在自己的类中捕获python异常

我现在有个奇怪的问题。 在我的程序中，我试图捕获类内部的异常，de class在一个单独的python文件中使用，但是异常会通过气泡传递到调用文件。 我怎样才能解决这个问题

例如：

main.py

#from sqlalchemy.exc import SQLAlchemyError, DatabaseError
from os import path

from helpers.db import DB
from models.group import Group
from models.entity import Entity
PROJECT_PATH = path.split(path.abspath(__file__))[0]
DATABASE_PATH = PROJECT_PATH + '/datastore/test.db'

class PasswordManager:
    database = DB(DATABASE_PATH)

if __name__ == "__main__":
    PasswordManager()

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.exc import DatabaseError, SQLAlchemyError

from models import *
from helpers import Base
from helpers.crypt import Crypt

class DB:
    SQLEngine = None
    SessionMaker = None
    Session = None
    BuildEngineErrorCount = 0

    def __init__(self, db_path):
        self.buildEngine(db_path)
        self.buildDatabaseModels()

    def buildEngine(self, db_path):
        try:
            self.SQLEngine = create_engine('sqlite:////' + db_path)
            print "trying to build a SQLEngine"
        except BaseException, er:
            print "Errors %s" % er
            for error in er.args:
                if error == '(DatabaseError) file is encrypted or is not a database':
                    self.BuildEngineErrorCount += 1
                    c = Crypt()
                    c.setKey('Test')
                    c.decryptDB(db_path)
                    if self.BuildEngineErrorCount < 5:
                        self.buildEngine(db_path)

    def buildDatabaseModels(self):
        if self.SQLEngine is None:
            raise Exception("No SQLEngine found")
        Base.metadata.create_all(self.SQLEngine, checkfirst=True)

    def createSession(self):
        if self.SessionMaker is not None or self.Session is not None:
            raise Exception("Session already mapped")

        self.SessionMaker = sessionmaker(bind=self.SQLEngine)
        self.Session = self.SessionMaker()
        return self.Session

输出

Traceback (most recent call last):
trying to build a SQLEngine
  File "/home/tom/Projects/test/test/test.py", line 11, in <module>
    class test:
  File "/home/tom/Projects/test/test/test.py", line 23, in test
    database = DB(DATABASE_PATH)
  File "/home/tom/Projects/test/test/helpers/db.py", line 19, in __init__
    self.buildDatabaseModels()
  File "/home/tom/Projects/test/test/helpers/db.py", line 39, in buildDatabaseModels
    Base.metadata.create_all(self.SQLEngine, checkfirst=True)
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/sql/schema.py", line 3308, in create_all
    tables=tables)
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1516, in _run_visitor
    conn._run_visitor(visitorcallable, element, **kwargs)
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1164, in _run_visitor
    **kwargs).traverse_single(element)
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/sql/visitors.py", line 119, in traverse_single
    return meth(obj, **kw)
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/sql/ddl.py", line 696, in visit_metadata
    if self._can_create_table(t)]
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/sql/ddl.py", line 674, in _can_create_table
    table.name, schema=table.schema)
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/dialects/sqlite/base.py", line 781, in has_table
    cursor = _pragma_cursor(connection.execute(statement))
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 709, in execute
    return self._execute_text(object, multiparams, params)
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 858, in _execute_text
    statement, parameters
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 927, in _execute_context
    context)
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 1076, in _handle_dbapi_exception
    exc_info
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/util/compat.py", line 185, in raise_from_cause
    reraise(type(exception), exception, tb=exc_tb)
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py", line 920, in _execute_context
    context)
  File "/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/default.py", line 425, in do_execute
    cursor.execute(statement, parameters)
sqlalchemy.exc.DatabaseError: (DatabaseError) file is encrypted or is not a database u'PRAGMA table_info("groups")' ()

