什么是Java中的泛型数组的最简单的方法吗？ [英] What is the easiest alternative to a generic array in Java?

问题描述

假设我有这样的：

class test<T>
{
    private T[] elements;
    private int size;
    public test(int size)
    {
        this.size = size;
        elements = new T[this.size];
    }
}

看来这是不可能的，因为编译器不知道一旦它试图取代仿制药code或东西叫什么构造函数。我想知道的是，我怎么会去这样做？我想这是可能的，给了它在C ++中如何轻松完成。

It seems this isn't possible because the compiler doesn't know what constructor to call once it tries to replace the generics code or something. What I'm wondering is, how would I go about doing this? I imagine it is possible, given how easily done it is in C++.

编辑：对不起，我忘了[]中的元素声明

Sorry I forgot the [] in the elements declaration.

推荐答案

现在的问题是，既然泛型类型参数 T 转化为对象由编译器（这就是所谓的类型擦除的）时，实际上创建对象的数组。你可以做的是提供一个类＆LT; T＆GT; 的功能：

The problem is that since the generic type parameter T is transformed into Object by the compiler (it's called type erasure), you actually create an array of Object. What you can do is provide a Class<T> to the function:

class test<T>
{
    private T[] elements;
    private int size;
    public test(Class<T> type, int size)
    {
        this.size = size;
        elements = (T[]) Array. newInstance(type, size);
    }
}

您会发现在这里更好的exlanation：<一href=\"http://www.angelikalanger.com/GenericsFAQ/FAQSections/TypeParameters.html#Can%20I%20create%20an%20array%20whose%20component%20type%20is%20a%20type%20parameter?\"相对=nofollow>安格莉卡兰格 - 我可以创建一个数组，其组件类型为类型参数

You will find a better exlanation of it here: Angelika Langer - Can I create an array whose component type is a type parameter?

这篇关于什么是Java中的泛型数组的最简单的方法吗？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！