递归拿到所有子类的id

Listlist2=newArrayList();publicListgetAll(Stringi,Listlist){Iteratoriter=list.iterator();while(iter.hasNext()){Studentstudent=(Student)iter.next();if(i.equals(student.getParentid())){list2.add(student.getId());getAll(student.getId(),list);}}returnlist2;}