Converting a TreeSet to ArrayList?

问题

I have a TreeSet which contains > 100k objects. I have another method which requires ArrayList as an param.

Is there any way I can accomplish this without iterating whole TreeSet and then adding each object manually to ArrayList ?

回答1:

How about this:

new ArrayList<T>(set);

回答2:

ArrayList has a convenience method addAll that fits the bill nicely:

final Set<Object> set = ...
List<Object> list = new ArrayList<Object>(someBigNum);
list.addAll(set);

来源：https://stackoverflow.com/questions/9322405/converting-a-treeset-to-arraylist