关于java：如何在运行时调用接口的子类函数？

how to call subclass function of interface at runtime?

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我有一个由4个不同的类实现的接口。现在，我想通过这个接口的引用调用其中一个类的setter方法。类在运行时确定，接口不包含任何方法或变量。那么，如何设置这些类中某个类的私有变量的值呢？我向您提供代码示例。

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public interface InterfaceClass {
}

public class ClassOne implements InterfaceClass{
private String name;

public void setName(String name) {
this.name = name;
}
}

public class ClassTwo implements InterfaceClass {
private String name;

public void setName(String name) {
this.name = name;
}
}

class CaalingClass {
String className ="ClassOne";// the value of the string is decide at the run time
InterfaceClass i = (InterfaceClass) Class.forName(className).newInstance();
i.setName("ABC"); //this gives an error
/*
* I know it should be ((ClassOne) i).setName("ABC"); but at runtime i
* don know which class is to be called so is there any other way to
* find or it has to be done in this fashion?
*/
}