实例化Java中的通用对象 [英] Instantiating generic objects in Java

问题描述

是否可以像下面的代码片段中那样在Java中实例化通用对象?我知道在C#中是可能的.但是，我还没有在Java中看到类似的机制.

Is it possible to instantiate generic objects in Java as does in the following code fragment? I know that it is possible in C#. But, I haven not seen a similar mechanism yet in Java.

// Let T be a generic type.
T t = new T();

推荐答案

不，由于类型擦除，在Java中不起作用.在执行代码时，代码不知道T是什么.

No, that doesn't work in Java, due to type erasure. By the time that code is executing, the code doesn't know what T is.

请参阅 Java泛型FAQ 有关Java泛型的更多信息: )-特别是，请参见类型擦除部分.

See the Java Generics FAQ more more information about Java generics than you ever wanted :) - in particular, see the Type Erasure section.

如果出于这种原因或其他原因需要在执行时知道T的类型，可以将其存储在Class<T>中，并将其放入构造函数中:

If you need to know the type of T at execution time, for this or other reasons, you can store it in a Class<T> and take it in the constructor:

private Class<T> realTypeOfT;

public Foo(Class<T> clazz) {
  realTypeOfT = clazz;
}

然后您可以呼叫newInstance()等.

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