python加载库

# testInstance.py  
  
import importlib  
import sys  
  
class TestInstance:  
    def __init__(self, projectName):  
        self.projectName = projectName  
        self.lib = self.load_libraries()  
  
    def load_libraries(self):  
        # Import the configuration module  
        import libconfig  
        libraries = {}  
          
        # Append the library paths to sys.path  
        sys.path.append("library/commonlib")  
        sys.path.append("library/projectlib")  
          
        # Load libraries in the specified order  
        for lib_name in libconfig.libraries_order:  
            # Import the library module  
            module = importlib.import_module(lib_name)  
              
            # Add the module's attributes to the libraries dict  
            libraries.update({attr_name: getattr(module, attr_name) for attr_name in dir(module) if not attr_name.startswith('_')})  
          
        # Create a namespace-like object to hold the classes/functions from all libraries  
        class LibraryNamespace:  
            def __getattr__(self, item):  
                # First check if the attribute exists in the current project's libraries  
                if item in libraries:  
                    return libraries[item]  
                # If not found, check commonlib  
                commonlib_module = importlib.import_module(f"commonlib.{item}")  
                return getattr(commonlib_module, item)  
  
        # Return the namespace object  
        return LibraryNamespace()  
  
# Example usage  
if __name__ == '__main__':  
    # Assume the current project name is "projectlib"  
    projectName = "projectlib"  
    test = TestInstance(projectName)  
      
    # Call greet function from libA without explicitly checking for its existence  
    # The framework handles the fallback logic if the function is not found in the project's library  
    print(test.libA.greet("World"))

在这个修改后的代码中，load_libraries方法现在将所有库的属性合并到一个字典中，而LibraryNamespace类则覆盖了__getattr__方法以处理属性的动态查找。当尝试访问test.libA.greet时，如果greet函数在项目的库中不存在，__getattr__方法会尝试从commonlib库中导入libA模块并获取greet函数。

这意味着，脚本中不需要进行任何显式的检查来确定函数的位置。当调用test.libA.greet("World")时，如果函数在项目库中不存在，框架将自动回退到commonlib库并尝试调用该函数。

请确保libconfig.libraries_order列表中的库加载顺序符合你的要求，即项目库应该在commonlib之前，这样项目库中的函数将优先被调用。如果项目库中没有找到函数，那么commonlib中的函数将被调用。