()
except Exception as e:
    # 記錄日志
    logger.error(f"操作失敗: {e}")
    # 重新拋出異常
    raise

class CustomError(Exception):
    """自定義異常基類"""
    pass

class ValidationError(CustomError):
    """驗證錯誤"""
    pass

class BusinessError(CustomError):
    """業(yè)務邏輯錯誤"""
    pass

class DatabaseError(Exception):
    def __init__(self, message, error_code=None, table=None):
        super().__init__(message)
        self.error_code = error_code
        self.table = table

# 使用示例
raise DatabaseError("連接失敗", error_code="DB001", table="users")

try:
    # 嘗試讀取文件
    with open("nonexistent.txt") as f:
        data = f.read()
except FileNotFoundError as e:
    # 重新拋出異常，保留原始信息
    raise RuntimeError("無法處理文件") from e

# 不好的做法
raise ValueError("錯誤")

# 好的做法
raise ValueError("年齡必須是正整數，當前值: 25.5")

def validate_user(user):
    errors = []
    
    if not user.name:
        errors.append("用戶名不能為空")
    if user.age < 0:
        errors.append("年齡不能為負數")
    if user.email and '@' not in user.email:
        errors.append("郵箱格式不正確")
    
    if errors:
        raise ValidationError(f"用戶驗證失敗: {'; '.join(errors)}")

try:
    result = external_api_call()
except requests.RequestException as e:
    raise BusinessError("外部服務調用失敗") from e

def safe_operation():
    try:
        # 可能出錯的代碼
        result = risky_function()
        return result
    except SpecificError as e:
        # 處理特定異常
        logger.warning(f"特定錯誤: {e}")
        # 重新拋出
        raise
    except Exception as e:
        # 處理其他異常
        logger.error(f"未知錯誤: {e}")
        # 轉換為自定義異常
        raise BusinessError("操作失敗") from e

def level3():
    raise ValueError("這是第三層的錯誤")

def level2():
    try:
        level3()
    except ValueError as e:
        raise RuntimeError("第二層捕獲并重新拋出") from e

def level1():
    try:
        level2()
    except RuntimeError as e:
        print(f"第一層捕獲: {e}")
        print(f"原始錯誤: {e.__cause__}")

class ErrorReporter:
    def report_error(self, error, context=None):
        error_info = {
            "type": type(error).__name__,
            "message": str(error),
            "context": context,
            "timestamp": datetime.now().isoformat()
        }
        # 上報錯誤信息
        self.send_to_monitoring_system(error_info)

def monitored_function():
    try:
        # 業(yè)務邏輯
        result = business_logic()
        return result
    except Exception as e:
        # 上報錯誤
        error_reporter.report_error(e, {"function": "monitored_function"})
        # 重新拋出異常
        raise

class ErrorLevel:
    CRITICAL = 1
    HIGH = 2
    MEDIUM = 3
    LOW = 4

def handle_error_with_level(error, level):
    if level == ErrorLevel.CRITICAL:
        # 立即上報并停止服務
        report_critical_error(error)
        raise SystemExit(1)
    elif level == ErrorLevel.HIGH:
        # 上報并記錄
        report_high_priority_error(error)
        raise
    else:
        # 僅記錄
        log_error(error)
        raise

# 不好的做法：過度使用異常
def get_user_age(user):
    if not user:
        raise ValueError("用戶對象不能為空")
    if not hasattr(user, 'age'):
        raise AttributeError("用戶對象沒有age屬性")
    if user.age is None:
        raise ValueError("用戶年齡不能為空")
    return user.age

# 好的做法：合理使用異常
def get_user_age(user):
    if not user or not hasattr(user, 'age') or user.age is None:
        raise ValueError("無法獲取用戶年齡")
    return user.age

# 不好的做法
try:
    # 業(yè)務邏輯
    pass
finally:
    # 清理資源
    cleanup()
    raise RuntimeError("清理失敗")  # 這會覆蓋原始異常

# 正確的做法
try:
    # 業(yè)務邏輯
    pass
except Exception as e:
    # 記錄原始異常
    logger.error("原始錯誤", exc_info=True)
    # 拋出新的異常
    raise CustomError("處理失敗") from e

import traceback

try:
    # 可能出錯的代碼
    pass
except Exception as e:
    # 打印完整的堆棧跟蹤
    print("異常信息:", str(e))
    print("堆棧跟蹤:")
    traceback.print_exc()
    raise

def format_exception_info(error):
    return {
        "type": type(error).__name__,
        "message": str(error),
        "traceback": traceback.format_exc(),
        "args": error.args
    }