在java中实例化泛型类型 [英] Instantiate generic type in java

问题描述

我卡住了。来自C ++，我认为这只会工作，但事实并非如此。你能给我一个建议吗？我会尽量不要在每个用于T的类中创建方法。

  public class A< T> { 
 
 private T t_; 
 
 public A（）{
 t_ = new T（）; //错误
} 
 
} 
  

t想要构造函数看起来像这样：A（Class classT）{...
理想情况下，我想要这样的c ++代码。

 模板< class T> 
 class A {
 private：
 T t_; 
 
 public：
 A（）{} 
 
}; 
  

感谢您的帮助。

解决方案

你不能在Java中做这样的事情。阅读关于删除类型的信息： http://docs.oracle.com/javase/ tutorial / java / generics / erasure.html

I'm stuck. Coming from C++ I thought this would simply work, but it does not. Can you please give me an advice? I will try to not end up with kind of creation method in each class used for T.

public class A<T>{

    private T t_;

    public A(){
        t_ = new T(); //error
    }

}  

Also i don't want to have constructor looking like: A(Class classT){ ... Ideally i would like to have something like this c++ code.

template<class T>
class A{
private:
   T t_;

public:
   A(){}

};

Thanks for help.

解决方案

You cannot do such things in Java. Read about type erasure: http://docs.oracle.com/javase/tutorial/java/generics/erasure.html

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