我想实现一个返回JAXBElement的方法，下面是代码@XmlRootElement(name="history")@XmlAccessorType(XmlAccessType.FIELD)publicclassIBHistoryInfo{@XmlElement(name="trade")privateListmTrade;publicvoidupdateTradeValue(intreqId,Stringdate,doubleopen,doublehigh,doublelow,doubleclose,intvolume,intcount,doubleWAP,booleanhasGa