java list获取最后一个元素的值,Java获取集合的最后一个元素

I have a collection, I want to get the last element of the collection. What's the most straighforward and fast way to do so?

One solution is to first toArray(), and then return the last element of the array. Is there any other better ones?

解决方案

A Collection is not a necessarily ordered set of elements so there may not be a concept of the "last" element. If you want something that's ordered, you can use a SortedSet which has a last() method. Or you can use a List and call mylist.get(mylist.size()-1);

If you really need the last element you should use a List or a SortedSet. But if all you have is a Collection and you really, really, really need the last element, you could use toArray or you could use an Iterator and iterate to the end of the list. For example:

public Object getLastElement(final Collection c) {

final Iterator itr = c.iterator();

Object lastElement = itr.next();

while(itr.hasNext()) {

lastElement=itr.next();

}

return lastElement;

}