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'''
全局只允许一个实例的办法,
在该电商系统中,全局只有一个数据库连接,使用单例模式确保在整个应用程序内只创建一次数据库连接实例。
'''
class DatabaseConnection:
_instance = None
def __new__(cls):
if not cls._instance:
cls._instance = super().__new__(cls)
cls._instance.connect_to_db()
return cls._instance
def connect_to_db(self):
# 连接到数据库的代码...
pass