JAVA 反射机制 抛出原异常

自定义异常类:
public class CustomException extends Exception{
  public CustomException(){}
 
  public CustomException(String message){
    super(message);
  }
 
  // public CustomException(param ..){...}
}

main():

try{
  try{
    Class<?> clazz = Class.forName(className);
    Method method = Clazz.getDeclaredMethod(Param);
    method.invoke();
  }catch(InvocationTargetException ext){
    try{
      throw ext.getTargetException();
    }catch(CustomException cusEx){
      throw cusEx;
    }catch(Throwable e){
      // TODO    
    }
  }
}catch(CustomException ex){
  // TODO
}catch(Exception e){
  // TODO
}