Map重复添加一个键的值，只保留最后一次的

如下，只有一个键，值为最后一次添加。

public static void main(String[] args){HashMap<String,String> map = new HashMap<String,String>();map.put("a","ab");map.put("b","ab");map.put("a","ab1");Set<String> keyset = map.keySet();Iterator<String> it = keyset.iterator();while(it.hasNext()){String s = it.next();System.out.println( s+ "......" + map.get(s));}Set<Map.Entry<String,String>> mapEntry = map.entrySet();Iterator<Map.Entry<String,String>> itSet = mapEntry.iterator();while(itSet.hasNext()){Map.Entry<String,String> entry = itSet.next();System.out.println(entry.getKey() + "......" + entry.getValue());}}