java - 如何在java中的其他方法上将通用对象作为通用参数传递？
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How to pass generic Object as a Generic parameter on other method in java?
提问by lethanh
I meet a trouble in using generic method
我在使用泛型方法时遇到了麻烦
Compiled class:
编译类：
public class Something<T> {
public static Something newInstance(Class<T> type){};
public <T> void doSomething(T input){};
}
and my method is:
我的方法是：
public <S> void doOtherThing(S input){
Something smt = Something.newInstance(input.getClass());
smt.doSomething(input); // Error here
}
It got error at Compile time:
编译时报错：
no suitable method found for doSomething(T) T cannot be converted to capture#1 of ? extends java.lang.Object ...
没有找到适合 doSomething(T) 的方法 T 不能转换为 ? 扩展 java.lang.Object ...
I think there might be a trick to avoid this, please help
我认为可能有一个技巧可以避免这种情况，请帮忙
采纳答案by ChenHuang
I think input.getClass()need be cast to Class<T>
我认为input.getClass()需要强制转换为Class<T>
public <S> void doOtherThing(S input){
Something smt = Something.newInstance((Class<T>)input.getClass());
smt.doSomething(input);
}
回答by Ivan
Anything like this? (generic type declaration thingy on our newInstance method)
有这样的吗？（我们的 newInstance 方法上的通用类型声明）
public class Something<T> {
public static <T> Something<T> newInstance(Class<T> type){ return null; }
public <T> void doSomething(T input){};
}
回答by Bastien
Pass the S class as an argument.
将 S 类作为参数传递。
public class Something<T>
{
public static <T> Something<T> newInstance(Class<T> type)
{
return new Something<T>();
}
public void doSomething(T input){;}
public <S> void doOtherThing(Class<S> clazz, S input)
{
Something<S> smt = Something.newInstance(clazz);
smt.doSomething(input);
}
}
