问答题 import java.util.*; public class Hashtable1{ public static void main(String args[]){ Hashtable balance=new Hashtable(); Enumeration names; String str; double bal; balance.put("王东",new Double(3434.34)); balance.put("李图闵",new Double(123.22)); balance.put("甲书生",new Double(1378.00)); //显示hash表中所有余额 names=balance.keys(); while(names.hasMoreElements()){ str=(String)names.nextElement(); System.out.println(str+":"+balance.get(str)); } //在李图闵账户存入1,000元 bal=((Double)balance.get("李图闵")).______; balance.put("李图闵",new Double(bal+1000)); System.out.println("李图闵的新余额:"+balance.get("李图闵")); } }