Map取值技巧

   Map map = new HashMap();  map.put("1", "one");  map.put("2", "two");  map.put("3", "three");    Set keys = map.keySet();  Set keys2 = map.entrySet();  for(Iterator it = keys.iterator(); it.hasNext();) {  String key = (String)it.next();  String value = (String) map.get(key);  System.out.println(key + " " + value);  }  for(Iterator it2 = keys2.iterator();it2.hasNext();) {  Map.Entry e = (Map.Entry)it2.next();  Object k = e.getKey();  Object v = e.getValue();  System.out.println(k + " " + v);  }