施用iterator

使用iterator
最近看书，看到iterator用法。


写个简单的printAll

 public static void printAll (Iterator iter) {        while (iter.hasNext())            System.out.println(iter.next().toString());    }public static void main (String[] args) {        HashMap this_map = new HashMap();        Random ran = new Random();        for (int i = 1; i  list = new ArrayList();        for (int i = 1; i < 10; i++) {            list.add(ran.nextInt());        }        printAll(this_map.keySet().iterator());        printAll(list.iterator());    }}