import java.util.*;

public class HashMapDemo {

​

   public static void main(String args[]) {

      HashMap hm = new HashMap();

​

      hm.put("Zara", new Double(3434.34));

      hm.put("Mahnaz", new Double(123.22));

      hm.put("Ayan", new Double(1378.00));

      hm.put("Daisy", new Double(99.22));

      hm.put("Qadir", new Double(-19.08));

      // 获取一系列数据集合

      Set set = hm.entrySet();

      // 获取一个迭代器

      Iterator i = set.iterator();

      while(i.hasNext()) {

         Map.Entry me = (Map.Entry)i.next();

         System.out.print(me.getKey() + ": ");

         System.out.println(me.getValue());

      }

      System.out.println();

      double balance = ((Double)hm.get("Zara")).doubleValue();

      hm.put("Zara", new Double(balance + 1000));

      System.out.println("Zara's new balance: " + hm.get("Zara"));

   }

}