JAVA 从list集合中取出N(多)个不重复的元素

    
    private List createRandoms(List list, int n) {
        Map map = new HashMap();
        List news = new ArrayList();
        if (list.size() <= n) {
            return list;
        } else {
            while (map.size() < n) {
                int random = (int) (Math.random() * list.size());
                if (!map.containsKey(random)) {
                    map.put(random, "");
                    news.add(list.get(random));
                }
            }
            return news;
        }
    }