python中动态获取子类

当父类和子类都在一个文件下时，直接在父类中调用 __subclassess__就可以获得所有子类，如：

class A(object):
    pass
 
class B(A):
    pass
 
class C(A):
    pass
 
 
for sub in A.__subclasses__():
    print(sub.__name__)

但是当子类和父类不在一个文件下时就会获取不到， 就需要通过动态导包来实现，我这里是父类和子类在同一个目录下，如果目录不同，则自己调整路径就行，代码参考：class A(object):

    @classmethod
    def get_sub(cls):
        """动态获取继承的子类"""        
        rel_path = os.path.relpath(__file__)  # 相对路径，可能项目的根目录会有 .., eg: '..\..\hdyplus\app\services\service_utils\new\api_parse.py'
        package, file_name = os.path.split(rel_path)
        package_list = [str(i) for i in package.split(os.path.sep) if i != '..']
        package = '.'.join(package_list)
        current_path = os.path.dirname(os.path.abspath(__file__))
        current_files = [f.split('.')[0] for f in os.listdir(current_path) if isfile(join(current_path, f))]
        for f in current_files:
            try:
                module = importlib.import_module('.%s' % f, package=package)
                for name, sub in inspect.getmembers(module):
                    if inspect.isclass(sub):  # 类别是class，并且父类是A
                        if sub_class.__base__ == cls:
                            print(sub.__name__)
            except Exception as e:
                pass