Python中异常链(Exception Chaining)的使用

try:
    # 可能引发异常的代码
    1 / 0
except ZeroDivisionError:
    # 在处理过程中又引发了新异常（主动抛出新异常）
    raise ValueError("处理除零错误时出错")

Traceback (most recent call last):
  File "D:\PythonProject\Learn_250816\except_chain.py", line 3, in <module>
    1 / 0
    ~~^~~
ZeroDivisionError: division by zero

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "D:\PythonProject\Learn_250816\except_chain.py", line 6, in <module>
    raise ValueError("处理除零错误时出错")
ValueError: 处理除零错误时出错

try:
    1 / 0
except ZeroDivisionError as original_error:
    raise ValueError("新错误") from original_error

Traceback (most recent call last):
  File "D:\PythonProject\Learn_250816\except_chain.py", line 10, in <module>
    1 / 0
    ~~^~~
ZeroDivisionError: division by zero

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "D:\PythonProject\Learn_250816\except_chain.py", line 12, in <module>
    raise ValueError("新错误") from original_error
ValueError: 新错误

try:
    1 / 0
except ZeroDivisionError:
    raise ValueError("新错误") from None

Traceback (most recent call last):
  File "D:\PythonProject\Learn_250816\except_chain.py", line 17, in <module>
    raise ValueError("新错误") from None
ValueError: 新错误

try:
    try:
        1 / 0
    except ZeroDivisionError as e:
        raise ValueError("新错误") from e
except ValueError as ve:
    print(f"当前异常: {ve}")
    print(f"显式原因: {ve.__cause__}")
    print(f"隐式上下文: {ve.__context__}")

当前异常: 新错误
显式原因: division by zero
隐式上下文: division by zero

try:
    try:
        1 / 0
    except ZeroDivisionError as e:
        raise ValueError("新错误")
except ValueError as ve:
    print(f"当前异常: {ve}")
    print(f"显式原因: {ve.__cause__}")
    print(f"隐式上下文: {ve.__context__}")

当前异常: 新错误
显式原因: None
隐式上下文: division by zero

try:
    config = load_config()
except FileNotFoundError as e:
    raise ConfigurationError("配置文件缺失") from e

try:
    process_data(data)
except ProcessingError as e:
    raise ProcessingError(f"处理ID为{data.id}的记录时出错") from e

try:
    connect_to_database()
except DatabaseError:
    raise ServiceUnavailableError("服务暂时不可用") from None