如何确定泛型类型的类? [英] How to determine the class of a generic type?

问题描述

我正在创建一个泛型类，并且在其中一种方法中我需要知道当前使用的泛型类型的类.原因是我调用的方法之一期望将其作为参数.

I'm creating a generic class and in one of the methods I need to know the Class of the generic type currently in use. The reason is that one of the method's I call expects this as an argument.

示例:

public class MyGenericClass<T> {
  public void doSomething() {
    // Snip...
    // Call to a 3rd party lib
    T bean = (T)someObject.create(T.class);
    // Snip...
  }
}

显然上面的例子不起作用并导致以下错误:类型参数 T 的类文字非法.

Clearly the example above doesn't work and results in the following error: Illegal class literal for the type parameter T.

我的问题是:有人知道一个好的替代方案或解决方法吗?

My question is: does someone know a good alternative or workaround for this?

推荐答案

还是一样的问题: 通用信息在运行时被擦除，无法恢复.一种解决方法是在静态方法的参数中传递类 T:

Still the same problems : Generic informations are erased at runtime, it cannot be recovered. A workaround is to pass the class T in parameter of a static method :

public class MyGenericClass<T> {

    private final Class<T> clazz;

    public static <U> MyGenericClass<U> createMyGeneric(Class<U> clazz) {
        return new MyGenericClass<U>(clazz);
    }

    protected MyGenericClass(Class<T> clazz) {
        this.clazz = clazz;
    }

    public void doSomething() {
        T instance = clazz.newInstance();
    }
}

它很丑，但很管用.

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