如何在java泛型中返回类对象“类型”？
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How to return a class object "type" in java generics?
提问by arzillo
Imagine to have a java class
想象一下有一个java类
public class FixedClassOfStrings {
List<String> myMember=new ArrayList<String>();
// omissed all non relevant code...
public Class getMyType() {
return String.class;
}
}
How can I make it paramteric, by using java generics?
如何通过使用 java 泛型使其参数化？
My attempts fail:
我的尝试失败了：
public class GenericClass<T> {
List<T> myMember=new ArrayList<T>();
public Class getMyType() {
return T.class; // this gives "Illegal class literal for the type parameter T"
}
}
Also, how can I avoid warning: "Class is a raw type. References to generic type Class should be parameterized" in the FixedClassOsStrings? is it ok to declare:
另外，如何避免在 FixedClassOsStrings 中发出警告：“类是原始类型。对泛型类的引用应该参数化”？可以声明：
public Class<String> getMyType() {
return String.class;
}
...
And if it is ok, what shall I return using generics?
如果没问题，我应该使用泛型返回什么？
public Class<T> getMyType() {
return T.class; // this gives "Illegal class literal for the type parameter T"
}
...
All hints will be appreciated!!!
所有提示将不胜感激！！！
回答by Rogue
I would try something like this:
我会尝试这样的事情：
public Class<T> getMyType() {
return /* some instance of T */.getClass();
}
Alternatively, an easy solution is passing the instance upon construction:
或者，一个简单的解决方案是在构造时传递实例：
public class YourClass<T> {
private final Class<T> type;
public YourClass (/* arguments */, Class<T> type) {
this.type = type;
}
public Class<T> getType() {
return this.type;
}
}
