Cololection 介绍
1. List.contains();
2.List.indexof() ;???? -1
3.List.remove(entity)
4. Arrays.<entity>asList(entity,entity);
5.List.shuffle(list);? 洗牌打乱顺序
6.list.retainAll(list2);? 两个集合的交集
7.list.sublist(); //取得部分集合
8.list.containsAll(list);
9.list.listIterator([args]从第几位开始);??? hasNext()??? next()???? hasPrevious()????? previous()
