题解 | 类型判断

import java.util.Scanner;
public class Main
{
    public static void main(String[] args) throws Exception
     {
        Scanner scanner = new Scanner(System.in);
        while (scanner.hasNext()) {
            String className = scanner.next();
            Base obj = (Base) Class.forName(className).newInstance();
            System.out.println(getClassName(obj));
        }
    }
    public static String getClassName(Base obj) 
    {
        return obj.pr();
    }

}

class Base {
  public String pr()
  {
    return "Base";
  }
}

class Sub1 extends Base {
     public String pr()
  {
    return "Sub1";
  }
}

class Sub2 extends Base {
    public String pr()
  {
    return "Sub2";
  }
}