判斷Map集合中是否存在某一個key

方法一： Map<String,String> hashmp = ne HashMap(); hashmp.put("aa", "111"); hashmap.containsKey("xxx"); 方法二：keySet() HashMap hashmp = ne HashMap(); hashmp.put("aa", "111"); Set set = hashmp.keySet(); Iterator iter = set.iterator(); while (iter.hasNext()) { String key = (String) iter.next(); // printkey
} // traverse
for (String key : list.get(pos).keySet() ) { myKey = key; } 方法三：entrySet() HashMap map; Iterator i = map.entrySet().iterator(); while (i.hasNext()) { Object obj = i.next(); String key = obj.toString(); } // or
while (i.hasNext()) { Entry entry = (java.util.Map.Entry)it.next(); entry.getkey(); entry.getValue(); }