如何获得泛型类型 T 的类实例?

问题描述

我有一个泛型类，Foo.在Foo的方法中，我想获取T类型的类实例，但是我就是不能调用T.class.

I have a generics class, Foo<T>. In a method of Foo, I want to get the class instance of type T, but I just can't call T.class.

使用 T.class 绕过它的首选方法是什么?

What is the preferred way to get around it using T.class?

推荐答案

简短的回答是，在 Java 中没有办法找出泛型类型参数的运行时类型.我建议阅读 Java 教程中关于类型擦除的章节更多详情.

The short answer is, that there is no way to find out the runtime type of generic type parameters in Java. I suggest reading the chapter about type erasure in the Java Tutorial for more details.

一个流行的解决方案是将类型参数的 Class 传递给泛型类型的构造函数，例如

A popular solution to this is to pass the Class of the type parameter into the constructor of the generic type, e.g.

class Foo<T> {
    final Class<T> typeParameterClass;

    public Foo(Class<T> typeParameterClass) {
        this.typeParameterClass = typeParameterClass;
    }

    public void bar() {
        // you can access the typeParameterClass here and do whatever you like
    }
}

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