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我无法理解为什么我会收到此错误,说明如果有人可以帮助我解决连接类型的连接未初始化。
在此处输入图像描述
在您的主要方法中,您正在编写
Connection connection; // connection is still null UserService sut = UserService(r, connection);
但是正如您的错误消息所说:您不能使用为空UserService的connection变量进行实例化。您必须重新编写代码,以便在初始化 UserService 时变量不会为空
UserService
connection