回溯（最近一次呼叫最后一次）：
正在尝试构建SQLEngine
文件“/home/tom/Projects/test/test/test.py”，第11行，在
课堂测试：
文件“/home/tom/Projects/test/test/test.py”，第23行，测试中
database=DB（数据库路径）
文件“/home/tom/Projects/test/test/helpers/db.py”，第19行，在__
self.buildDatabaseModels（）
buildDatabaseModels中的文件“/home/tom/Projects/test/test/helpers/db.py”，第39行
Base.metadata.create_all（self.SQLEngine，checkfirst=True）
文件“/home/tom/Projects/test/local/lib/python2.7/site packages/sqlalchemy/sql/schema.py”，第3308行，在create_all中
表=表）
文件“/home/tom/Projects/test/local/lib/python2.7/site packages/sqlalchemy/engine/base.py”，第1516行，在“运行”中
连接运行访问者（访问者可调用，元素，**kwargs）
文件“/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/engine/base.py”，第1164行，在运行时访问
**kwargs）。单导线（元件）
文件“/home/tom/Projects/test/local/lib/python2.7/site packages/sqlalchemy/sql/visitors.py”，第119行，在traverse_single中
返回方法（obj，**kw）
文件“/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/sql/ddl.py”，第696行，访问元数据
如果是self.\u可以\u创建\u表（t）]
文件“/home/tom/Projects/test/local/lib/python2.7/site packages/sqlalchemy/sql/ddl.py”，第674行，在“cancreate”表中
table.name，schema=table.schema）
文件“/home/tom/Projects/test/local/lib/python2.7/site packages/sqlalchemy/dialogs/sqlite/base.py”，第781行，在has_表中
游标=_pragma_游标（connection.execute（语句））
文件“/home/tom/Projects/test/local/lib/python2.7/site packages/sqlalchemy/engine/base.py”，第709行，在execute中
返回self.\u执行\u文本（对象、多线程、参数）
文件“/home/tom/Projects/test/local/lib/python2.7/site packages/sqlalchemy/engine/base.py”，第858行，文本为
语句、参数
文件“/home/tom/Projects/test/local/lib/python2.7/site packages/sqlalchemy/engine/base.py”，第927行，在执行上下文中
（上下文）
文件“/home/tom/Projects/test/local/lib/python2.7/site packages/sqlalchemy/engine/base.py”，第1076行，在_handle_dbapi_exception中
exc_信息
文件“/home/tom/Projects/test/local/lib/python2.7/site-packages/sqlalchemy/util/compat.py”，第185行，源于
重新释放（类型（异常），异常，tb=exc_tb）
文件“/home/tom/Projects/test/local/lib/python2.7/site packages/sqlalchemy/engine/base.py”，第920行，在执行上下文中
（上下文）
文件“/home/tom/Projects/test/local/lib/python2.7/site packages/sqlalchemy/engine/default.py”，第425行，在do_execute中
cursor.execute（语句、参数）
sqlalchemy.exc.DatabaseError:（DatabaseError）文件已加密或不是数据库u'PRAGMA table_info（“groups”）（）

DB.py

#from sqlalchemy.exc import SQLAlchemyError, DatabaseError
from os import path

from helpers.db import DB
from models.group import Group
from models.entity import Entity
PROJECT_PATH = path.split(path.abspath(__file__))[0]
DATABASE_PATH = PROJECT_PATH + '/datastore/test.db'

class PasswordManager:
    database = DB(DATABASE_PATH)

if __name__ == "__main__":
    PasswordManager()

from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from sqlalchemy.exc import DatabaseError, SQLAlchemyError

from models import *
from helpers import Base
from helpers.crypt import Crypt

class DB:
    SQLEngine = None
    SessionMaker = None
    Session = None
    BuildEngineErrorCount = 0

    def __init__(self, db_path):
        self.buildEngine(db_path)
        self.buildDatabaseModels()

    def buildEngine(self, db_path):
        try:
            self.SQLEngine = create_engine('sqlite:////' + db_path)
            print "trying to build a SQLEngine"
        except BaseException, er:
            print "Errors %s" % er
            for error in er.args:
                if error == '(DatabaseError) file is encrypted or is not a database':
                    self.BuildEngineErrorCount += 1
                    c = Crypt()
                    c.setKey('Test')
                    c.decryptDB(db_path)
                    if self.BuildEngineErrorCount < 5:
                        self.buildEngine(db_path)

    def buildDatabaseModels(self):
        if self.SQLEngine is None:
            raise Exception("No SQLEngine found")
        Base.metadata.create_all(self.SQLEngine, checkfirst=True)

    def createSession(self):
        if self.SessionMaker is not None or self.Session is not None:
            raise Exception("Session already mapped")

        self.SessionMaker = sessionmaker(bind=self.SQLEngine)
        self.Session = self.SessionMaker()
        return self.Session

从sqlalchemy导入创建引擎
从sqlalchemy.orm导入sessionmaker
从sqlalchemy.exc导入数据库错误，SQLAlchemyError
从模型导入*
从助手导入库
从helpers.crypt导入crypt
DB类：
SQLEngine=None
SessionMaker=None
会话=无
BuildEngineErrorCount=0
定义初始化（自我，数据库路径）：
self.buildEngine（db_路径）
self.buildDatabaseModels（）
def构建引擎（自身，数据库路径）：
尝试：
self.SQLEngine=创建引擎（'sqlite:////“+db_路径）
打印“尝试构建SQLEngine”
除此之外呢,呃,
打印“错误%s”%er
对于er.args中的错误：
如果错误=='（DatabaseError）文件已加密或不是数据库'：
self.BuildEngineErrorCount+=1
c=Crypt（）
c、 设置键（“测试”）
c、 解密数据库（数据库路径）
如果self.BuildEngineErrorCount小于5：
self.buildEngine（db_路径）
def buildDatabaseModels（自）：
如果self.SQLEngine为无：
引发异常（“未找到SQLEngine”）
Base.metadata.create_all（self.SQLEngine，checkfirst=True）
def createSession（自）：
如果self.SessionMaker不是None或self.Session不是None：
引发异常（“会话已映射”）
self.SessionMaker=SessionMaker（bind=self.SQLEngine）
self.Session=self.SessionMaker（）
返回self.Session

正如您所看到的，我试图在db类中捕获该异常，但它没有捕获任何内容。

---

有人知道我做错了什么吗？

您的异常来自不同的方法，而不是您尝试的方法。具体来说，例外情况来自

Base.metadata.create_all(self.SQLEngine, checkfirst=True)

---

在

buildDatabaseModels

中，但是除了在

buildEngine

Lol中，您已经尝试过了，您完全正确！我怎么会错过呢！：）Thnx，如果可以，我会将此标记为正确答案（需要等待6分钟）