java 如何将元素添加到泛型集合
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How to add element to a generic collection
提问by user496949
I am wondering how to add a specialized object to a generic collection
我想知道如何将专门的对象添加到通用集合中
I am using the following code
我正在使用以下代码
Collection<T> c;
Class1 object1 = new Class1()
c.add((T)object1)
Is this the correct way?
这是正确的方法吗?
回答by Greg
If your collection is intended to hold only instances of Class1, you should do:
如果您的集合仅用于保存 Class1 的实例,您应该执行以下操作:
Collection<Class1> c;
Class1 object1 = new Class1();
c.add(object1);
回答by anubhava
Or you have the option of keeping your collection really open using wildcard
generics (though I didn't understand your intent behind this requirement) using code like this:
或者您可以选择使用wildcard
泛型(虽然我不明白您在此要求背后的意图)使用如下代码保持您的集合真正开放:
Collection<?> c;
Class1 object1 = new Class1()
c.add(object1)
It won't require any casting either.
它也不需要任何铸造。