https://blog.youkuaiyun.com/qq_42489613zh-cnhttps://blog.youkuaiyun.com/https://blog.youkuaiyun.com/qq_42489613/article/details/144095354https://blog.youkuaiyun.com/qq_42489613/article/details/144095354qq_42489613Wed, 27 Nov 2024 22:55:41 +0800https://blog.youkuaiyun.com/qq_42489613/article/details/141955276https://blog.youkuaiyun.com/qq_42489613/article/details/141955276qq_42489613Fri, 06 Sep 2024 14:48:39 +0800https://blog.youkuaiyun.com/qq_42489613/article/details/141925426https://blog.youkuaiyun.com/qq_42489613/article/details/141925426qq_42489613Thu, 05 Sep 2024 11:57:38 +0800https://blog.youkuaiyun.com/qq_42489613/article/details/132096614https://blog.youkuaiyun.com/qq_42489613/article/details/132096614qq_42489613Fri, 04 Aug 2023 10:07:57 +0800 表示该列表可以持有 User 类型或 User 的父类型的元素，因此可以向该列表中添加 User 类型或 User 的子类型的对象。extends User> 是一个通配符类型的声明，它表示这个列表可以持有 User 类型或 User 的任何子类型的元素。这样就可以确保列表是具体类型的列表，从而可以添加相应类型的元素。super T> 用于处理添加元素的情况，允许添加 T 类型或 T 的子类型的元素。]]>https://blog.youkuaiyun.com/qq_42489613/article/details/127467812https://blog.youkuaiyun.com/qq_42489613/article/details/127467812qq_42489613Sun, 23 Oct 2022 09:49:14 +0800