我有以下内容:classA{@XmlElementStringname;//gettersandsetters}和classBextendsA{@XmlElementStringheight;//gettersandsetters}终于有了@XmlRootElementclassP{@XmlElementListthings;//gettersandsetters}如果我这样做Listl=newArrayList();l.add(newB('hello',20))//AddnewBwithheightof20andnamehelloPp=newP();p.setThings(l);//